Chris Lattner | 233f7dc | 2002-08-12 21:17:25 +0000 | [diff] [blame] | 1 | //===- InstructionCombining.cpp - Combine multiple instructions -----------===// |
John Criswell | b576c94 | 2003-10-20 19:43:21 +0000 | [diff] [blame] | 2 | // |
| 3 | // The LLVM Compiler Infrastructure |
| 4 | // |
| 5 | // This file was developed by the LLVM research group and is distributed under |
| 6 | // the University of Illinois Open Source License. See LICENSE.TXT for details. |
| 7 | // |
| 8 | //===----------------------------------------------------------------------===// |
Chris Lattner | 8a2a311 | 2001-12-14 16:52:21 +0000 | [diff] [blame] | 9 | // |
| 10 | // InstructionCombining - Combine instructions to form fewer, simple |
Chris Lattner | 62b14df | 2002-09-02 04:59:56 +0000 | [diff] [blame] | 11 | // instructions. This pass does not modify the CFG This pass is where algebraic |
| 12 | // simplification happens. |
Chris Lattner | 8a2a311 | 2001-12-14 16:52:21 +0000 | [diff] [blame] | 13 | // |
| 14 | // This pass combines things like: |
| 15 | // %Y = add int 1, %X |
| 16 | // %Z = add int 1, %Y |
| 17 | // into: |
| 18 | // %Z = add int 2, %X |
| 19 | // |
| 20 | // This is a simple worklist driven algorithm. |
| 21 | // |
Chris Lattner | 065a616 | 2003-09-10 05:29:43 +0000 | [diff] [blame] | 22 | // This pass guarantees that the following canonicalizations are performed on |
Chris Lattner | 2cd9196 | 2003-07-23 21:41:57 +0000 | [diff] [blame] | 23 | // the program: |
| 24 | // 1. If a binary operator has a constant operand, it is moved to the RHS |
Chris Lattner | df17af1 | 2003-08-12 21:53:41 +0000 | [diff] [blame] | 25 | // 2. Bitwise operators with constant operands are always grouped so that |
| 26 | // shifts are performed first, then or's, then and's, then xor's. |
Chris Lattner | 2cd9196 | 2003-07-23 21:41:57 +0000 | [diff] [blame] | 27 | // 3. SetCC instructions are converted from <,>,<=,>= to ==,!= if possible |
| 28 | // 4. All SetCC instructions on boolean values are replaced with logical ops |
Chris Lattner | e92d2f4 | 2003-08-13 04:18:28 +0000 | [diff] [blame] | 29 | // 5. add X, X is represented as (X*2) => (X << 1) |
| 30 | // 6. Multiplies with a power-of-two constant argument are transformed into |
| 31 | // shifts. |
Chris Lattner | 2cd9196 | 2003-07-23 21:41:57 +0000 | [diff] [blame] | 32 | // N. This list is incomplete |
| 33 | // |
Chris Lattner | 8a2a311 | 2001-12-14 16:52:21 +0000 | [diff] [blame] | 34 | //===----------------------------------------------------------------------===// |
| 35 | |
Chris Lattner | 022103b | 2002-05-07 20:03:00 +0000 | [diff] [blame] | 36 | #include "llvm/Transforms/Scalar.h" |
Chris Lattner | c54e2b8 | 2003-05-22 19:07:21 +0000 | [diff] [blame] | 37 | #include "llvm/Instructions.h" |
Chris Lattner | bd0ef77 | 2002-02-26 21:46:54 +0000 | [diff] [blame] | 38 | #include "llvm/Pass.h" |
Chris Lattner | 2a9c847 | 2003-05-27 16:40:51 +0000 | [diff] [blame] | 39 | #include "llvm/Constants.h" |
| 40 | #include "llvm/ConstantHandling.h" |
Chris Lattner | 0864acf | 2002-11-04 16:18:53 +0000 | [diff] [blame] | 41 | #include "llvm/DerivedTypes.h" |
Chris Lattner | 833b8a4 | 2003-06-26 05:06:25 +0000 | [diff] [blame] | 42 | #include "llvm/GlobalVariable.h" |
Chris Lattner | bc61e66 | 2003-11-02 05:57:39 +0000 | [diff] [blame] | 43 | #include "llvm/Target/TargetData.h" |
| 44 | #include "llvm/Transforms/Utils/BasicBlockUtils.h" |
| 45 | #include "llvm/Transforms/Utils/Local.h" |
Chris Lattner | 221d688 | 2002-02-12 21:07:25 +0000 | [diff] [blame] | 46 | #include "llvm/Support/InstIterator.h" |
Chris Lattner | dd841ae | 2002-04-18 17:39:14 +0000 | [diff] [blame] | 47 | #include "llvm/Support/InstVisitor.h" |
Chris Lattner | 9fe3886 | 2003-06-19 17:00:31 +0000 | [diff] [blame] | 48 | #include "llvm/Support/CallSite.h" |
Chris Lattner | a92f696 | 2002-10-01 22:38:41 +0000 | [diff] [blame] | 49 | #include "Support/Statistic.h" |
Chris Lattner | b3bc8fa | 2002-05-14 15:24:07 +0000 | [diff] [blame] | 50 | #include <algorithm> |
Chris Lattner | 8a2a311 | 2001-12-14 16:52:21 +0000 | [diff] [blame] | 51 | |
Chris Lattner | dd841ae | 2002-04-18 17:39:14 +0000 | [diff] [blame] | 52 | namespace { |
Chris Lattner | a92f696 | 2002-10-01 22:38:41 +0000 | [diff] [blame] | 53 | Statistic<> NumCombined ("instcombine", "Number of insts combined"); |
| 54 | Statistic<> NumConstProp("instcombine", "Number of constant folds"); |
| 55 | Statistic<> NumDeadInst ("instcombine", "Number of dead inst eliminated"); |
| 56 | |
Chris Lattner | f57b845 | 2002-04-27 06:56:12 +0000 | [diff] [blame] | 57 | class InstCombiner : public FunctionPass, |
Chris Lattner | dd841ae | 2002-04-18 17:39:14 +0000 | [diff] [blame] | 58 | public InstVisitor<InstCombiner, Instruction*> { |
| 59 | // Worklist of all of the instructions that need to be simplified. |
| 60 | std::vector<Instruction*> WorkList; |
Chris Lattner | bc61e66 | 2003-11-02 05:57:39 +0000 | [diff] [blame] | 61 | TargetData *TD; |
Chris Lattner | dd841ae | 2002-04-18 17:39:14 +0000 | [diff] [blame] | 62 | |
Chris Lattner | 7e70829 | 2002-06-25 16:13:24 +0000 | [diff] [blame] | 63 | void AddUsesToWorkList(Instruction &I) { |
Chris Lattner | dd841ae | 2002-04-18 17:39:14 +0000 | [diff] [blame] | 64 | // The instruction was simplified, add all users of the instruction to |
| 65 | // the work lists because they might get more simplified now... |
| 66 | // |
Chris Lattner | 7e70829 | 2002-06-25 16:13:24 +0000 | [diff] [blame] | 67 | for (Value::use_iterator UI = I.use_begin(), UE = I.use_end(); |
Chris Lattner | dd841ae | 2002-04-18 17:39:14 +0000 | [diff] [blame] | 68 | UI != UE; ++UI) |
| 69 | WorkList.push_back(cast<Instruction>(*UI)); |
| 70 | } |
| 71 | |
Chris Lattner | 62b14df | 2002-09-02 04:59:56 +0000 | [diff] [blame] | 72 | // removeFromWorkList - remove all instances of I from the worklist. |
| 73 | void removeFromWorkList(Instruction *I); |
Chris Lattner | dd841ae | 2002-04-18 17:39:14 +0000 | [diff] [blame] | 74 | public: |
Chris Lattner | 7e70829 | 2002-06-25 16:13:24 +0000 | [diff] [blame] | 75 | virtual bool runOnFunction(Function &F); |
Chris Lattner | dd841ae | 2002-04-18 17:39:14 +0000 | [diff] [blame] | 76 | |
Chris Lattner | 97e52e4 | 2002-04-28 21:27:06 +0000 | [diff] [blame] | 77 | virtual void getAnalysisUsage(AnalysisUsage &AU) const { |
Chris Lattner | bc61e66 | 2003-11-02 05:57:39 +0000 | [diff] [blame] | 78 | AU.addRequired<TargetData>(); |
Chris Lattner | cb2610e | 2002-10-21 20:00:28 +0000 | [diff] [blame] | 79 | AU.setPreservesCFG(); |
Chris Lattner | 97e52e4 | 2002-04-28 21:27:06 +0000 | [diff] [blame] | 80 | } |
| 81 | |
Chris Lattner | dd841ae | 2002-04-18 17:39:14 +0000 | [diff] [blame] | 82 | // Visitation implementation - Implement instruction combining for different |
| 83 | // instruction types. The semantics are as follows: |
| 84 | // Return Value: |
| 85 | // null - No change was made |
Chris Lattner | 233f7dc | 2002-08-12 21:17:25 +0000 | [diff] [blame] | 86 | // I - Change was made, I is still valid, I may be dead though |
Chris Lattner | dd841ae | 2002-04-18 17:39:14 +0000 | [diff] [blame] | 87 | // otherwise - Change was made, replace I with returned instruction |
| 88 | // |
Chris Lattner | 7e70829 | 2002-06-25 16:13:24 +0000 | [diff] [blame] | 89 | Instruction *visitAdd(BinaryOperator &I); |
| 90 | Instruction *visitSub(BinaryOperator &I); |
| 91 | Instruction *visitMul(BinaryOperator &I); |
| 92 | Instruction *visitDiv(BinaryOperator &I); |
| 93 | Instruction *visitRem(BinaryOperator &I); |
| 94 | Instruction *visitAnd(BinaryOperator &I); |
| 95 | Instruction *visitOr (BinaryOperator &I); |
| 96 | Instruction *visitXor(BinaryOperator &I); |
| 97 | Instruction *visitSetCondInst(BinaryOperator &I); |
Chris Lattner | ea34005 | 2003-03-10 19:16:08 +0000 | [diff] [blame] | 98 | Instruction *visitShiftInst(ShiftInst &I); |
Chris Lattner | 7e70829 | 2002-06-25 16:13:24 +0000 | [diff] [blame] | 99 | Instruction *visitCastInst(CastInst &CI); |
Chris Lattner | 9fe3886 | 2003-06-19 17:00:31 +0000 | [diff] [blame] | 100 | Instruction *visitCallInst(CallInst &CI); |
| 101 | Instruction *visitInvokeInst(InvokeInst &II); |
Chris Lattner | 7e70829 | 2002-06-25 16:13:24 +0000 | [diff] [blame] | 102 | Instruction *visitPHINode(PHINode &PN); |
| 103 | Instruction *visitGetElementPtrInst(GetElementPtrInst &GEP); |
Chris Lattner | 0864acf | 2002-11-04 16:18:53 +0000 | [diff] [blame] | 104 | Instruction *visitAllocationInst(AllocationInst &AI); |
Chris Lattner | 833b8a4 | 2003-06-26 05:06:25 +0000 | [diff] [blame] | 105 | Instruction *visitLoadInst(LoadInst &LI); |
Chris Lattner | c4d10eb | 2003-06-04 04:46:00 +0000 | [diff] [blame] | 106 | Instruction *visitBranchInst(BranchInst &BI); |
Chris Lattner | dd841ae | 2002-04-18 17:39:14 +0000 | [diff] [blame] | 107 | |
| 108 | // visitInstruction - Specify what to return for unhandled instructions... |
Chris Lattner | 7e70829 | 2002-06-25 16:13:24 +0000 | [diff] [blame] | 109 | Instruction *visitInstruction(Instruction &I) { return 0; } |
Chris Lattner | 8b17094 | 2002-08-09 23:47:40 +0000 | [diff] [blame] | 110 | |
Chris Lattner | 9fe3886 | 2003-06-19 17:00:31 +0000 | [diff] [blame] | 111 | private: |
Chris Lattner | a44d8a2 | 2003-10-07 22:32:43 +0000 | [diff] [blame] | 112 | Instruction *visitCallSite(CallSite CS); |
Chris Lattner | 9fe3886 | 2003-06-19 17:00:31 +0000 | [diff] [blame] | 113 | bool transformConstExprCastCall(CallSite CS); |
| 114 | |
Chris Lattner | 8b17094 | 2002-08-09 23:47:40 +0000 | [diff] [blame] | 115 | // InsertNewInstBefore - insert an instruction New before instruction Old |
| 116 | // in the program. Add the new instruction to the worklist. |
| 117 | // |
| 118 | void InsertNewInstBefore(Instruction *New, Instruction &Old) { |
Chris Lattner | e6f9a91 | 2002-08-23 18:32:43 +0000 | [diff] [blame] | 119 | assert(New && New->getParent() == 0 && |
| 120 | "New instruction already inserted into a basic block!"); |
Chris Lattner | 8b17094 | 2002-08-09 23:47:40 +0000 | [diff] [blame] | 121 | BasicBlock *BB = Old.getParent(); |
| 122 | BB->getInstList().insert(&Old, New); // Insert inst |
| 123 | WorkList.push_back(New); // Add to worklist |
| 124 | } |
| 125 | |
Chris Lattner | aa9c1f1 | 2003-08-13 20:16:26 +0000 | [diff] [blame] | 126 | public: |
Chris Lattner | 8b17094 | 2002-08-09 23:47:40 +0000 | [diff] [blame] | 127 | // ReplaceInstUsesWith - This method is to be used when an instruction is |
| 128 | // found to be dead, replacable with another preexisting expression. Here |
| 129 | // we add all uses of I to the worklist, replace all uses of I with the new |
| 130 | // value, then return I, so that the inst combiner will know that I was |
| 131 | // modified. |
| 132 | // |
| 133 | Instruction *ReplaceInstUsesWith(Instruction &I, Value *V) { |
| 134 | AddUsesToWorkList(I); // Add all modified instrs to worklist |
| 135 | I.replaceAllUsesWith(V); |
| 136 | return &I; |
| 137 | } |
Chris Lattner | aa9c1f1 | 2003-08-13 20:16:26 +0000 | [diff] [blame] | 138 | private: |
Chris Lattner | 24c8e38 | 2003-07-24 17:35:25 +0000 | [diff] [blame] | 139 | /// InsertOperandCastBefore - This inserts a cast of V to DestTy before the |
| 140 | /// InsertBefore instruction. This is specialized a bit to avoid inserting |
| 141 | /// casts that are known to not do anything... |
| 142 | /// |
| 143 | Value *InsertOperandCastBefore(Value *V, const Type *DestTy, |
| 144 | Instruction *InsertBefore); |
| 145 | |
Chris Lattner | c8802d2 | 2003-03-11 00:12:48 +0000 | [diff] [blame] | 146 | // SimplifyCommutative - This performs a few simplifications for commutative |
| 147 | // operators... |
| 148 | bool SimplifyCommutative(BinaryOperator &I); |
Chris Lattner | bd7b5ff | 2003-09-19 17:17:26 +0000 | [diff] [blame] | 149 | |
| 150 | Instruction *OptAndOp(Instruction *Op, ConstantIntegral *OpRHS, |
| 151 | ConstantIntegral *AndRHS, BinaryOperator &TheAnd); |
Chris Lattner | dd841ae | 2002-04-18 17:39:14 +0000 | [diff] [blame] | 152 | }; |
Chris Lattner | f629309 | 2002-07-23 18:06:35 +0000 | [diff] [blame] | 153 | |
Chris Lattner | a6275cc | 2002-07-26 21:12:46 +0000 | [diff] [blame] | 154 | RegisterOpt<InstCombiner> X("instcombine", "Combine redundant instructions"); |
Chris Lattner | dd841ae | 2002-04-18 17:39:14 +0000 | [diff] [blame] | 155 | } |
| 156 | |
Chris Lattner | 4f98c56 | 2003-03-10 21:43:22 +0000 | [diff] [blame] | 157 | // getComplexity: Assign a complexity or rank value to LLVM Values... |
| 158 | // 0 -> Constant, 1 -> Other, 2 -> Argument, 2 -> Unary, 3 -> OtherInst |
| 159 | static unsigned getComplexity(Value *V) { |
| 160 | if (isa<Instruction>(V)) { |
| 161 | if (BinaryOperator::isNeg(V) || BinaryOperator::isNot(V)) |
| 162 | return 2; |
| 163 | return 3; |
| 164 | } |
| 165 | if (isa<Argument>(V)) return 2; |
| 166 | return isa<Constant>(V) ? 0 : 1; |
| 167 | } |
Chris Lattner | dd841ae | 2002-04-18 17:39:14 +0000 | [diff] [blame] | 168 | |
Chris Lattner | c8802d2 | 2003-03-11 00:12:48 +0000 | [diff] [blame] | 169 | // isOnlyUse - Return true if this instruction will be deleted if we stop using |
| 170 | // it. |
| 171 | static bool isOnlyUse(Value *V) { |
Chris Lattner | fd05924 | 2003-10-15 16:48:29 +0000 | [diff] [blame] | 172 | return V->hasOneUse() || isa<Constant>(V); |
Chris Lattner | c8802d2 | 2003-03-11 00:12:48 +0000 | [diff] [blame] | 173 | } |
| 174 | |
Chris Lattner | 4f98c56 | 2003-03-10 21:43:22 +0000 | [diff] [blame] | 175 | // SimplifyCommutative - This performs a few simplifications for commutative |
| 176 | // operators: |
Chris Lattner | dd841ae | 2002-04-18 17:39:14 +0000 | [diff] [blame] | 177 | // |
Chris Lattner | 4f98c56 | 2003-03-10 21:43:22 +0000 | [diff] [blame] | 178 | // 1. Order operands such that they are listed from right (least complex) to |
| 179 | // left (most complex). This puts constants before unary operators before |
| 180 | // binary operators. |
| 181 | // |
Chris Lattner | c8802d2 | 2003-03-11 00:12:48 +0000 | [diff] [blame] | 182 | // 2. Transform: (op (op V, C1), C2) ==> (op V, (op C1, C2)) |
| 183 | // 3. Transform: (op (op V1, C1), (op V2, C2)) ==> (op (op V1, V2), (op C1,C2)) |
Chris Lattner | 4f98c56 | 2003-03-10 21:43:22 +0000 | [diff] [blame] | 184 | // |
Chris Lattner | c8802d2 | 2003-03-11 00:12:48 +0000 | [diff] [blame] | 185 | bool InstCombiner::SimplifyCommutative(BinaryOperator &I) { |
Chris Lattner | 4f98c56 | 2003-03-10 21:43:22 +0000 | [diff] [blame] | 186 | bool Changed = false; |
| 187 | if (getComplexity(I.getOperand(0)) < getComplexity(I.getOperand(1))) |
| 188 | Changed = !I.swapOperands(); |
| 189 | |
| 190 | if (!I.isAssociative()) return Changed; |
| 191 | Instruction::BinaryOps Opcode = I.getOpcode(); |
Chris Lattner | c8802d2 | 2003-03-11 00:12:48 +0000 | [diff] [blame] | 192 | if (BinaryOperator *Op = dyn_cast<BinaryOperator>(I.getOperand(0))) |
| 193 | if (Op->getOpcode() == Opcode && isa<Constant>(Op->getOperand(1))) { |
| 194 | if (isa<Constant>(I.getOperand(1))) { |
Chris Lattner | 2a9c847 | 2003-05-27 16:40:51 +0000 | [diff] [blame] | 195 | Constant *Folded = ConstantExpr::get(I.getOpcode(), |
| 196 | cast<Constant>(I.getOperand(1)), |
| 197 | cast<Constant>(Op->getOperand(1))); |
Chris Lattner | c8802d2 | 2003-03-11 00:12:48 +0000 | [diff] [blame] | 198 | I.setOperand(0, Op->getOperand(0)); |
| 199 | I.setOperand(1, Folded); |
| 200 | return true; |
| 201 | } else if (BinaryOperator *Op1=dyn_cast<BinaryOperator>(I.getOperand(1))) |
| 202 | if (Op1->getOpcode() == Opcode && isa<Constant>(Op1->getOperand(1)) && |
| 203 | isOnlyUse(Op) && isOnlyUse(Op1)) { |
| 204 | Constant *C1 = cast<Constant>(Op->getOperand(1)); |
| 205 | Constant *C2 = cast<Constant>(Op1->getOperand(1)); |
| 206 | |
| 207 | // Fold (op (op V1, C1), (op V2, C2)) ==> (op (op V1, V2), (op C1,C2)) |
Chris Lattner | 2a9c847 | 2003-05-27 16:40:51 +0000 | [diff] [blame] | 208 | Constant *Folded = ConstantExpr::get(I.getOpcode(), C1, C2); |
Chris Lattner | c8802d2 | 2003-03-11 00:12:48 +0000 | [diff] [blame] | 209 | Instruction *New = BinaryOperator::create(Opcode, Op->getOperand(0), |
| 210 | Op1->getOperand(0), |
| 211 | Op1->getName(), &I); |
| 212 | WorkList.push_back(New); |
| 213 | I.setOperand(0, New); |
| 214 | I.setOperand(1, Folded); |
| 215 | return true; |
| 216 | } |
Chris Lattner | 4f98c56 | 2003-03-10 21:43:22 +0000 | [diff] [blame] | 217 | } |
Chris Lattner | 4f98c56 | 2003-03-10 21:43:22 +0000 | [diff] [blame] | 218 | return Changed; |
Chris Lattner | dd841ae | 2002-04-18 17:39:14 +0000 | [diff] [blame] | 219 | } |
Chris Lattner | 8a2a311 | 2001-12-14 16:52:21 +0000 | [diff] [blame] | 220 | |
Chris Lattner | 8d96964 | 2003-03-10 23:06:50 +0000 | [diff] [blame] | 221 | // dyn_castNegVal - Given a 'sub' instruction, return the RHS of the instruction |
| 222 | // if the LHS is a constant zero (which is the 'negate' form). |
Chris Lattner | b35dde1 | 2002-05-06 16:49:18 +0000 | [diff] [blame] | 223 | // |
Chris Lattner | 8d96964 | 2003-03-10 23:06:50 +0000 | [diff] [blame] | 224 | static inline Value *dyn_castNegVal(Value *V) { |
| 225 | if (BinaryOperator::isNeg(V)) |
| 226 | return BinaryOperator::getNegArgument(cast<BinaryOperator>(V)); |
| 227 | |
Chris Lattner | fe32e0c | 2003-04-30 22:19:10 +0000 | [diff] [blame] | 228 | // Constants can be considered to be negated values if they can be folded... |
| 229 | if (Constant *C = dyn_cast<Constant>(V)) |
Chris Lattner | 2a9c847 | 2003-05-27 16:40:51 +0000 | [diff] [blame] | 230 | return ConstantExpr::get(Instruction::Sub, |
| 231 | Constant::getNullValue(V->getType()), C); |
Chris Lattner | 8d96964 | 2003-03-10 23:06:50 +0000 | [diff] [blame] | 232 | return 0; |
Chris Lattner | b35dde1 | 2002-05-06 16:49:18 +0000 | [diff] [blame] | 233 | } |
| 234 | |
Chris Lattner | 8d96964 | 2003-03-10 23:06:50 +0000 | [diff] [blame] | 235 | static inline Value *dyn_castNotVal(Value *V) { |
| 236 | if (BinaryOperator::isNot(V)) |
| 237 | return BinaryOperator::getNotArgument(cast<BinaryOperator>(V)); |
| 238 | |
| 239 | // Constants can be considered to be not'ed values... |
Chris Lattner | 3f2ec39 | 2003-04-30 22:34:06 +0000 | [diff] [blame] | 240 | if (ConstantIntegral *C = dyn_cast<ConstantIntegral>(V)) |
Chris Lattner | 2a9c847 | 2003-05-27 16:40:51 +0000 | [diff] [blame] | 241 | return ConstantExpr::get(Instruction::Xor, |
| 242 | ConstantIntegral::getAllOnesValue(C->getType()),C); |
Chris Lattner | 8d96964 | 2003-03-10 23:06:50 +0000 | [diff] [blame] | 243 | return 0; |
| 244 | } |
| 245 | |
Chris Lattner | c8802d2 | 2003-03-11 00:12:48 +0000 | [diff] [blame] | 246 | // dyn_castFoldableMul - If this value is a multiply that can be folded into |
| 247 | // other computations (because it has a constant operand), return the |
| 248 | // non-constant operand of the multiply. |
| 249 | // |
| 250 | static inline Value *dyn_castFoldableMul(Value *V) { |
Chris Lattner | fd05924 | 2003-10-15 16:48:29 +0000 | [diff] [blame] | 251 | if (V->hasOneUse() && V->getType()->isInteger()) |
Chris Lattner | c8802d2 | 2003-03-11 00:12:48 +0000 | [diff] [blame] | 252 | if (Instruction *I = dyn_cast<Instruction>(V)) |
| 253 | if (I->getOpcode() == Instruction::Mul) |
| 254 | if (isa<Constant>(I->getOperand(1))) |
| 255 | return I->getOperand(0); |
| 256 | return 0; |
Chris Lattner | a288196 | 2003-02-18 19:28:33 +0000 | [diff] [blame] | 257 | } |
Chris Lattner | af2930e | 2002-08-14 17:51:49 +0000 | [diff] [blame] | 258 | |
Chris Lattner | c8802d2 | 2003-03-11 00:12:48 +0000 | [diff] [blame] | 259 | // dyn_castMaskingAnd - If this value is an And instruction masking a value with |
| 260 | // a constant, return the constant being anded with. |
| 261 | // |
Chris Lattner | e132d95 | 2003-08-12 19:17:27 +0000 | [diff] [blame] | 262 | template<class ValueType> |
| 263 | static inline Constant *dyn_castMaskingAnd(ValueType *V) { |
Chris Lattner | c8802d2 | 2003-03-11 00:12:48 +0000 | [diff] [blame] | 264 | if (Instruction *I = dyn_cast<Instruction>(V)) |
| 265 | if (I->getOpcode() == Instruction::And) |
| 266 | return dyn_cast<Constant>(I->getOperand(1)); |
| 267 | |
| 268 | // If this is a constant, it acts just like we were masking with it. |
| 269 | return dyn_cast<Constant>(V); |
| 270 | } |
Chris Lattner | a288196 | 2003-02-18 19:28:33 +0000 | [diff] [blame] | 271 | |
| 272 | // Log2 - Calculate the log base 2 for the specified value if it is exactly a |
| 273 | // power of 2. |
| 274 | static unsigned Log2(uint64_t Val) { |
| 275 | assert(Val > 1 && "Values 0 and 1 should be handled elsewhere!"); |
| 276 | unsigned Count = 0; |
| 277 | while (Val != 1) { |
| 278 | if (Val & 1) return 0; // Multiple bits set? |
| 279 | Val >>= 1; |
| 280 | ++Count; |
| 281 | } |
| 282 | return Count; |
Chris Lattner | af2930e | 2002-08-14 17:51:49 +0000 | [diff] [blame] | 283 | } |
| 284 | |
Chris Lattner | 564a727 | 2003-08-13 19:01:45 +0000 | [diff] [blame] | 285 | |
| 286 | /// AssociativeOpt - Perform an optimization on an associative operator. This |
| 287 | /// function is designed to check a chain of associative operators for a |
| 288 | /// potential to apply a certain optimization. Since the optimization may be |
| 289 | /// applicable if the expression was reassociated, this checks the chain, then |
| 290 | /// reassociates the expression as necessary to expose the optimization |
| 291 | /// opportunity. This makes use of a special Functor, which must define |
| 292 | /// 'shouldApply' and 'apply' methods. |
| 293 | /// |
| 294 | template<typename Functor> |
| 295 | Instruction *AssociativeOpt(BinaryOperator &Root, const Functor &F) { |
| 296 | unsigned Opcode = Root.getOpcode(); |
| 297 | Value *LHS = Root.getOperand(0); |
| 298 | |
| 299 | // Quick check, see if the immediate LHS matches... |
| 300 | if (F.shouldApply(LHS)) |
| 301 | return F.apply(Root); |
| 302 | |
| 303 | // Otherwise, if the LHS is not of the same opcode as the root, return. |
| 304 | Instruction *LHSI = dyn_cast<Instruction>(LHS); |
Chris Lattner | fd05924 | 2003-10-15 16:48:29 +0000 | [diff] [blame] | 305 | while (LHSI && LHSI->getOpcode() == Opcode && LHSI->hasOneUse()) { |
Chris Lattner | 564a727 | 2003-08-13 19:01:45 +0000 | [diff] [blame] | 306 | // Should we apply this transform to the RHS? |
| 307 | bool ShouldApply = F.shouldApply(LHSI->getOperand(1)); |
| 308 | |
| 309 | // If not to the RHS, check to see if we should apply to the LHS... |
| 310 | if (!ShouldApply && F.shouldApply(LHSI->getOperand(0))) { |
| 311 | cast<BinaryOperator>(LHSI)->swapOperands(); // Make the LHS the RHS |
| 312 | ShouldApply = true; |
| 313 | } |
| 314 | |
| 315 | // If the functor wants to apply the optimization to the RHS of LHSI, |
| 316 | // reassociate the expression from ((? op A) op B) to (? op (A op B)) |
| 317 | if (ShouldApply) { |
| 318 | BasicBlock *BB = Root.getParent(); |
| 319 | // All of the instructions have a single use and have no side-effects, |
| 320 | // because of this, we can pull them all into the current basic block. |
| 321 | if (LHSI->getParent() != BB) { |
| 322 | // Move all of the instructions from root to LHSI into the current |
| 323 | // block. |
| 324 | Instruction *TmpLHSI = cast<Instruction>(Root.getOperand(0)); |
| 325 | Instruction *LastUse = &Root; |
| 326 | while (TmpLHSI->getParent() == BB) { |
| 327 | LastUse = TmpLHSI; |
| 328 | TmpLHSI = cast<Instruction>(TmpLHSI->getOperand(0)); |
| 329 | } |
| 330 | |
| 331 | // Loop over all of the instructions in other blocks, moving them into |
| 332 | // the current one. |
| 333 | Value *TmpLHS = TmpLHSI; |
| 334 | do { |
| 335 | TmpLHSI = cast<Instruction>(TmpLHS); |
| 336 | // Remove from current block... |
| 337 | TmpLHSI->getParent()->getInstList().remove(TmpLHSI); |
| 338 | // Insert before the last instruction... |
| 339 | BB->getInstList().insert(LastUse, TmpLHSI); |
| 340 | TmpLHS = TmpLHSI->getOperand(0); |
| 341 | } while (TmpLHSI != LHSI); |
| 342 | } |
| 343 | |
| 344 | // Now all of the instructions are in the current basic block, go ahead |
| 345 | // and perform the reassociation. |
| 346 | Instruction *TmpLHSI = cast<Instruction>(Root.getOperand(0)); |
| 347 | |
| 348 | // First move the selected RHS to the LHS of the root... |
| 349 | Root.setOperand(0, LHSI->getOperand(1)); |
| 350 | |
| 351 | // Make what used to be the LHS of the root be the user of the root... |
| 352 | Value *ExtraOperand = TmpLHSI->getOperand(1); |
| 353 | Root.replaceAllUsesWith(TmpLHSI); // Users now use TmpLHSI |
| 354 | TmpLHSI->setOperand(1, &Root); // TmpLHSI now uses the root |
| 355 | BB->getInstList().remove(&Root); // Remove root from the BB |
| 356 | BB->getInstList().insert(TmpLHSI, &Root); // Insert root before TmpLHSI |
| 357 | |
| 358 | // Now propagate the ExtraOperand down the chain of instructions until we |
| 359 | // get to LHSI. |
| 360 | while (TmpLHSI != LHSI) { |
| 361 | Instruction *NextLHSI = cast<Instruction>(TmpLHSI->getOperand(0)); |
| 362 | Value *NextOp = NextLHSI->getOperand(1); |
| 363 | NextLHSI->setOperand(1, ExtraOperand); |
| 364 | TmpLHSI = NextLHSI; |
| 365 | ExtraOperand = NextOp; |
| 366 | } |
| 367 | |
| 368 | // Now that the instructions are reassociated, have the functor perform |
| 369 | // the transformation... |
| 370 | return F.apply(Root); |
| 371 | } |
| 372 | |
| 373 | LHSI = dyn_cast<Instruction>(LHSI->getOperand(0)); |
| 374 | } |
| 375 | return 0; |
| 376 | } |
| 377 | |
| 378 | |
| 379 | // AddRHS - Implements: X + X --> X << 1 |
| 380 | struct AddRHS { |
| 381 | Value *RHS; |
| 382 | AddRHS(Value *rhs) : RHS(rhs) {} |
| 383 | bool shouldApply(Value *LHS) const { return LHS == RHS; } |
| 384 | Instruction *apply(BinaryOperator &Add) const { |
| 385 | return new ShiftInst(Instruction::Shl, Add.getOperand(0), |
| 386 | ConstantInt::get(Type::UByteTy, 1)); |
| 387 | } |
| 388 | }; |
| 389 | |
| 390 | // AddMaskingAnd - Implements (A & C1)+(B & C2) --> (A & C1)|(B & C2) |
| 391 | // iff C1&C2 == 0 |
| 392 | struct AddMaskingAnd { |
| 393 | Constant *C2; |
| 394 | AddMaskingAnd(Constant *c) : C2(c) {} |
| 395 | bool shouldApply(Value *LHS) const { |
| 396 | if (Constant *C1 = dyn_castMaskingAnd(LHS)) |
| 397 | return ConstantExpr::get(Instruction::And, C1, C2)->isNullValue(); |
| 398 | return false; |
| 399 | } |
| 400 | Instruction *apply(BinaryOperator &Add) const { |
| 401 | return BinaryOperator::create(Instruction::Or, Add.getOperand(0), |
| 402 | Add.getOperand(1)); |
| 403 | } |
| 404 | }; |
| 405 | |
| 406 | |
| 407 | |
Chris Lattner | 7e70829 | 2002-06-25 16:13:24 +0000 | [diff] [blame] | 408 | Instruction *InstCombiner::visitAdd(BinaryOperator &I) { |
Chris Lattner | 4f98c56 | 2003-03-10 21:43:22 +0000 | [diff] [blame] | 409 | bool Changed = SimplifyCommutative(I); |
Chris Lattner | 7e70829 | 2002-06-25 16:13:24 +0000 | [diff] [blame] | 410 | Value *LHS = I.getOperand(0), *RHS = I.getOperand(1); |
Chris Lattner | b35dde1 | 2002-05-06 16:49:18 +0000 | [diff] [blame] | 411 | |
Chris Lattner | 564a727 | 2003-08-13 19:01:45 +0000 | [diff] [blame] | 412 | // X + 0 --> X |
Chris Lattner | 233f7dc | 2002-08-12 21:17:25 +0000 | [diff] [blame] | 413 | if (RHS == Constant::getNullValue(I.getType())) |
| 414 | return ReplaceInstUsesWith(I, LHS); |
Chris Lattner | b35dde1 | 2002-05-06 16:49:18 +0000 | [diff] [blame] | 415 | |
Chris Lattner | 564a727 | 2003-08-13 19:01:45 +0000 | [diff] [blame] | 416 | // X + X --> X << 1 |
| 417 | if (I.getType()->isInteger()) |
| 418 | if (Instruction *Result = AssociativeOpt(I, AddRHS(RHS))) return Result; |
Chris Lattner | e92d2f4 | 2003-08-13 04:18:28 +0000 | [diff] [blame] | 419 | |
Chris Lattner | 5c4afb9 | 2002-05-08 22:46:53 +0000 | [diff] [blame] | 420 | // -A + B --> B - A |
Chris Lattner | 8d96964 | 2003-03-10 23:06:50 +0000 | [diff] [blame] | 421 | if (Value *V = dyn_castNegVal(LHS)) |
Chris Lattner | 5c4afb9 | 2002-05-08 22:46:53 +0000 | [diff] [blame] | 422 | return BinaryOperator::create(Instruction::Sub, RHS, V); |
Chris Lattner | b35dde1 | 2002-05-06 16:49:18 +0000 | [diff] [blame] | 423 | |
| 424 | // A + -B --> A - B |
Chris Lattner | 8d96964 | 2003-03-10 23:06:50 +0000 | [diff] [blame] | 425 | if (!isa<Constant>(RHS)) |
| 426 | if (Value *V = dyn_castNegVal(RHS)) |
| 427 | return BinaryOperator::create(Instruction::Sub, LHS, V); |
Chris Lattner | dd841ae | 2002-04-18 17:39:14 +0000 | [diff] [blame] | 428 | |
Chris Lattner | ad3448c | 2003-02-18 19:57:07 +0000 | [diff] [blame] | 429 | // X*C + X --> X * (C+1) |
| 430 | if (dyn_castFoldableMul(LHS) == RHS) { |
Chris Lattner | 2a9c847 | 2003-05-27 16:40:51 +0000 | [diff] [blame] | 431 | Constant *CP1 = |
| 432 | ConstantExpr::get(Instruction::Add, |
| 433 | cast<Constant>(cast<Instruction>(LHS)->getOperand(1)), |
| 434 | ConstantInt::get(I.getType(), 1)); |
Chris Lattner | ad3448c | 2003-02-18 19:57:07 +0000 | [diff] [blame] | 435 | return BinaryOperator::create(Instruction::Mul, RHS, CP1); |
| 436 | } |
| 437 | |
| 438 | // X + X*C --> X * (C+1) |
| 439 | if (dyn_castFoldableMul(RHS) == LHS) { |
Chris Lattner | 2a9c847 | 2003-05-27 16:40:51 +0000 | [diff] [blame] | 440 | Constant *CP1 = |
| 441 | ConstantExpr::get(Instruction::Add, |
| 442 | cast<Constant>(cast<Instruction>(RHS)->getOperand(1)), |
| 443 | ConstantInt::get(I.getType(), 1)); |
Chris Lattner | ad3448c | 2003-02-18 19:57:07 +0000 | [diff] [blame] | 444 | return BinaryOperator::create(Instruction::Mul, LHS, CP1); |
| 445 | } |
| 446 | |
Chris Lattner | 564a727 | 2003-08-13 19:01:45 +0000 | [diff] [blame] | 447 | // (A & C1)+(B & C2) --> (A & C1)|(B & C2) iff C1&C2 == 0 |
| 448 | if (Constant *C2 = dyn_castMaskingAnd(RHS)) |
| 449 | if (Instruction *R = AssociativeOpt(I, AddMaskingAnd(C2))) return R; |
Chris Lattner | c8802d2 | 2003-03-11 00:12:48 +0000 | [diff] [blame] | 450 | |
Chris Lattner | 6b03205 | 2003-10-02 15:11:26 +0000 | [diff] [blame] | 451 | if (ConstantInt *CRHS = dyn_cast<ConstantInt>(RHS)) { |
| 452 | if (Instruction *ILHS = dyn_cast<Instruction>(LHS)) { |
| 453 | switch (ILHS->getOpcode()) { |
| 454 | case Instruction::Xor: |
| 455 | // ~X + C --> (C-1) - X |
| 456 | if (ConstantInt *XorRHS = dyn_cast<ConstantInt>(ILHS->getOperand(1))) |
| 457 | if (XorRHS->isAllOnesValue()) |
| 458 | return BinaryOperator::create(Instruction::Sub, |
| 459 | *CRHS - *ConstantInt::get(I.getType(), 1), |
| 460 | ILHS->getOperand(0)); |
| 461 | break; |
| 462 | default: break; |
| 463 | } |
| 464 | } |
| 465 | } |
| 466 | |
Chris Lattner | 7e70829 | 2002-06-25 16:13:24 +0000 | [diff] [blame] | 467 | return Changed ? &I : 0; |
Chris Lattner | dd841ae | 2002-04-18 17:39:14 +0000 | [diff] [blame] | 468 | } |
| 469 | |
Chris Lattner | 1ba5bcd | 2003-07-22 21:46:59 +0000 | [diff] [blame] | 470 | // isSignBit - Return true if the value represented by the constant only has the |
| 471 | // highest order bit set. |
| 472 | static bool isSignBit(ConstantInt *CI) { |
| 473 | unsigned NumBits = CI->getType()->getPrimitiveSize()*8; |
| 474 | return (CI->getRawValue() & ~(-1LL << NumBits)) == (1ULL << (NumBits-1)); |
| 475 | } |
| 476 | |
Chris Lattner | 24c8e38 | 2003-07-24 17:35:25 +0000 | [diff] [blame] | 477 | static unsigned getTypeSizeInBits(const Type *Ty) { |
| 478 | return Ty == Type::BoolTy ? 1 : Ty->getPrimitiveSize()*8; |
| 479 | } |
| 480 | |
Chris Lattner | 7e70829 | 2002-06-25 16:13:24 +0000 | [diff] [blame] | 481 | Instruction *InstCombiner::visitSub(BinaryOperator &I) { |
Chris Lattner | 7e70829 | 2002-06-25 16:13:24 +0000 | [diff] [blame] | 482 | Value *Op0 = I.getOperand(0), *Op1 = I.getOperand(1); |
Chris Lattner | 3f5b877 | 2002-05-06 16:14:14 +0000 | [diff] [blame] | 483 | |
Chris Lattner | 233f7dc | 2002-08-12 21:17:25 +0000 | [diff] [blame] | 484 | if (Op0 == Op1) // sub X, X -> 0 |
| 485 | return ReplaceInstUsesWith(I, Constant::getNullValue(I.getType())); |
Chris Lattner | dd841ae | 2002-04-18 17:39:14 +0000 | [diff] [blame] | 486 | |
Chris Lattner | 233f7dc | 2002-08-12 21:17:25 +0000 | [diff] [blame] | 487 | // If this is a 'B = x-(-A)', change to B = x+A... |
Chris Lattner | 8d96964 | 2003-03-10 23:06:50 +0000 | [diff] [blame] | 488 | if (Value *V = dyn_castNegVal(Op1)) |
Chris Lattner | 5c4afb9 | 2002-05-08 22:46:53 +0000 | [diff] [blame] | 489 | return BinaryOperator::create(Instruction::Add, Op0, V); |
Chris Lattner | b35dde1 | 2002-05-06 16:49:18 +0000 | [diff] [blame] | 490 | |
Chris Lattner | a288196 | 2003-02-18 19:28:33 +0000 | [diff] [blame] | 491 | // Replace (-1 - A) with (~A)... |
| 492 | if (ConstantInt *C = dyn_cast<ConstantInt>(Op0)) |
| 493 | if (C->isAllOnesValue()) |
| 494 | return BinaryOperator::createNot(Op1); |
Chris Lattner | 4037171 | 2002-05-09 01:29:19 +0000 | [diff] [blame] | 495 | |
Chris Lattner | a288196 | 2003-02-18 19:28:33 +0000 | [diff] [blame] | 496 | if (BinaryOperator *Op1I = dyn_cast<BinaryOperator>(Op1)) |
Chris Lattner | fd05924 | 2003-10-15 16:48:29 +0000 | [diff] [blame] | 497 | if (Op1I->hasOneUse()) { |
Chris Lattner | a288196 | 2003-02-18 19:28:33 +0000 | [diff] [blame] | 498 | // Replace (x - (y - z)) with (x + (z - y)) if the (y - z) subexpression |
| 499 | // is not used by anyone else... |
| 500 | // |
| 501 | if (Op1I->getOpcode() == Instruction::Sub) { |
| 502 | // Swap the two operands of the subexpr... |
| 503 | Value *IIOp0 = Op1I->getOperand(0), *IIOp1 = Op1I->getOperand(1); |
| 504 | Op1I->setOperand(0, IIOp1); |
| 505 | Op1I->setOperand(1, IIOp0); |
| 506 | |
| 507 | // Create the new top level add instruction... |
| 508 | return BinaryOperator::create(Instruction::Add, Op0, Op1); |
| 509 | } |
| 510 | |
| 511 | // Replace (A - (A & B)) with (A & ~B) if this is the only use of (A&B)... |
| 512 | // |
| 513 | if (Op1I->getOpcode() == Instruction::And && |
| 514 | (Op1I->getOperand(0) == Op0 || Op1I->getOperand(1) == Op0)) { |
| 515 | Value *OtherOp = Op1I->getOperand(Op1I->getOperand(0) == Op0); |
| 516 | |
| 517 | Instruction *NewNot = BinaryOperator::createNot(OtherOp, "B.not", &I); |
| 518 | return BinaryOperator::create(Instruction::And, Op0, NewNot); |
| 519 | } |
Chris Lattner | ad3448c | 2003-02-18 19:57:07 +0000 | [diff] [blame] | 520 | |
| 521 | // X - X*C --> X * (1-C) |
| 522 | if (dyn_castFoldableMul(Op1I) == Op0) { |
Chris Lattner | 2a9c847 | 2003-05-27 16:40:51 +0000 | [diff] [blame] | 523 | Constant *CP1 = |
| 524 | ConstantExpr::get(Instruction::Sub, |
| 525 | ConstantInt::get(I.getType(), 1), |
| 526 | cast<Constant>(cast<Instruction>(Op1)->getOperand(1))); |
Chris Lattner | ad3448c | 2003-02-18 19:57:07 +0000 | [diff] [blame] | 527 | assert(CP1 && "Couldn't constant fold 1-C?"); |
| 528 | return BinaryOperator::create(Instruction::Mul, Op0, CP1); |
| 529 | } |
Chris Lattner | 4037171 | 2002-05-09 01:29:19 +0000 | [diff] [blame] | 530 | } |
Chris Lattner | a288196 | 2003-02-18 19:28:33 +0000 | [diff] [blame] | 531 | |
Chris Lattner | ad3448c | 2003-02-18 19:57:07 +0000 | [diff] [blame] | 532 | // X*C - X --> X * (C-1) |
| 533 | if (dyn_castFoldableMul(Op0) == Op1) { |
Chris Lattner | 2a9c847 | 2003-05-27 16:40:51 +0000 | [diff] [blame] | 534 | Constant *CP1 = |
| 535 | ConstantExpr::get(Instruction::Sub, |
| 536 | cast<Constant>(cast<Instruction>(Op0)->getOperand(1)), |
| 537 | ConstantInt::get(I.getType(), 1)); |
Chris Lattner | ad3448c | 2003-02-18 19:57:07 +0000 | [diff] [blame] | 538 | assert(CP1 && "Couldn't constant fold C - 1?"); |
| 539 | return BinaryOperator::create(Instruction::Mul, Op1, CP1); |
| 540 | } |
| 541 | |
Chris Lattner | 3f5b877 | 2002-05-06 16:14:14 +0000 | [diff] [blame] | 542 | return 0; |
Chris Lattner | dd841ae | 2002-04-18 17:39:14 +0000 | [diff] [blame] | 543 | } |
| 544 | |
Chris Lattner | 7e70829 | 2002-06-25 16:13:24 +0000 | [diff] [blame] | 545 | Instruction *InstCombiner::visitMul(BinaryOperator &I) { |
Chris Lattner | 4f98c56 | 2003-03-10 21:43:22 +0000 | [diff] [blame] | 546 | bool Changed = SimplifyCommutative(I); |
Chris Lattner | a288196 | 2003-02-18 19:28:33 +0000 | [diff] [blame] | 547 | Value *Op0 = I.getOperand(0); |
Chris Lattner | dd841ae | 2002-04-18 17:39:14 +0000 | [diff] [blame] | 548 | |
Chris Lattner | 233f7dc | 2002-08-12 21:17:25 +0000 | [diff] [blame] | 549 | // Simplify mul instructions with a constant RHS... |
Chris Lattner | a288196 | 2003-02-18 19:28:33 +0000 | [diff] [blame] | 550 | if (Constant *Op1 = dyn_cast<Constant>(I.getOperand(1))) { |
| 551 | if (ConstantInt *CI = dyn_cast<ConstantInt>(Op1)) { |
Chris Lattner | e92d2f4 | 2003-08-13 04:18:28 +0000 | [diff] [blame] | 552 | |
| 553 | // ((X << C1)*C2) == (X * (C2 << C1)) |
| 554 | if (ShiftInst *SI = dyn_cast<ShiftInst>(Op0)) |
| 555 | if (SI->getOpcode() == Instruction::Shl) |
| 556 | if (Constant *ShOp = dyn_cast<Constant>(SI->getOperand(1))) |
| 557 | return BinaryOperator::create(Instruction::Mul, SI->getOperand(0), |
| 558 | *CI << *ShOp); |
| 559 | |
Chris Lattner | 515c97c | 2003-09-11 22:24:54 +0000 | [diff] [blame] | 560 | if (CI->isNullValue()) |
| 561 | return ReplaceInstUsesWith(I, Op1); // X * 0 == 0 |
| 562 | if (CI->equalsInt(1)) // X * 1 == X |
| 563 | return ReplaceInstUsesWith(I, Op0); |
| 564 | if (CI->isAllOnesValue()) // X * -1 == 0 - X |
Chris Lattner | 0af1fab | 2003-06-25 17:09:20 +0000 | [diff] [blame] | 565 | return BinaryOperator::createNeg(Op0, I.getName()); |
Chris Lattner | 6c1ce21 | 2002-04-29 22:24:47 +0000 | [diff] [blame] | 566 | |
Chris Lattner | 515c97c | 2003-09-11 22:24:54 +0000 | [diff] [blame] | 567 | int64_t Val = (int64_t)cast<ConstantInt>(CI)->getRawValue(); |
Chris Lattner | a288196 | 2003-02-18 19:28:33 +0000 | [diff] [blame] | 568 | if (uint64_t C = Log2(Val)) // Replace X*(2^C) with X << C |
| 569 | return new ShiftInst(Instruction::Shl, Op0, |
| 570 | ConstantUInt::get(Type::UByteTy, C)); |
| 571 | } else { |
| 572 | ConstantFP *Op1F = cast<ConstantFP>(Op1); |
| 573 | if (Op1F->isNullValue()) |
| 574 | return ReplaceInstUsesWith(I, Op1); |
Chris Lattner | 6c1ce21 | 2002-04-29 22:24:47 +0000 | [diff] [blame] | 575 | |
Chris Lattner | a288196 | 2003-02-18 19:28:33 +0000 | [diff] [blame] | 576 | // "In IEEE floating point, x*1 is not equivalent to x for nans. However, |
| 577 | // ANSI says we can drop signals, so we can do this anyway." (from GCC) |
| 578 | if (Op1F->getValue() == 1.0) |
| 579 | return ReplaceInstUsesWith(I, Op0); // Eliminate 'mul double %X, 1.0' |
| 580 | } |
Chris Lattner | dd841ae | 2002-04-18 17:39:14 +0000 | [diff] [blame] | 581 | } |
| 582 | |
Chris Lattner | a4f445b | 2003-03-10 23:23:04 +0000 | [diff] [blame] | 583 | if (Value *Op0v = dyn_castNegVal(Op0)) // -X * -Y = X*Y |
| 584 | if (Value *Op1v = dyn_castNegVal(I.getOperand(1))) |
| 585 | return BinaryOperator::create(Instruction::Mul, Op0v, Op1v); |
| 586 | |
Chris Lattner | 7e70829 | 2002-06-25 16:13:24 +0000 | [diff] [blame] | 587 | return Changed ? &I : 0; |
Chris Lattner | dd841ae | 2002-04-18 17:39:14 +0000 | [diff] [blame] | 588 | } |
| 589 | |
Chris Lattner | 7e70829 | 2002-06-25 16:13:24 +0000 | [diff] [blame] | 590 | Instruction *InstCombiner::visitDiv(BinaryOperator &I) { |
Chris Lattner | 3f5b877 | 2002-05-06 16:14:14 +0000 | [diff] [blame] | 591 | // div X, 1 == X |
Chris Lattner | a288196 | 2003-02-18 19:28:33 +0000 | [diff] [blame] | 592 | if (ConstantInt *RHS = dyn_cast<ConstantInt>(I.getOperand(1))) { |
Chris Lattner | 233f7dc | 2002-08-12 21:17:25 +0000 | [diff] [blame] | 593 | if (RHS->equalsInt(1)) |
| 594 | return ReplaceInstUsesWith(I, I.getOperand(0)); |
Chris Lattner | a288196 | 2003-02-18 19:28:33 +0000 | [diff] [blame] | 595 | |
| 596 | // Check to see if this is an unsigned division with an exact power of 2, |
| 597 | // if so, convert to a right shift. |
| 598 | if (ConstantUInt *C = dyn_cast<ConstantUInt>(RHS)) |
| 599 | if (uint64_t Val = C->getValue()) // Don't break X / 0 |
| 600 | if (uint64_t C = Log2(Val)) |
| 601 | return new ShiftInst(Instruction::Shr, I.getOperand(0), |
| 602 | ConstantUInt::get(Type::UByteTy, C)); |
| 603 | } |
| 604 | |
| 605 | // 0 / X == 0, we don't need to preserve faults! |
| 606 | if (ConstantInt *LHS = dyn_cast<ConstantInt>(I.getOperand(0))) |
| 607 | if (LHS->equalsInt(0)) |
| 608 | return ReplaceInstUsesWith(I, Constant::getNullValue(I.getType())); |
| 609 | |
Chris Lattner | 3f5b877 | 2002-05-06 16:14:14 +0000 | [diff] [blame] | 610 | return 0; |
| 611 | } |
| 612 | |
| 613 | |
Chris Lattner | 7e70829 | 2002-06-25 16:13:24 +0000 | [diff] [blame] | 614 | Instruction *InstCombiner::visitRem(BinaryOperator &I) { |
Chris Lattner | a288196 | 2003-02-18 19:28:33 +0000 | [diff] [blame] | 615 | if (ConstantInt *RHS = dyn_cast<ConstantInt>(I.getOperand(1))) { |
| 616 | if (RHS->equalsInt(1)) // X % 1 == 0 |
| 617 | return ReplaceInstUsesWith(I, Constant::getNullValue(I.getType())); |
| 618 | |
| 619 | // Check to see if this is an unsigned remainder with an exact power of 2, |
| 620 | // if so, convert to a bitwise and. |
| 621 | if (ConstantUInt *C = dyn_cast<ConstantUInt>(RHS)) |
| 622 | if (uint64_t Val = C->getValue()) // Don't break X % 0 (divide by zero) |
| 623 | if (Log2(Val)) |
| 624 | return BinaryOperator::create(Instruction::And, I.getOperand(0), |
| 625 | ConstantUInt::get(I.getType(), Val-1)); |
| 626 | } |
| 627 | |
| 628 | // 0 % X == 0, we don't need to preserve faults! |
| 629 | if (ConstantInt *LHS = dyn_cast<ConstantInt>(I.getOperand(0))) |
| 630 | if (LHS->equalsInt(0)) |
Chris Lattner | 233f7dc | 2002-08-12 21:17:25 +0000 | [diff] [blame] | 631 | return ReplaceInstUsesWith(I, Constant::getNullValue(I.getType())); |
| 632 | |
Chris Lattner | 3f5b877 | 2002-05-06 16:14:14 +0000 | [diff] [blame] | 633 | return 0; |
| 634 | } |
| 635 | |
Chris Lattner | 8b17094 | 2002-08-09 23:47:40 +0000 | [diff] [blame] | 636 | // isMaxValueMinusOne - return true if this is Max-1 |
Chris Lattner | 233f7dc | 2002-08-12 21:17:25 +0000 | [diff] [blame] | 637 | static bool isMaxValueMinusOne(const ConstantInt *C) { |
Chris Lattner | 8b17094 | 2002-08-09 23:47:40 +0000 | [diff] [blame] | 638 | if (const ConstantUInt *CU = dyn_cast<ConstantUInt>(C)) { |
| 639 | // Calculate -1 casted to the right type... |
| 640 | unsigned TypeBits = C->getType()->getPrimitiveSize()*8; |
| 641 | uint64_t Val = ~0ULL; // All ones |
| 642 | Val >>= 64-TypeBits; // Shift out unwanted 1 bits... |
| 643 | return CU->getValue() == Val-1; |
| 644 | } |
| 645 | |
| 646 | const ConstantSInt *CS = cast<ConstantSInt>(C); |
| 647 | |
| 648 | // Calculate 0111111111..11111 |
| 649 | unsigned TypeBits = C->getType()->getPrimitiveSize()*8; |
| 650 | int64_t Val = INT64_MAX; // All ones |
| 651 | Val >>= 64-TypeBits; // Shift out unwanted 1 bits... |
| 652 | return CS->getValue() == Val-1; |
| 653 | } |
| 654 | |
| 655 | // isMinValuePlusOne - return true if this is Min+1 |
Chris Lattner | 233f7dc | 2002-08-12 21:17:25 +0000 | [diff] [blame] | 656 | static bool isMinValuePlusOne(const ConstantInt *C) { |
Chris Lattner | 8b17094 | 2002-08-09 23:47:40 +0000 | [diff] [blame] | 657 | if (const ConstantUInt *CU = dyn_cast<ConstantUInt>(C)) |
| 658 | return CU->getValue() == 1; |
| 659 | |
| 660 | const ConstantSInt *CS = cast<ConstantSInt>(C); |
| 661 | |
| 662 | // Calculate 1111111111000000000000 |
| 663 | unsigned TypeBits = C->getType()->getPrimitiveSize()*8; |
| 664 | int64_t Val = -1; // All ones |
| 665 | Val <<= TypeBits-1; // Shift over to the right spot |
| 666 | return CS->getValue() == Val+1; |
| 667 | } |
| 668 | |
Chris Lattner | aa9c1f1 | 2003-08-13 20:16:26 +0000 | [diff] [blame] | 669 | /// getSetCondCode - Encode a setcc opcode into a three bit mask. These bits |
| 670 | /// are carefully arranged to allow folding of expressions such as: |
| 671 | /// |
| 672 | /// (A < B) | (A > B) --> (A != B) |
| 673 | /// |
| 674 | /// Bit value '4' represents that the comparison is true if A > B, bit value '2' |
| 675 | /// represents that the comparison is true if A == B, and bit value '1' is true |
| 676 | /// if A < B. |
| 677 | /// |
| 678 | static unsigned getSetCondCode(const SetCondInst *SCI) { |
| 679 | switch (SCI->getOpcode()) { |
| 680 | // False -> 0 |
| 681 | case Instruction::SetGT: return 1; |
| 682 | case Instruction::SetEQ: return 2; |
| 683 | case Instruction::SetGE: return 3; |
| 684 | case Instruction::SetLT: return 4; |
| 685 | case Instruction::SetNE: return 5; |
| 686 | case Instruction::SetLE: return 6; |
| 687 | // True -> 7 |
| 688 | default: |
| 689 | assert(0 && "Invalid SetCC opcode!"); |
| 690 | return 0; |
| 691 | } |
| 692 | } |
| 693 | |
| 694 | /// getSetCCValue - This is the complement of getSetCondCode, which turns an |
| 695 | /// opcode and two operands into either a constant true or false, or a brand new |
| 696 | /// SetCC instruction. |
| 697 | static Value *getSetCCValue(unsigned Opcode, Value *LHS, Value *RHS) { |
| 698 | switch (Opcode) { |
| 699 | case 0: return ConstantBool::False; |
| 700 | case 1: return new SetCondInst(Instruction::SetGT, LHS, RHS); |
| 701 | case 2: return new SetCondInst(Instruction::SetEQ, LHS, RHS); |
| 702 | case 3: return new SetCondInst(Instruction::SetGE, LHS, RHS); |
| 703 | case 4: return new SetCondInst(Instruction::SetLT, LHS, RHS); |
| 704 | case 5: return new SetCondInst(Instruction::SetNE, LHS, RHS); |
| 705 | case 6: return new SetCondInst(Instruction::SetLE, LHS, RHS); |
| 706 | case 7: return ConstantBool::True; |
| 707 | default: assert(0 && "Illegal SetCCCode!"); return 0; |
| 708 | } |
| 709 | } |
| 710 | |
| 711 | // FoldSetCCLogical - Implements (setcc1 A, B) & (setcc2 A, B) --> (setcc3 A, B) |
| 712 | struct FoldSetCCLogical { |
| 713 | InstCombiner &IC; |
| 714 | Value *LHS, *RHS; |
| 715 | FoldSetCCLogical(InstCombiner &ic, SetCondInst *SCI) |
| 716 | : IC(ic), LHS(SCI->getOperand(0)), RHS(SCI->getOperand(1)) {} |
| 717 | bool shouldApply(Value *V) const { |
| 718 | if (SetCondInst *SCI = dyn_cast<SetCondInst>(V)) |
| 719 | return (SCI->getOperand(0) == LHS && SCI->getOperand(1) == RHS || |
| 720 | SCI->getOperand(0) == RHS && SCI->getOperand(1) == LHS); |
| 721 | return false; |
| 722 | } |
| 723 | Instruction *apply(BinaryOperator &Log) const { |
| 724 | SetCondInst *SCI = cast<SetCondInst>(Log.getOperand(0)); |
| 725 | if (SCI->getOperand(0) != LHS) { |
| 726 | assert(SCI->getOperand(1) == LHS); |
| 727 | SCI->swapOperands(); // Swap the LHS and RHS of the SetCC |
| 728 | } |
| 729 | |
| 730 | unsigned LHSCode = getSetCondCode(SCI); |
| 731 | unsigned RHSCode = getSetCondCode(cast<SetCondInst>(Log.getOperand(1))); |
| 732 | unsigned Code; |
| 733 | switch (Log.getOpcode()) { |
| 734 | case Instruction::And: Code = LHSCode & RHSCode; break; |
| 735 | case Instruction::Or: Code = LHSCode | RHSCode; break; |
| 736 | case Instruction::Xor: Code = LHSCode ^ RHSCode; break; |
Chris Lattner | 021c190 | 2003-09-22 20:33:34 +0000 | [diff] [blame] | 737 | default: assert(0 && "Illegal logical opcode!"); return 0; |
Chris Lattner | aa9c1f1 | 2003-08-13 20:16:26 +0000 | [diff] [blame] | 738 | } |
| 739 | |
| 740 | Value *RV = getSetCCValue(Code, LHS, RHS); |
| 741 | if (Instruction *I = dyn_cast<Instruction>(RV)) |
| 742 | return I; |
| 743 | // Otherwise, it's a constant boolean value... |
| 744 | return IC.ReplaceInstUsesWith(Log, RV); |
| 745 | } |
| 746 | }; |
| 747 | |
| 748 | |
Chris Lattner | bd7b5ff | 2003-09-19 17:17:26 +0000 | [diff] [blame] | 749 | // OptAndOp - This handles expressions of the form ((val OP C1) & C2). Where |
| 750 | // the Op parameter is 'OP', OpRHS is 'C1', and AndRHS is 'C2'. Op is |
| 751 | // guaranteed to be either a shift instruction or a binary operator. |
| 752 | Instruction *InstCombiner::OptAndOp(Instruction *Op, |
| 753 | ConstantIntegral *OpRHS, |
| 754 | ConstantIntegral *AndRHS, |
| 755 | BinaryOperator &TheAnd) { |
| 756 | Value *X = Op->getOperand(0); |
| 757 | switch (Op->getOpcode()) { |
| 758 | case Instruction::Xor: |
| 759 | if ((*AndRHS & *OpRHS)->isNullValue()) { |
| 760 | // (X ^ C1) & C2 --> (X & C2) iff (C1&C2) == 0 |
| 761 | return BinaryOperator::create(Instruction::And, X, AndRHS); |
Chris Lattner | fd05924 | 2003-10-15 16:48:29 +0000 | [diff] [blame] | 762 | } else if (Op->hasOneUse()) { |
Chris Lattner | bd7b5ff | 2003-09-19 17:17:26 +0000 | [diff] [blame] | 763 | // (X ^ C1) & C2 --> (X & C2) ^ (C1&C2) |
| 764 | std::string OpName = Op->getName(); Op->setName(""); |
| 765 | Instruction *And = BinaryOperator::create(Instruction::And, |
| 766 | X, AndRHS, OpName); |
| 767 | InsertNewInstBefore(And, TheAnd); |
| 768 | return BinaryOperator::create(Instruction::Xor, And, *AndRHS & *OpRHS); |
| 769 | } |
| 770 | break; |
| 771 | case Instruction::Or: |
| 772 | // (X | C1) & C2 --> X & C2 iff C1 & C1 == 0 |
| 773 | if ((*AndRHS & *OpRHS)->isNullValue()) |
| 774 | return BinaryOperator::create(Instruction::And, X, AndRHS); |
| 775 | else { |
| 776 | Constant *Together = *AndRHS & *OpRHS; |
| 777 | if (Together == AndRHS) // (X | C) & C --> C |
| 778 | return ReplaceInstUsesWith(TheAnd, AndRHS); |
| 779 | |
Chris Lattner | fd05924 | 2003-10-15 16:48:29 +0000 | [diff] [blame] | 780 | if (Op->hasOneUse() && Together != OpRHS) { |
Chris Lattner | bd7b5ff | 2003-09-19 17:17:26 +0000 | [diff] [blame] | 781 | // (X | C1) & C2 --> (X | (C1&C2)) & C2 |
| 782 | std::string Op0Name = Op->getName(); Op->setName(""); |
| 783 | Instruction *Or = BinaryOperator::create(Instruction::Or, X, |
| 784 | Together, Op0Name); |
| 785 | InsertNewInstBefore(Or, TheAnd); |
| 786 | return BinaryOperator::create(Instruction::And, Or, AndRHS); |
| 787 | } |
| 788 | } |
| 789 | break; |
| 790 | case Instruction::Add: |
Chris Lattner | fd05924 | 2003-10-15 16:48:29 +0000 | [diff] [blame] | 791 | if (Op->hasOneUse()) { |
Chris Lattner | bd7b5ff | 2003-09-19 17:17:26 +0000 | [diff] [blame] | 792 | // Adding a one to a single bit bit-field should be turned into an XOR |
| 793 | // of the bit. First thing to check is to see if this AND is with a |
| 794 | // single bit constant. |
| 795 | unsigned long long AndRHSV = cast<ConstantInt>(AndRHS)->getRawValue(); |
| 796 | |
| 797 | // Clear bits that are not part of the constant. |
| 798 | AndRHSV &= (1ULL << AndRHS->getType()->getPrimitiveSize()*8)-1; |
| 799 | |
| 800 | // If there is only one bit set... |
| 801 | if ((AndRHSV & (AndRHSV-1)) == 0) { |
| 802 | // Ok, at this point, we know that we are masking the result of the |
| 803 | // ADD down to exactly one bit. If the constant we are adding has |
| 804 | // no bits set below this bit, then we can eliminate the ADD. |
| 805 | unsigned long long AddRHS = cast<ConstantInt>(OpRHS)->getRawValue(); |
| 806 | |
| 807 | // Check to see if any bits below the one bit set in AndRHSV are set. |
| 808 | if ((AddRHS & (AndRHSV-1)) == 0) { |
| 809 | // If not, the only thing that can effect the output of the AND is |
| 810 | // the bit specified by AndRHSV. If that bit is set, the effect of |
| 811 | // the XOR is to toggle the bit. If it is clear, then the ADD has |
| 812 | // no effect. |
| 813 | if ((AddRHS & AndRHSV) == 0) { // Bit is not set, noop |
| 814 | TheAnd.setOperand(0, X); |
| 815 | return &TheAnd; |
| 816 | } else { |
| 817 | std::string Name = Op->getName(); Op->setName(""); |
| 818 | // Pull the XOR out of the AND. |
| 819 | Instruction *NewAnd = |
| 820 | BinaryOperator::create(Instruction::And, X, AndRHS, Name); |
| 821 | InsertNewInstBefore(NewAnd, TheAnd); |
| 822 | return BinaryOperator::create(Instruction::Xor, NewAnd, AndRHS); |
| 823 | } |
| 824 | } |
| 825 | } |
| 826 | } |
| 827 | break; |
Chris Lattner | 62a355c | 2003-09-19 19:05:02 +0000 | [diff] [blame] | 828 | |
| 829 | case Instruction::Shl: { |
| 830 | // We know that the AND will not produce any of the bits shifted in, so if |
| 831 | // the anded constant includes them, clear them now! |
| 832 | // |
| 833 | Constant *AllOne = ConstantIntegral::getAllOnesValue(AndRHS->getType()); |
| 834 | Constant *CI = *AndRHS & *(*AllOne << *OpRHS); |
| 835 | if (CI != AndRHS) { |
| 836 | TheAnd.setOperand(1, CI); |
| 837 | return &TheAnd; |
| 838 | } |
| 839 | break; |
| 840 | } |
| 841 | case Instruction::Shr: |
| 842 | // We know that the AND will not produce any of the bits shifted in, so if |
| 843 | // the anded constant includes them, clear them now! This only applies to |
| 844 | // unsigned shifts, because a signed shr may bring in set bits! |
| 845 | // |
| 846 | if (AndRHS->getType()->isUnsigned()) { |
| 847 | Constant *AllOne = ConstantIntegral::getAllOnesValue(AndRHS->getType()); |
| 848 | Constant *CI = *AndRHS & *(*AllOne >> *OpRHS); |
| 849 | if (CI != AndRHS) { |
| 850 | TheAnd.setOperand(1, CI); |
| 851 | return &TheAnd; |
| 852 | } |
| 853 | } |
| 854 | break; |
Chris Lattner | bd7b5ff | 2003-09-19 17:17:26 +0000 | [diff] [blame] | 855 | } |
| 856 | return 0; |
| 857 | } |
| 858 | |
Chris Lattner | 8b17094 | 2002-08-09 23:47:40 +0000 | [diff] [blame] | 859 | |
Chris Lattner | 7e70829 | 2002-06-25 16:13:24 +0000 | [diff] [blame] | 860 | Instruction *InstCombiner::visitAnd(BinaryOperator &I) { |
Chris Lattner | 4f98c56 | 2003-03-10 21:43:22 +0000 | [diff] [blame] | 861 | bool Changed = SimplifyCommutative(I); |
Chris Lattner | 7e70829 | 2002-06-25 16:13:24 +0000 | [diff] [blame] | 862 | Value *Op0 = I.getOperand(0), *Op1 = I.getOperand(1); |
Chris Lattner | 3f5b877 | 2002-05-06 16:14:14 +0000 | [diff] [blame] | 863 | |
| 864 | // and X, X = X and X, 0 == 0 |
Chris Lattner | 233f7dc | 2002-08-12 21:17:25 +0000 | [diff] [blame] | 865 | if (Op0 == Op1 || Op1 == Constant::getNullValue(I.getType())) |
| 866 | return ReplaceInstUsesWith(I, Op1); |
Chris Lattner | 3f5b877 | 2002-05-06 16:14:14 +0000 | [diff] [blame] | 867 | |
| 868 | // and X, -1 == X |
Chris Lattner | c6a8aff | 2003-07-23 17:57:01 +0000 | [diff] [blame] | 869 | if (ConstantIntegral *RHS = dyn_cast<ConstantIntegral>(Op1)) { |
Chris Lattner | 233f7dc | 2002-08-12 21:17:25 +0000 | [diff] [blame] | 870 | if (RHS->isAllOnesValue()) |
| 871 | return ReplaceInstUsesWith(I, Op0); |
Chris Lattner | 3f5b877 | 2002-05-06 16:14:14 +0000 | [diff] [blame] | 872 | |
Chris Lattner | bd7b5ff | 2003-09-19 17:17:26 +0000 | [diff] [blame] | 873 | // Optimize a variety of ((val OP C1) & C2) combinations... |
| 874 | if (isa<BinaryOperator>(Op0) || isa<ShiftInst>(Op0)) { |
| 875 | Instruction *Op0I = cast<Instruction>(Op0); |
Chris Lattner | 06782f8 | 2003-07-23 19:36:21 +0000 | [diff] [blame] | 876 | Value *X = Op0I->getOperand(0); |
Chris Lattner | 5840326 | 2003-07-23 19:25:52 +0000 | [diff] [blame] | 877 | if (ConstantInt *Op0CI = dyn_cast<ConstantInt>(Op0I->getOperand(1))) |
Chris Lattner | bd7b5ff | 2003-09-19 17:17:26 +0000 | [diff] [blame] | 878 | if (Instruction *Res = OptAndOp(Op0I, Op0CI, RHS, I)) |
| 879 | return Res; |
Chris Lattner | 06782f8 | 2003-07-23 19:36:21 +0000 | [diff] [blame] | 880 | } |
Chris Lattner | c6a8aff | 2003-07-23 17:57:01 +0000 | [diff] [blame] | 881 | } |
| 882 | |
Chris Lattner | 8d96964 | 2003-03-10 23:06:50 +0000 | [diff] [blame] | 883 | Value *Op0NotVal = dyn_castNotVal(Op0); |
| 884 | Value *Op1NotVal = dyn_castNotVal(Op1); |
Chris Lattner | a288196 | 2003-02-18 19:28:33 +0000 | [diff] [blame] | 885 | |
| 886 | // (~A & ~B) == (~(A | B)) - Demorgan's Law |
Chris Lattner | 8d96964 | 2003-03-10 23:06:50 +0000 | [diff] [blame] | 887 | if (Op0NotVal && Op1NotVal && isOnlyUse(Op0) && isOnlyUse(Op1)) { |
Chris Lattner | a288196 | 2003-02-18 19:28:33 +0000 | [diff] [blame] | 888 | Instruction *Or = BinaryOperator::create(Instruction::Or, Op0NotVal, |
Chris Lattner | c6a8aff | 2003-07-23 17:57:01 +0000 | [diff] [blame] | 889 | Op1NotVal,I.getName()+".demorgan"); |
| 890 | InsertNewInstBefore(Or, I); |
Chris Lattner | a288196 | 2003-02-18 19:28:33 +0000 | [diff] [blame] | 891 | return BinaryOperator::createNot(Or); |
| 892 | } |
| 893 | |
| 894 | if (Op0NotVal == Op1 || Op1NotVal == Op0) // A & ~A == ~A & A == 0 |
| 895 | return ReplaceInstUsesWith(I, Constant::getNullValue(I.getType())); |
Chris Lattner | e6f9a91 | 2002-08-23 18:32:43 +0000 | [diff] [blame] | 896 | |
Chris Lattner | aa9c1f1 | 2003-08-13 20:16:26 +0000 | [diff] [blame] | 897 | // (setcc1 A, B) & (setcc2 A, B) --> (setcc3 A, B) |
| 898 | if (SetCondInst *RHS = dyn_cast<SetCondInst>(I.getOperand(1))) |
| 899 | if (Instruction *R = AssociativeOpt(I, FoldSetCCLogical(*this, RHS))) |
| 900 | return R; |
| 901 | |
Chris Lattner | 7e70829 | 2002-06-25 16:13:24 +0000 | [diff] [blame] | 902 | return Changed ? &I : 0; |
Chris Lattner | 3f5b877 | 2002-05-06 16:14:14 +0000 | [diff] [blame] | 903 | } |
| 904 | |
| 905 | |
| 906 | |
Chris Lattner | 7e70829 | 2002-06-25 16:13:24 +0000 | [diff] [blame] | 907 | Instruction *InstCombiner::visitOr(BinaryOperator &I) { |
Chris Lattner | 4f98c56 | 2003-03-10 21:43:22 +0000 | [diff] [blame] | 908 | bool Changed = SimplifyCommutative(I); |
Chris Lattner | 7e70829 | 2002-06-25 16:13:24 +0000 | [diff] [blame] | 909 | Value *Op0 = I.getOperand(0), *Op1 = I.getOperand(1); |
Chris Lattner | 3f5b877 | 2002-05-06 16:14:14 +0000 | [diff] [blame] | 910 | |
| 911 | // or X, X = X or X, 0 == X |
Chris Lattner | 233f7dc | 2002-08-12 21:17:25 +0000 | [diff] [blame] | 912 | if (Op0 == Op1 || Op1 == Constant::getNullValue(I.getType())) |
| 913 | return ReplaceInstUsesWith(I, Op0); |
Chris Lattner | 3f5b877 | 2002-05-06 16:14:14 +0000 | [diff] [blame] | 914 | |
| 915 | // or X, -1 == -1 |
Chris Lattner | ad44ebf | 2003-07-23 18:29:44 +0000 | [diff] [blame] | 916 | if (ConstantIntegral *RHS = dyn_cast<ConstantIntegral>(Op1)) { |
Chris Lattner | 233f7dc | 2002-08-12 21:17:25 +0000 | [diff] [blame] | 917 | if (RHS->isAllOnesValue()) |
| 918 | return ReplaceInstUsesWith(I, Op1); |
Chris Lattner | 3f5b877 | 2002-05-06 16:14:14 +0000 | [diff] [blame] | 919 | |
Chris Lattner | ad44ebf | 2003-07-23 18:29:44 +0000 | [diff] [blame] | 920 | if (Instruction *Op0I = dyn_cast<Instruction>(Op0)) { |
| 921 | // (X & C1) | C2 --> (X | C2) & (C1|C2) |
| 922 | if (Op0I->getOpcode() == Instruction::And && isOnlyUse(Op0)) |
| 923 | if (ConstantInt *Op0CI = dyn_cast<ConstantInt>(Op0I->getOperand(1))) { |
| 924 | std::string Op0Name = Op0I->getName(); Op0I->setName(""); |
| 925 | Instruction *Or = BinaryOperator::create(Instruction::Or, |
| 926 | Op0I->getOperand(0), RHS, |
| 927 | Op0Name); |
| 928 | InsertNewInstBefore(Or, I); |
| 929 | return BinaryOperator::create(Instruction::And, Or, *RHS | *Op0CI); |
| 930 | } |
| 931 | |
| 932 | // (X ^ C1) | C2 --> (X | C2) ^ (C1&~C2) |
| 933 | if (Op0I->getOpcode() == Instruction::Xor && isOnlyUse(Op0)) |
| 934 | if (ConstantInt *Op0CI = dyn_cast<ConstantInt>(Op0I->getOperand(1))) { |
| 935 | std::string Op0Name = Op0I->getName(); Op0I->setName(""); |
| 936 | Instruction *Or = BinaryOperator::create(Instruction::Or, |
| 937 | Op0I->getOperand(0), RHS, |
| 938 | Op0Name); |
| 939 | InsertNewInstBefore(Or, I); |
| 940 | return BinaryOperator::create(Instruction::Xor, Or, *Op0CI & *~*RHS); |
| 941 | } |
| 942 | } |
| 943 | } |
| 944 | |
Chris Lattner | 67ca768 | 2003-08-12 19:11:07 +0000 | [diff] [blame] | 945 | // (A & C1)|(A & C2) == A & (C1|C2) |
Chris Lattner | e132d95 | 2003-08-12 19:17:27 +0000 | [diff] [blame] | 946 | if (Instruction *LHS = dyn_cast<BinaryOperator>(Op0)) |
| 947 | if (Instruction *RHS = dyn_cast<BinaryOperator>(Op1)) |
| 948 | if (LHS->getOperand(0) == RHS->getOperand(0)) |
| 949 | if (Constant *C0 = dyn_castMaskingAnd(LHS)) |
| 950 | if (Constant *C1 = dyn_castMaskingAnd(RHS)) |
| 951 | return BinaryOperator::create(Instruction::And, LHS->getOperand(0), |
Chris Lattner | 67ca768 | 2003-08-12 19:11:07 +0000 | [diff] [blame] | 952 | *C0 | *C1); |
| 953 | |
Chris Lattner | a27231a | 2003-03-10 23:13:59 +0000 | [diff] [blame] | 954 | Value *Op0NotVal = dyn_castNotVal(Op0); |
| 955 | Value *Op1NotVal = dyn_castNotVal(Op1); |
Chris Lattner | a288196 | 2003-02-18 19:28:33 +0000 | [diff] [blame] | 956 | |
Chris Lattner | a27231a | 2003-03-10 23:13:59 +0000 | [diff] [blame] | 957 | if (Op1 == Op0NotVal) // ~A | A == -1 |
| 958 | return ReplaceInstUsesWith(I, |
| 959 | ConstantIntegral::getAllOnesValue(I.getType())); |
| 960 | |
| 961 | if (Op0 == Op1NotVal) // A | ~A == -1 |
| 962 | return ReplaceInstUsesWith(I, |
| 963 | ConstantIntegral::getAllOnesValue(I.getType())); |
| 964 | |
| 965 | // (~A | ~B) == (~(A & B)) - Demorgan's Law |
| 966 | if (Op0NotVal && Op1NotVal && isOnlyUse(Op0) && isOnlyUse(Op1)) { |
| 967 | Instruction *And = BinaryOperator::create(Instruction::And, Op0NotVal, |
| 968 | Op1NotVal,I.getName()+".demorgan", |
| 969 | &I); |
| 970 | WorkList.push_back(And); |
| 971 | return BinaryOperator::createNot(And); |
| 972 | } |
Chris Lattner | a288196 | 2003-02-18 19:28:33 +0000 | [diff] [blame] | 973 | |
Chris Lattner | aa9c1f1 | 2003-08-13 20:16:26 +0000 | [diff] [blame] | 974 | // (setcc1 A, B) | (setcc2 A, B) --> (setcc3 A, B) |
| 975 | if (SetCondInst *RHS = dyn_cast<SetCondInst>(I.getOperand(1))) |
| 976 | if (Instruction *R = AssociativeOpt(I, FoldSetCCLogical(*this, RHS))) |
| 977 | return R; |
| 978 | |
Chris Lattner | 7e70829 | 2002-06-25 16:13:24 +0000 | [diff] [blame] | 979 | return Changed ? &I : 0; |
Chris Lattner | 3f5b877 | 2002-05-06 16:14:14 +0000 | [diff] [blame] | 980 | } |
| 981 | |
| 982 | |
| 983 | |
Chris Lattner | 7e70829 | 2002-06-25 16:13:24 +0000 | [diff] [blame] | 984 | Instruction *InstCombiner::visitXor(BinaryOperator &I) { |
Chris Lattner | 4f98c56 | 2003-03-10 21:43:22 +0000 | [diff] [blame] | 985 | bool Changed = SimplifyCommutative(I); |
Chris Lattner | 7e70829 | 2002-06-25 16:13:24 +0000 | [diff] [blame] | 986 | Value *Op0 = I.getOperand(0), *Op1 = I.getOperand(1); |
Chris Lattner | 3f5b877 | 2002-05-06 16:14:14 +0000 | [diff] [blame] | 987 | |
| 988 | // xor X, X = 0 |
Chris Lattner | 233f7dc | 2002-08-12 21:17:25 +0000 | [diff] [blame] | 989 | if (Op0 == Op1) |
| 990 | return ReplaceInstUsesWith(I, Constant::getNullValue(I.getType())); |
Chris Lattner | 3f5b877 | 2002-05-06 16:14:14 +0000 | [diff] [blame] | 991 | |
Chris Lattner | eca0c5c | 2003-07-23 21:37:07 +0000 | [diff] [blame] | 992 | if (ConstantIntegral *RHS = dyn_cast<ConstantIntegral>(Op1)) { |
Chris Lattner | 8b17094 | 2002-08-09 23:47:40 +0000 | [diff] [blame] | 993 | // xor X, 0 == X |
Chris Lattner | eca0c5c | 2003-07-23 21:37:07 +0000 | [diff] [blame] | 994 | if (RHS->isNullValue()) |
Chris Lattner | 233f7dc | 2002-08-12 21:17:25 +0000 | [diff] [blame] | 995 | return ReplaceInstUsesWith(I, Op0); |
Chris Lattner | 8b17094 | 2002-08-09 23:47:40 +0000 | [diff] [blame] | 996 | |
Chris Lattner | eca0c5c | 2003-07-23 21:37:07 +0000 | [diff] [blame] | 997 | if (BinaryOperator *Op0I = dyn_cast<BinaryOperator>(Op0)) { |
Chris Lattner | 05bd1b2 | 2002-08-20 18:24:26 +0000 | [diff] [blame] | 998 | // xor (setcc A, B), true = not (setcc A, B) = setncc A, B |
Chris Lattner | eca0c5c | 2003-07-23 21:37:07 +0000 | [diff] [blame] | 999 | if (SetCondInst *SCI = dyn_cast<SetCondInst>(Op0I)) |
Chris Lattner | fd05924 | 2003-10-15 16:48:29 +0000 | [diff] [blame] | 1000 | if (RHS == ConstantBool::True && SCI->hasOneUse()) |
Chris Lattner | 05bd1b2 | 2002-08-20 18:24:26 +0000 | [diff] [blame] | 1001 | return new SetCondInst(SCI->getInverseCondition(), |
| 1002 | SCI->getOperand(0), SCI->getOperand(1)); |
Chris Lattner | eca0c5c | 2003-07-23 21:37:07 +0000 | [diff] [blame] | 1003 | |
| 1004 | if (ConstantInt *Op0CI = dyn_cast<ConstantInt>(Op0I->getOperand(1))) |
| 1005 | if (Op0I->getOpcode() == Instruction::And) { |
| 1006 | // (X & C1) ^ C2 --> (X & C1) | C2 iff (C1&C2) == 0 |
| 1007 | if ((*RHS & *Op0CI)->isNullValue()) |
| 1008 | return BinaryOperator::create(Instruction::Or, Op0, RHS); |
| 1009 | } else if (Op0I->getOpcode() == Instruction::Or) { |
| 1010 | // (X | C1) ^ C2 --> (X | C1) & ~C2 iff (C1&C2) == C2 |
| 1011 | if ((*RHS & *Op0CI) == RHS) |
| 1012 | return BinaryOperator::create(Instruction::And, Op0, ~*RHS); |
| 1013 | } |
Chris Lattner | 05bd1b2 | 2002-08-20 18:24:26 +0000 | [diff] [blame] | 1014 | } |
Chris Lattner | 3f5b877 | 2002-05-06 16:14:14 +0000 | [diff] [blame] | 1015 | } |
| 1016 | |
Chris Lattner | 8d96964 | 2003-03-10 23:06:50 +0000 | [diff] [blame] | 1017 | if (Value *X = dyn_castNotVal(Op0)) // ~A ^ A == -1 |
Chris Lattner | a288196 | 2003-02-18 19:28:33 +0000 | [diff] [blame] | 1018 | if (X == Op1) |
| 1019 | return ReplaceInstUsesWith(I, |
| 1020 | ConstantIntegral::getAllOnesValue(I.getType())); |
| 1021 | |
Chris Lattner | 8d96964 | 2003-03-10 23:06:50 +0000 | [diff] [blame] | 1022 | if (Value *X = dyn_castNotVal(Op1)) // A ^ ~A == -1 |
Chris Lattner | a288196 | 2003-02-18 19:28:33 +0000 | [diff] [blame] | 1023 | if (X == Op0) |
| 1024 | return ReplaceInstUsesWith(I, |
| 1025 | ConstantIntegral::getAllOnesValue(I.getType())); |
| 1026 | |
Chris Lattner | cb40a37 | 2003-03-10 18:24:17 +0000 | [diff] [blame] | 1027 | if (Instruction *Op1I = dyn_cast<Instruction>(Op1)) |
| 1028 | if (Op1I->getOpcode() == Instruction::Or) |
| 1029 | if (Op1I->getOperand(0) == Op0) { // B^(B|A) == (A|B)^B |
| 1030 | cast<BinaryOperator>(Op1I)->swapOperands(); |
| 1031 | I.swapOperands(); |
| 1032 | std::swap(Op0, Op1); |
| 1033 | } else if (Op1I->getOperand(1) == Op0) { // B^(A|B) == (A|B)^B |
| 1034 | I.swapOperands(); |
| 1035 | std::swap(Op0, Op1); |
| 1036 | } |
| 1037 | |
| 1038 | if (Instruction *Op0I = dyn_cast<Instruction>(Op0)) |
Chris Lattner | fd05924 | 2003-10-15 16:48:29 +0000 | [diff] [blame] | 1039 | if (Op0I->getOpcode() == Instruction::Or && Op0I->hasOneUse()) { |
Chris Lattner | cb40a37 | 2003-03-10 18:24:17 +0000 | [diff] [blame] | 1040 | if (Op0I->getOperand(0) == Op1) // (B|A)^B == (A|B)^B |
| 1041 | cast<BinaryOperator>(Op0I)->swapOperands(); |
Chris Lattner | 4f98c56 | 2003-03-10 21:43:22 +0000 | [diff] [blame] | 1042 | if (Op0I->getOperand(1) == Op1) { // (A|B)^B == A & ~B |
Chris Lattner | cb40a37 | 2003-03-10 18:24:17 +0000 | [diff] [blame] | 1043 | Value *NotB = BinaryOperator::createNot(Op1, Op1->getName()+".not", &I); |
| 1044 | WorkList.push_back(cast<Instruction>(NotB)); |
Chris Lattner | 4f98c56 | 2003-03-10 21:43:22 +0000 | [diff] [blame] | 1045 | return BinaryOperator::create(Instruction::And, Op0I->getOperand(0), |
| 1046 | NotB); |
Chris Lattner | cb40a37 | 2003-03-10 18:24:17 +0000 | [diff] [blame] | 1047 | } |
| 1048 | } |
| 1049 | |
Chris Lattner | c8802d2 | 2003-03-11 00:12:48 +0000 | [diff] [blame] | 1050 | // (A & C1)^(B & C2) -> (A & C1)|(B & C2) iff C1^C2 == 0 |
| 1051 | if (Constant *C1 = dyn_castMaskingAnd(Op0)) |
| 1052 | if (Constant *C2 = dyn_castMaskingAnd(Op1)) |
Chris Lattner | 2a9c847 | 2003-05-27 16:40:51 +0000 | [diff] [blame] | 1053 | if (ConstantExpr::get(Instruction::And, C1, C2)->isNullValue()) |
Chris Lattner | c8802d2 | 2003-03-11 00:12:48 +0000 | [diff] [blame] | 1054 | return BinaryOperator::create(Instruction::Or, Op0, Op1); |
| 1055 | |
Chris Lattner | aa9c1f1 | 2003-08-13 20:16:26 +0000 | [diff] [blame] | 1056 | // (setcc1 A, B) ^ (setcc2 A, B) --> (setcc3 A, B) |
| 1057 | if (SetCondInst *RHS = dyn_cast<SetCondInst>(I.getOperand(1))) |
| 1058 | if (Instruction *R = AssociativeOpt(I, FoldSetCCLogical(*this, RHS))) |
| 1059 | return R; |
| 1060 | |
Chris Lattner | 7e70829 | 2002-06-25 16:13:24 +0000 | [diff] [blame] | 1061 | return Changed ? &I : 0; |
Chris Lattner | 3f5b877 | 2002-05-06 16:14:14 +0000 | [diff] [blame] | 1062 | } |
| 1063 | |
Chris Lattner | 8b17094 | 2002-08-09 23:47:40 +0000 | [diff] [blame] | 1064 | // AddOne, SubOne - Add or subtract a constant one from an integer constant... |
| 1065 | static Constant *AddOne(ConstantInt *C) { |
Chris Lattner | 2a9c847 | 2003-05-27 16:40:51 +0000 | [diff] [blame] | 1066 | Constant *Result = ConstantExpr::get(Instruction::Add, C, |
| 1067 | ConstantInt::get(C->getType(), 1)); |
Chris Lattner | 8b17094 | 2002-08-09 23:47:40 +0000 | [diff] [blame] | 1068 | assert(Result && "Constant folding integer addition failed!"); |
| 1069 | return Result; |
| 1070 | } |
| 1071 | static Constant *SubOne(ConstantInt *C) { |
Chris Lattner | 2a9c847 | 2003-05-27 16:40:51 +0000 | [diff] [blame] | 1072 | Constant *Result = ConstantExpr::get(Instruction::Sub, C, |
| 1073 | ConstantInt::get(C->getType(), 1)); |
Chris Lattner | 8b17094 | 2002-08-09 23:47:40 +0000 | [diff] [blame] | 1074 | assert(Result && "Constant folding integer addition failed!"); |
| 1075 | return Result; |
| 1076 | } |
| 1077 | |
Chris Lattner | 53a5b57 | 2002-05-09 20:11:54 +0000 | [diff] [blame] | 1078 | // isTrueWhenEqual - Return true if the specified setcondinst instruction is |
| 1079 | // true when both operands are equal... |
| 1080 | // |
Chris Lattner | 7e70829 | 2002-06-25 16:13:24 +0000 | [diff] [blame] | 1081 | static bool isTrueWhenEqual(Instruction &I) { |
| 1082 | return I.getOpcode() == Instruction::SetEQ || |
| 1083 | I.getOpcode() == Instruction::SetGE || |
| 1084 | I.getOpcode() == Instruction::SetLE; |
Chris Lattner | 53a5b57 | 2002-05-09 20:11:54 +0000 | [diff] [blame] | 1085 | } |
| 1086 | |
Chris Lattner | 7e70829 | 2002-06-25 16:13:24 +0000 | [diff] [blame] | 1087 | Instruction *InstCombiner::visitSetCondInst(BinaryOperator &I) { |
Chris Lattner | 4f98c56 | 2003-03-10 21:43:22 +0000 | [diff] [blame] | 1088 | bool Changed = SimplifyCommutative(I); |
Chris Lattner | 8b17094 | 2002-08-09 23:47:40 +0000 | [diff] [blame] | 1089 | Value *Op0 = I.getOperand(0), *Op1 = I.getOperand(1); |
| 1090 | const Type *Ty = Op0->getType(); |
Chris Lattner | 3f5b877 | 2002-05-06 16:14:14 +0000 | [diff] [blame] | 1091 | |
| 1092 | // setcc X, X |
Chris Lattner | 8b17094 | 2002-08-09 23:47:40 +0000 | [diff] [blame] | 1093 | if (Op0 == Op1) |
| 1094 | return ReplaceInstUsesWith(I, ConstantBool::get(isTrueWhenEqual(I))); |
Chris Lattner | 53a5b57 | 2002-05-09 20:11:54 +0000 | [diff] [blame] | 1095 | |
Chris Lattner | 3ccd17e | 2003-08-13 05:38:46 +0000 | [diff] [blame] | 1096 | // setcc <global/alloca*>, 0 - Global/Stack value addresses are never null! |
| 1097 | if (isa<ConstantPointerNull>(Op1) && |
| 1098 | (isa<GlobalValue>(Op0) || isa<AllocaInst>(Op0))) |
Chris Lattner | 8b17094 | 2002-08-09 23:47:40 +0000 | [diff] [blame] | 1099 | return ReplaceInstUsesWith(I, ConstantBool::get(!isTrueWhenEqual(I))); |
| 1100 | |
Chris Lattner | 3ccd17e | 2003-08-13 05:38:46 +0000 | [diff] [blame] | 1101 | |
Chris Lattner | 8b17094 | 2002-08-09 23:47:40 +0000 | [diff] [blame] | 1102 | // setcc's with boolean values can always be turned into bitwise operations |
| 1103 | if (Ty == Type::BoolTy) { |
| 1104 | // If this is <, >, or !=, we can change this into a simple xor instruction |
| 1105 | if (!isTrueWhenEqual(I)) |
| 1106 | return BinaryOperator::create(Instruction::Xor, Op0, Op1, I.getName()); |
| 1107 | |
| 1108 | // Otherwise we need to make a temporary intermediate instruction and insert |
| 1109 | // it into the instruction stream. This is what we are after: |
| 1110 | // |
| 1111 | // seteq bool %A, %B -> ~(A^B) |
| 1112 | // setle bool %A, %B -> ~A | B |
| 1113 | // setge bool %A, %B -> A | ~B |
| 1114 | // |
| 1115 | if (I.getOpcode() == Instruction::SetEQ) { // seteq case |
| 1116 | Instruction *Xor = BinaryOperator::create(Instruction::Xor, Op0, Op1, |
| 1117 | I.getName()+"tmp"); |
| 1118 | InsertNewInstBefore(Xor, I); |
Chris Lattner | af2930e | 2002-08-14 17:51:49 +0000 | [diff] [blame] | 1119 | return BinaryOperator::createNot(Xor, I.getName()); |
Chris Lattner | 8b17094 | 2002-08-09 23:47:40 +0000 | [diff] [blame] | 1120 | } |
| 1121 | |
| 1122 | // Handle the setXe cases... |
| 1123 | assert(I.getOpcode() == Instruction::SetGE || |
| 1124 | I.getOpcode() == Instruction::SetLE); |
| 1125 | |
| 1126 | if (I.getOpcode() == Instruction::SetGE) |
| 1127 | std::swap(Op0, Op1); // Change setge -> setle |
| 1128 | |
| 1129 | // Now we just have the SetLE case. |
Chris Lattner | af2930e | 2002-08-14 17:51:49 +0000 | [diff] [blame] | 1130 | Instruction *Not = BinaryOperator::createNot(Op0, I.getName()+"tmp"); |
Chris Lattner | 8b17094 | 2002-08-09 23:47:40 +0000 | [diff] [blame] | 1131 | InsertNewInstBefore(Not, I); |
| 1132 | return BinaryOperator::create(Instruction::Or, Not, Op1, I.getName()); |
| 1133 | } |
| 1134 | |
| 1135 | // Check to see if we are doing one of many comparisons against constant |
| 1136 | // integers at the end of their ranges... |
| 1137 | // |
| 1138 | if (ConstantInt *CI = dyn_cast<ConstantInt>(Op1)) { |
Chris Lattner | bc5d414 | 2003-07-23 17:02:11 +0000 | [diff] [blame] | 1139 | // Simplify seteq and setne instructions... |
| 1140 | if (I.getOpcode() == Instruction::SetEQ || |
| 1141 | I.getOpcode() == Instruction::SetNE) { |
| 1142 | bool isSetNE = I.getOpcode() == Instruction::SetNE; |
| 1143 | |
Chris Lattner | 00b1a7e | 2003-07-23 17:26:36 +0000 | [diff] [blame] | 1144 | // If the first operand is (and|or|xor) with a constant, and the second |
Chris Lattner | bc5d414 | 2003-07-23 17:02:11 +0000 | [diff] [blame] | 1145 | // operand is a constant, simplify a bit. |
Chris Lattner | 934754b | 2003-08-13 05:33:12 +0000 | [diff] [blame] | 1146 | if (BinaryOperator *BO = dyn_cast<BinaryOperator>(Op0)) { |
| 1147 | switch (BO->getOpcode()) { |
| 1148 | case Instruction::Add: |
| 1149 | if (CI->isNullValue()) { |
| 1150 | // Replace ((add A, B) != 0) with (A != -B) if A or B is |
| 1151 | // efficiently invertible, or if the add has just this one use. |
| 1152 | Value *BOp0 = BO->getOperand(0), *BOp1 = BO->getOperand(1); |
| 1153 | if (Value *NegVal = dyn_castNegVal(BOp1)) |
| 1154 | return new SetCondInst(I.getOpcode(), BOp0, NegVal); |
| 1155 | else if (Value *NegVal = dyn_castNegVal(BOp0)) |
| 1156 | return new SetCondInst(I.getOpcode(), NegVal, BOp1); |
Chris Lattner | fd05924 | 2003-10-15 16:48:29 +0000 | [diff] [blame] | 1157 | else if (BO->hasOneUse()) { |
Chris Lattner | 934754b | 2003-08-13 05:33:12 +0000 | [diff] [blame] | 1158 | Instruction *Neg = BinaryOperator::createNeg(BOp1, BO->getName()); |
| 1159 | BO->setName(""); |
| 1160 | InsertNewInstBefore(Neg, I); |
| 1161 | return new SetCondInst(I.getOpcode(), BOp0, Neg); |
| 1162 | } |
| 1163 | } |
| 1164 | break; |
| 1165 | case Instruction::Xor: |
| 1166 | // For the xor case, we can xor two constants together, eliminating |
| 1167 | // the explicit xor. |
| 1168 | if (Constant *BOC = dyn_cast<Constant>(BO->getOperand(1))) |
| 1169 | return BinaryOperator::create(I.getOpcode(), BO->getOperand(0), |
| 1170 | *CI ^ *BOC); |
| 1171 | |
| 1172 | // FALLTHROUGH |
| 1173 | case Instruction::Sub: |
| 1174 | // Replace (([sub|xor] A, B) != 0) with (A != B) |
| 1175 | if (CI->isNullValue()) |
| 1176 | return new SetCondInst(I.getOpcode(), BO->getOperand(0), |
| 1177 | BO->getOperand(1)); |
| 1178 | break; |
| 1179 | |
| 1180 | case Instruction::Or: |
| 1181 | // If bits are being or'd in that are not present in the constant we |
| 1182 | // are comparing against, then the comparison could never succeed! |
| 1183 | if (Constant *BOC = dyn_cast<Constant>(BO->getOperand(1))) |
Chris Lattner | bc5d414 | 2003-07-23 17:02:11 +0000 | [diff] [blame] | 1184 | if (!(*BOC & *~*CI)->isNullValue()) |
| 1185 | return ReplaceInstUsesWith(I, ConstantBool::get(isSetNE)); |
Chris Lattner | 934754b | 2003-08-13 05:33:12 +0000 | [diff] [blame] | 1186 | break; |
| 1187 | |
| 1188 | case Instruction::And: |
| 1189 | if (ConstantInt *BOC = dyn_cast<ConstantInt>(BO->getOperand(1))) { |
Chris Lattner | bc5d414 | 2003-07-23 17:02:11 +0000 | [diff] [blame] | 1190 | // If bits are being compared against that are and'd out, then the |
| 1191 | // comparison can never succeed! |
| 1192 | if (!(*CI & *~*BOC)->isNullValue()) |
| 1193 | return ReplaceInstUsesWith(I, ConstantBool::get(isSetNE)); |
Chris Lattner | 934754b | 2003-08-13 05:33:12 +0000 | [diff] [blame] | 1194 | |
| 1195 | // Replace (and X, (1 << size(X)-1) != 0) with x < 0, converting X |
| 1196 | // to be a signed value as appropriate. |
| 1197 | if (isSignBit(BOC)) { |
| 1198 | Value *X = BO->getOperand(0); |
| 1199 | // If 'X' is not signed, insert a cast now... |
| 1200 | if (!BOC->getType()->isSigned()) { |
| 1201 | const Type *DestTy; |
| 1202 | switch (BOC->getType()->getPrimitiveID()) { |
| 1203 | case Type::UByteTyID: DestTy = Type::SByteTy; break; |
| 1204 | case Type::UShortTyID: DestTy = Type::ShortTy; break; |
| 1205 | case Type::UIntTyID: DestTy = Type::IntTy; break; |
| 1206 | case Type::ULongTyID: DestTy = Type::LongTy; break; |
| 1207 | default: assert(0 && "Invalid unsigned integer type!"); abort(); |
| 1208 | } |
| 1209 | CastInst *NewCI = new CastInst(X,DestTy,X->getName()+".signed"); |
| 1210 | InsertNewInstBefore(NewCI, I); |
| 1211 | X = NewCI; |
| 1212 | } |
| 1213 | return new SetCondInst(isSetNE ? Instruction::SetLT : |
| 1214 | Instruction::SetGE, X, |
| 1215 | Constant::getNullValue(X->getType())); |
| 1216 | } |
Chris Lattner | bc5d414 | 2003-07-23 17:02:11 +0000 | [diff] [blame] | 1217 | } |
Chris Lattner | 934754b | 2003-08-13 05:33:12 +0000 | [diff] [blame] | 1218 | default: break; |
| 1219 | } |
| 1220 | } |
Chris Lattner | 40f5d70 | 2003-06-04 05:10:11 +0000 | [diff] [blame] | 1221 | } |
Chris Lattner | 074d84c | 2003-06-01 03:35:25 +0000 | [diff] [blame] | 1222 | |
Chris Lattner | 8b17094 | 2002-08-09 23:47:40 +0000 | [diff] [blame] | 1223 | // Check to see if we are comparing against the minimum or maximum value... |
Chris Lattner | 233f7dc | 2002-08-12 21:17:25 +0000 | [diff] [blame] | 1224 | if (CI->isMinValue()) { |
Chris Lattner | 8b17094 | 2002-08-09 23:47:40 +0000 | [diff] [blame] | 1225 | if (I.getOpcode() == Instruction::SetLT) // A < MIN -> FALSE |
| 1226 | return ReplaceInstUsesWith(I, ConstantBool::False); |
| 1227 | if (I.getOpcode() == Instruction::SetGE) // A >= MIN -> TRUE |
| 1228 | return ReplaceInstUsesWith(I, ConstantBool::True); |
| 1229 | if (I.getOpcode() == Instruction::SetLE) // A <= MIN -> A == MIN |
| 1230 | return BinaryOperator::create(Instruction::SetEQ, Op0,Op1, I.getName()); |
| 1231 | if (I.getOpcode() == Instruction::SetGT) // A > MIN -> A != MIN |
| 1232 | return BinaryOperator::create(Instruction::SetNE, Op0,Op1, I.getName()); |
| 1233 | |
Chris Lattner | 233f7dc | 2002-08-12 21:17:25 +0000 | [diff] [blame] | 1234 | } else if (CI->isMaxValue()) { |
Chris Lattner | 8b17094 | 2002-08-09 23:47:40 +0000 | [diff] [blame] | 1235 | if (I.getOpcode() == Instruction::SetGT) // A > MAX -> FALSE |
| 1236 | return ReplaceInstUsesWith(I, ConstantBool::False); |
| 1237 | if (I.getOpcode() == Instruction::SetLE) // A <= MAX -> TRUE |
| 1238 | return ReplaceInstUsesWith(I, ConstantBool::True); |
| 1239 | if (I.getOpcode() == Instruction::SetGE) // A >= MAX -> A == MAX |
| 1240 | return BinaryOperator::create(Instruction::SetEQ, Op0,Op1, I.getName()); |
| 1241 | if (I.getOpcode() == Instruction::SetLT) // A < MAX -> A != MAX |
| 1242 | return BinaryOperator::create(Instruction::SetNE, Op0,Op1, I.getName()); |
| 1243 | |
| 1244 | // Comparing against a value really close to min or max? |
| 1245 | } else if (isMinValuePlusOne(CI)) { |
| 1246 | if (I.getOpcode() == Instruction::SetLT) // A < MIN+1 -> A == MIN |
| 1247 | return BinaryOperator::create(Instruction::SetEQ, Op0, |
| 1248 | SubOne(CI), I.getName()); |
| 1249 | if (I.getOpcode() == Instruction::SetGE) // A >= MIN-1 -> A != MIN |
| 1250 | return BinaryOperator::create(Instruction::SetNE, Op0, |
| 1251 | SubOne(CI), I.getName()); |
| 1252 | |
| 1253 | } else if (isMaxValueMinusOne(CI)) { |
| 1254 | if (I.getOpcode() == Instruction::SetGT) // A > MAX-1 -> A == MAX |
| 1255 | return BinaryOperator::create(Instruction::SetEQ, Op0, |
| 1256 | AddOne(CI), I.getName()); |
| 1257 | if (I.getOpcode() == Instruction::SetLE) // A <= MAX-1 -> A != MAX |
| 1258 | return BinaryOperator::create(Instruction::SetNE, Op0, |
| 1259 | AddOne(CI), I.getName()); |
| 1260 | } |
Chris Lattner | 3f5b877 | 2002-05-06 16:14:14 +0000 | [diff] [blame] | 1261 | } |
| 1262 | |
Chris Lattner | 7e70829 | 2002-06-25 16:13:24 +0000 | [diff] [blame] | 1263 | return Changed ? &I : 0; |
Chris Lattner | 3f5b877 | 2002-05-06 16:14:14 +0000 | [diff] [blame] | 1264 | } |
| 1265 | |
| 1266 | |
| 1267 | |
Chris Lattner | ea34005 | 2003-03-10 19:16:08 +0000 | [diff] [blame] | 1268 | Instruction *InstCombiner::visitShiftInst(ShiftInst &I) { |
Chris Lattner | 7e70829 | 2002-06-25 16:13:24 +0000 | [diff] [blame] | 1269 | assert(I.getOperand(1)->getType() == Type::UByteTy); |
| 1270 | Value *Op0 = I.getOperand(0), *Op1 = I.getOperand(1); |
Chris Lattner | df17af1 | 2003-08-12 21:53:41 +0000 | [diff] [blame] | 1271 | bool isLeftShift = I.getOpcode() == Instruction::Shl; |
Chris Lattner | 3f5b877 | 2002-05-06 16:14:14 +0000 | [diff] [blame] | 1272 | |
| 1273 | // shl X, 0 == X and shr X, 0 == X |
| 1274 | // shl 0, X == 0 and shr 0, X == 0 |
| 1275 | if (Op1 == Constant::getNullValue(Type::UByteTy) || |
Chris Lattner | 233f7dc | 2002-08-12 21:17:25 +0000 | [diff] [blame] | 1276 | Op0 == Constant::getNullValue(Op0->getType())) |
| 1277 | return ReplaceInstUsesWith(I, Op0); |
Chris Lattner | 3f5b877 | 2002-05-06 16:14:14 +0000 | [diff] [blame] | 1278 | |
Chris Lattner | df17af1 | 2003-08-12 21:53:41 +0000 | [diff] [blame] | 1279 | // shr int -1, X = -1 (for any arithmetic shift rights of ~0) |
| 1280 | if (!isLeftShift) |
| 1281 | if (ConstantSInt *CSI = dyn_cast<ConstantSInt>(Op0)) |
| 1282 | if (CSI->isAllOnesValue()) |
| 1283 | return ReplaceInstUsesWith(I, CSI); |
| 1284 | |
Chris Lattner | 3f5b877 | 2002-05-06 16:14:14 +0000 | [diff] [blame] | 1285 | if (ConstantUInt *CUI = dyn_cast<ConstantUInt>(Op1)) { |
Chris Lattner | 08fd7ab | 2003-07-24 17:52:58 +0000 | [diff] [blame] | 1286 | // shl uint X, 32 = 0 and shr ubyte Y, 9 = 0, ... just don't eliminate shr |
| 1287 | // of a signed value. |
| 1288 | // |
Chris Lattner | ea34005 | 2003-03-10 19:16:08 +0000 | [diff] [blame] | 1289 | unsigned TypeBits = Op0->getType()->getPrimitiveSize()*8; |
| 1290 | if (CUI->getValue() >= TypeBits && |
Chris Lattner | df17af1 | 2003-08-12 21:53:41 +0000 | [diff] [blame] | 1291 | (!Op0->getType()->isSigned() || isLeftShift)) |
Chris Lattner | ea34005 | 2003-03-10 19:16:08 +0000 | [diff] [blame] | 1292 | return ReplaceInstUsesWith(I, Constant::getNullValue(Op0->getType())); |
Chris Lattner | f283608 | 2002-09-10 23:04:09 +0000 | [diff] [blame] | 1293 | |
Chris Lattner | e92d2f4 | 2003-08-13 04:18:28 +0000 | [diff] [blame] | 1294 | // ((X*C1) << C2) == (X * (C1 << C2)) |
| 1295 | if (BinaryOperator *BO = dyn_cast<BinaryOperator>(Op0)) |
| 1296 | if (BO->getOpcode() == Instruction::Mul && isLeftShift) |
| 1297 | if (Constant *BOOp = dyn_cast<Constant>(BO->getOperand(1))) |
| 1298 | return BinaryOperator::create(Instruction::Mul, BO->getOperand(0), |
| 1299 | *BOOp << *CUI); |
| 1300 | |
| 1301 | |
Chris Lattner | df17af1 | 2003-08-12 21:53:41 +0000 | [diff] [blame] | 1302 | // If the operand is an bitwise operator with a constant RHS, and the |
| 1303 | // shift is the only use, we can pull it out of the shift. |
Chris Lattner | fd05924 | 2003-10-15 16:48:29 +0000 | [diff] [blame] | 1304 | if (Op0->hasOneUse()) |
Chris Lattner | df17af1 | 2003-08-12 21:53:41 +0000 | [diff] [blame] | 1305 | if (BinaryOperator *Op0BO = dyn_cast<BinaryOperator>(Op0)) |
| 1306 | if (ConstantInt *Op0C = dyn_cast<ConstantInt>(Op0BO->getOperand(1))) { |
| 1307 | bool isValid = true; // Valid only for And, Or, Xor |
| 1308 | bool highBitSet = false; // Transform if high bit of constant set? |
| 1309 | |
| 1310 | switch (Op0BO->getOpcode()) { |
| 1311 | default: isValid = false; break; // Do not perform transform! |
| 1312 | case Instruction::Or: |
| 1313 | case Instruction::Xor: |
| 1314 | highBitSet = false; |
| 1315 | break; |
| 1316 | case Instruction::And: |
| 1317 | highBitSet = true; |
| 1318 | break; |
| 1319 | } |
| 1320 | |
| 1321 | // If this is a signed shift right, and the high bit is modified |
| 1322 | // by the logical operation, do not perform the transformation. |
| 1323 | // The highBitSet boolean indicates the value of the high bit of |
| 1324 | // the constant which would cause it to be modified for this |
| 1325 | // operation. |
| 1326 | // |
| 1327 | if (isValid && !isLeftShift && !I.getType()->isUnsigned()) { |
| 1328 | uint64_t Val = Op0C->getRawValue(); |
| 1329 | isValid = ((Val & (1 << (TypeBits-1))) != 0) == highBitSet; |
| 1330 | } |
| 1331 | |
| 1332 | if (isValid) { |
| 1333 | Constant *NewRHS = |
| 1334 | ConstantFoldShiftInstruction(I.getOpcode(), Op0C, CUI); |
| 1335 | |
| 1336 | Instruction *NewShift = |
| 1337 | new ShiftInst(I.getOpcode(), Op0BO->getOperand(0), CUI, |
| 1338 | Op0BO->getName()); |
| 1339 | Op0BO->setName(""); |
| 1340 | InsertNewInstBefore(NewShift, I); |
| 1341 | |
| 1342 | return BinaryOperator::create(Op0BO->getOpcode(), NewShift, |
| 1343 | NewRHS); |
| 1344 | } |
| 1345 | } |
| 1346 | |
Chris Lattner | 08fd7ab | 2003-07-24 17:52:58 +0000 | [diff] [blame] | 1347 | // If this is a shift of a shift, see if we can fold the two together... |
Chris Lattner | df17af1 | 2003-08-12 21:53:41 +0000 | [diff] [blame] | 1348 | if (ShiftInst *Op0SI = dyn_cast<ShiftInst>(Op0)) |
Chris Lattner | 943c713 | 2003-07-24 18:38:56 +0000 | [diff] [blame] | 1349 | if (ConstantUInt *ShiftAmt1C = |
| 1350 | dyn_cast<ConstantUInt>(Op0SI->getOperand(1))) { |
Chris Lattner | 08fd7ab | 2003-07-24 17:52:58 +0000 | [diff] [blame] | 1351 | unsigned ShiftAmt1 = ShiftAmt1C->getValue(); |
| 1352 | unsigned ShiftAmt2 = CUI->getValue(); |
| 1353 | |
| 1354 | // Check for (A << c1) << c2 and (A >> c1) >> c2 |
| 1355 | if (I.getOpcode() == Op0SI->getOpcode()) { |
| 1356 | unsigned Amt = ShiftAmt1+ShiftAmt2; // Fold into one big shift... |
| 1357 | return new ShiftInst(I.getOpcode(), Op0SI->getOperand(0), |
| 1358 | ConstantUInt::get(Type::UByteTy, Amt)); |
| 1359 | } |
| 1360 | |
Chris Lattner | 943c713 | 2003-07-24 18:38:56 +0000 | [diff] [blame] | 1361 | // Check for (A << c1) >> c2 or visaversa. If we are dealing with |
| 1362 | // signed types, we can only support the (A >> c1) << c2 configuration, |
| 1363 | // because it can not turn an arbitrary bit of A into a sign bit. |
Chris Lattner | df17af1 | 2003-08-12 21:53:41 +0000 | [diff] [blame] | 1364 | if (I.getType()->isUnsigned() || isLeftShift) { |
Chris Lattner | 08fd7ab | 2003-07-24 17:52:58 +0000 | [diff] [blame] | 1365 | // Calculate bitmask for what gets shifted off the edge... |
| 1366 | Constant *C = ConstantIntegral::getAllOnesValue(I.getType()); |
Chris Lattner | df17af1 | 2003-08-12 21:53:41 +0000 | [diff] [blame] | 1367 | if (isLeftShift) |
Chris Lattner | 08fd7ab | 2003-07-24 17:52:58 +0000 | [diff] [blame] | 1368 | C = ConstantExpr::getShift(Instruction::Shl, C, ShiftAmt1C); |
Chris Lattner | df17af1 | 2003-08-12 21:53:41 +0000 | [diff] [blame] | 1369 | else |
| 1370 | C = ConstantExpr::getShift(Instruction::Shr, C, ShiftAmt1C); |
Chris Lattner | 08fd7ab | 2003-07-24 17:52:58 +0000 | [diff] [blame] | 1371 | |
| 1372 | Instruction *Mask = |
| 1373 | BinaryOperator::create(Instruction::And, Op0SI->getOperand(0), |
| 1374 | C, Op0SI->getOperand(0)->getName()+".mask"); |
| 1375 | InsertNewInstBefore(Mask, I); |
| 1376 | |
| 1377 | // Figure out what flavor of shift we should use... |
| 1378 | if (ShiftAmt1 == ShiftAmt2) |
| 1379 | return ReplaceInstUsesWith(I, Mask); // (A << c) >> c === A & c2 |
| 1380 | else if (ShiftAmt1 < ShiftAmt2) { |
| 1381 | return new ShiftInst(I.getOpcode(), Mask, |
| 1382 | ConstantUInt::get(Type::UByteTy, ShiftAmt2-ShiftAmt1)); |
| 1383 | } else { |
| 1384 | return new ShiftInst(Op0SI->getOpcode(), Mask, |
| 1385 | ConstantUInt::get(Type::UByteTy, ShiftAmt1-ShiftAmt2)); |
| 1386 | } |
| 1387 | } |
| 1388 | } |
Chris Lattner | 3f5b877 | 2002-05-06 16:14:14 +0000 | [diff] [blame] | 1389 | } |
Chris Lattner | 6eaeb57 | 2002-10-08 16:16:40 +0000 | [diff] [blame] | 1390 | |
Chris Lattner | 3f5b877 | 2002-05-06 16:14:14 +0000 | [diff] [blame] | 1391 | return 0; |
| 1392 | } |
| 1393 | |
| 1394 | |
Chris Lattner | a1be566 | 2002-05-02 17:06:02 +0000 | [diff] [blame] | 1395 | // isEliminableCastOfCast - Return true if it is valid to eliminate the CI |
| 1396 | // instruction. |
| 1397 | // |
Chris Lattner | 24c8e38 | 2003-07-24 17:35:25 +0000 | [diff] [blame] | 1398 | static inline bool isEliminableCastOfCast(const Type *SrcTy, const Type *MidTy, |
| 1399 | const Type *DstTy) { |
Chris Lattner | a1be566 | 2002-05-02 17:06:02 +0000 | [diff] [blame] | 1400 | |
Chris Lattner | 8fd217c | 2002-08-02 20:00:25 +0000 | [diff] [blame] | 1401 | // It is legal to eliminate the instruction if casting A->B->A if the sizes |
| 1402 | // are identical and the bits don't get reinterpreted (for example |
Chris Lattner | 5cf6f11 | 2002-08-14 23:21:10 +0000 | [diff] [blame] | 1403 | // int->float->int would not be allowed) |
Misha Brukman | f117cc9 | 2003-05-20 18:45:36 +0000 | [diff] [blame] | 1404 | if (SrcTy == DstTy && SrcTy->isLosslesslyConvertibleTo(MidTy)) |
Chris Lattner | 8fd217c | 2002-08-02 20:00:25 +0000 | [diff] [blame] | 1405 | return true; |
Chris Lattner | a1be566 | 2002-05-02 17:06:02 +0000 | [diff] [blame] | 1406 | |
| 1407 | // Allow free casting and conversion of sizes as long as the sign doesn't |
| 1408 | // change... |
Chris Lattner | 0c4e886 | 2002-09-03 01:08:28 +0000 | [diff] [blame] | 1409 | if (SrcTy->isIntegral() && MidTy->isIntegral() && DstTy->isIntegral()) { |
Chris Lattner | 8fd217c | 2002-08-02 20:00:25 +0000 | [diff] [blame] | 1410 | unsigned SrcSize = SrcTy->getPrimitiveSize(); |
| 1411 | unsigned MidSize = MidTy->getPrimitiveSize(); |
| 1412 | unsigned DstSize = DstTy->getPrimitiveSize(); |
Chris Lattner | 8fd217c | 2002-08-02 20:00:25 +0000 | [diff] [blame] | 1413 | |
Chris Lattner | 3ecce66 | 2002-08-15 16:15:25 +0000 | [diff] [blame] | 1414 | // Cases where we are monotonically decreasing the size of the type are |
| 1415 | // always ok, regardless of what sign changes are going on. |
| 1416 | // |
Chris Lattner | 5cf6f11 | 2002-08-14 23:21:10 +0000 | [diff] [blame] | 1417 | if (SrcSize >= MidSize && MidSize >= DstSize) |
Chris Lattner | 8fd217c | 2002-08-02 20:00:25 +0000 | [diff] [blame] | 1418 | return true; |
Chris Lattner | 3ecce66 | 2002-08-15 16:15:25 +0000 | [diff] [blame] | 1419 | |
Chris Lattner | d06451f | 2002-09-23 23:39:43 +0000 | [diff] [blame] | 1420 | // Cases where the source and destination type are the same, but the middle |
| 1421 | // type is bigger are noops. |
| 1422 | // |
| 1423 | if (SrcSize == DstSize && MidSize > SrcSize) |
| 1424 | return true; |
| 1425 | |
Chris Lattner | 3ecce66 | 2002-08-15 16:15:25 +0000 | [diff] [blame] | 1426 | // If we are monotonically growing, things are more complex. |
| 1427 | // |
| 1428 | if (SrcSize <= MidSize && MidSize <= DstSize) { |
| 1429 | // We have eight combinations of signedness to worry about. Here's the |
| 1430 | // table: |
| 1431 | static const int SignTable[8] = { |
| 1432 | // CODE, SrcSigned, MidSigned, DstSigned, Comment |
| 1433 | 1, // U U U Always ok |
| 1434 | 1, // U U S Always ok |
| 1435 | 3, // U S U Ok iff SrcSize != MidSize |
| 1436 | 3, // U S S Ok iff SrcSize != MidSize |
| 1437 | 0, // S U U Never ok |
| 1438 | 2, // S U S Ok iff MidSize == DstSize |
| 1439 | 1, // S S U Always ok |
| 1440 | 1, // S S S Always ok |
| 1441 | }; |
| 1442 | |
| 1443 | // Choose an action based on the current entry of the signtable that this |
| 1444 | // cast of cast refers to... |
| 1445 | unsigned Row = SrcTy->isSigned()*4+MidTy->isSigned()*2+DstTy->isSigned(); |
| 1446 | switch (SignTable[Row]) { |
| 1447 | case 0: return false; // Never ok |
| 1448 | case 1: return true; // Always ok |
| 1449 | case 2: return MidSize == DstSize; // Ok iff MidSize == DstSize |
| 1450 | case 3: // Ok iff SrcSize != MidSize |
| 1451 | return SrcSize != MidSize || SrcTy == Type::BoolTy; |
| 1452 | default: assert(0 && "Bad entry in sign table!"); |
| 1453 | } |
Chris Lattner | 3ecce66 | 2002-08-15 16:15:25 +0000 | [diff] [blame] | 1454 | } |
Chris Lattner | 8fd217c | 2002-08-02 20:00:25 +0000 | [diff] [blame] | 1455 | } |
Chris Lattner | a1be566 | 2002-05-02 17:06:02 +0000 | [diff] [blame] | 1456 | |
| 1457 | // Otherwise, we cannot succeed. Specifically we do not want to allow things |
| 1458 | // like: short -> ushort -> uint, because this can create wrong results if |
| 1459 | // the input short is negative! |
| 1460 | // |
| 1461 | return false; |
| 1462 | } |
| 1463 | |
Chris Lattner | 24c8e38 | 2003-07-24 17:35:25 +0000 | [diff] [blame] | 1464 | static bool ValueRequiresCast(const Value *V, const Type *Ty) { |
| 1465 | if (V->getType() == Ty || isa<Constant>(V)) return false; |
| 1466 | if (const CastInst *CI = dyn_cast<CastInst>(V)) |
| 1467 | if (isEliminableCastOfCast(CI->getOperand(0)->getType(), CI->getType(), Ty)) |
| 1468 | return false; |
| 1469 | return true; |
| 1470 | } |
| 1471 | |
| 1472 | /// InsertOperandCastBefore - This inserts a cast of V to DestTy before the |
| 1473 | /// InsertBefore instruction. This is specialized a bit to avoid inserting |
| 1474 | /// casts that are known to not do anything... |
| 1475 | /// |
| 1476 | Value *InstCombiner::InsertOperandCastBefore(Value *V, const Type *DestTy, |
| 1477 | Instruction *InsertBefore) { |
| 1478 | if (V->getType() == DestTy) return V; |
| 1479 | if (Constant *C = dyn_cast<Constant>(V)) |
| 1480 | return ConstantExpr::getCast(C, DestTy); |
| 1481 | |
| 1482 | CastInst *CI = new CastInst(V, DestTy, V->getName()); |
| 1483 | InsertNewInstBefore(CI, *InsertBefore); |
| 1484 | return CI; |
| 1485 | } |
Chris Lattner | a1be566 | 2002-05-02 17:06:02 +0000 | [diff] [blame] | 1486 | |
| 1487 | // CastInst simplification |
Chris Lattner | dd841ae | 2002-04-18 17:39:14 +0000 | [diff] [blame] | 1488 | // |
Chris Lattner | 7e70829 | 2002-06-25 16:13:24 +0000 | [diff] [blame] | 1489 | Instruction *InstCombiner::visitCastInst(CastInst &CI) { |
Chris Lattner | 79d35b3 | 2003-06-23 21:59:52 +0000 | [diff] [blame] | 1490 | Value *Src = CI.getOperand(0); |
| 1491 | |
Chris Lattner | a1be566 | 2002-05-02 17:06:02 +0000 | [diff] [blame] | 1492 | // If the user is casting a value to the same type, eliminate this cast |
| 1493 | // instruction... |
Chris Lattner | 79d35b3 | 2003-06-23 21:59:52 +0000 | [diff] [blame] | 1494 | if (CI.getType() == Src->getType()) |
| 1495 | return ReplaceInstUsesWith(CI, Src); |
Chris Lattner | a1be566 | 2002-05-02 17:06:02 +0000 | [diff] [blame] | 1496 | |
Chris Lattner | a1be566 | 2002-05-02 17:06:02 +0000 | [diff] [blame] | 1497 | // If casting the result of another cast instruction, try to eliminate this |
| 1498 | // one! |
| 1499 | // |
Chris Lattner | 79d35b3 | 2003-06-23 21:59:52 +0000 | [diff] [blame] | 1500 | if (CastInst *CSrc = dyn_cast<CastInst>(Src)) { |
Chris Lattner | 24c8e38 | 2003-07-24 17:35:25 +0000 | [diff] [blame] | 1501 | if (isEliminableCastOfCast(CSrc->getOperand(0)->getType(), |
| 1502 | CSrc->getType(), CI.getType())) { |
Chris Lattner | a1be566 | 2002-05-02 17:06:02 +0000 | [diff] [blame] | 1503 | // This instruction now refers directly to the cast's src operand. This |
| 1504 | // has a good chance of making CSrc dead. |
Chris Lattner | 7e70829 | 2002-06-25 16:13:24 +0000 | [diff] [blame] | 1505 | CI.setOperand(0, CSrc->getOperand(0)); |
| 1506 | return &CI; |
Chris Lattner | a1be566 | 2002-05-02 17:06:02 +0000 | [diff] [blame] | 1507 | } |
| 1508 | |
Chris Lattner | 8fd217c | 2002-08-02 20:00:25 +0000 | [diff] [blame] | 1509 | // If this is an A->B->A cast, and we are dealing with integral types, try |
| 1510 | // to convert this into a logical 'and' instruction. |
| 1511 | // |
| 1512 | if (CSrc->getOperand(0)->getType() == CI.getType() && |
Chris Lattner | 0c4e886 | 2002-09-03 01:08:28 +0000 | [diff] [blame] | 1513 | CI.getType()->isInteger() && CSrc->getType()->isInteger() && |
Chris Lattner | 8fd217c | 2002-08-02 20:00:25 +0000 | [diff] [blame] | 1514 | CI.getType()->isUnsigned() && CSrc->getType()->isUnsigned() && |
| 1515 | CSrc->getType()->getPrimitiveSize() < CI.getType()->getPrimitiveSize()){ |
| 1516 | assert(CSrc->getType() != Type::ULongTy && |
| 1517 | "Cannot have type bigger than ulong!"); |
Chris Lattner | bd4ecf7 | 2003-05-26 23:41:32 +0000 | [diff] [blame] | 1518 | uint64_t AndValue = (1ULL << CSrc->getType()->getPrimitiveSize()*8)-1; |
Chris Lattner | 8fd217c | 2002-08-02 20:00:25 +0000 | [diff] [blame] | 1519 | Constant *AndOp = ConstantUInt::get(CI.getType(), AndValue); |
| 1520 | return BinaryOperator::create(Instruction::And, CSrc->getOperand(0), |
| 1521 | AndOp); |
| 1522 | } |
| 1523 | } |
| 1524 | |
Chris Lattner | 797249b | 2003-06-21 23:12:02 +0000 | [diff] [blame] | 1525 | // If casting the result of a getelementptr instruction with no offset, turn |
| 1526 | // this into a cast of the original pointer! |
| 1527 | // |
Chris Lattner | 79d35b3 | 2003-06-23 21:59:52 +0000 | [diff] [blame] | 1528 | if (GetElementPtrInst *GEP = dyn_cast<GetElementPtrInst>(Src)) { |
Chris Lattner | 797249b | 2003-06-21 23:12:02 +0000 | [diff] [blame] | 1529 | bool AllZeroOperands = true; |
| 1530 | for (unsigned i = 1, e = GEP->getNumOperands(); i != e; ++i) |
| 1531 | if (!isa<Constant>(GEP->getOperand(i)) || |
| 1532 | !cast<Constant>(GEP->getOperand(i))->isNullValue()) { |
| 1533 | AllZeroOperands = false; |
| 1534 | break; |
| 1535 | } |
| 1536 | if (AllZeroOperands) { |
| 1537 | CI.setOperand(0, GEP->getOperand(0)); |
| 1538 | return &CI; |
| 1539 | } |
| 1540 | } |
| 1541 | |
Chris Lattner | bc61e66 | 2003-11-02 05:57:39 +0000 | [diff] [blame] | 1542 | // If we are casting a malloc or alloca to a pointer to a type of the same |
| 1543 | // size, rewrite the allocation instruction to allocate the "right" type. |
| 1544 | // |
| 1545 | if (AllocationInst *AI = dyn_cast<AllocationInst>(Src)) |
Chris Lattner | fc07a34 | 2003-11-02 06:54:48 +0000 | [diff] [blame^] | 1546 | if (AI->hasOneUse() && !AI->isArrayAllocation()) |
Chris Lattner | bc61e66 | 2003-11-02 05:57:39 +0000 | [diff] [blame] | 1547 | if (const PointerType *PTy = dyn_cast<PointerType>(CI.getType())) { |
| 1548 | // Get the type really allocated and the type casted to... |
| 1549 | const Type *AllocElTy = AI->getAllocatedType(); |
| 1550 | unsigned AllocElTySize = TD->getTypeSize(AllocElTy); |
| 1551 | const Type *CastElTy = PTy->getElementType(); |
| 1552 | unsigned CastElTySize = TD->getTypeSize(CastElTy); |
| 1553 | |
| 1554 | // If the allocation is for an even multiple of the cast type size |
| 1555 | if (AllocElTySize % CastElTySize == 0) { |
| 1556 | Value *Amt = ConstantUInt::get(Type::UIntTy, |
| 1557 | AllocElTySize/CastElTySize); |
| 1558 | std::string Name = AI->getName(); AI->setName(""); |
| 1559 | AllocationInst *New; |
| 1560 | if (isa<MallocInst>(AI)) |
| 1561 | New = new MallocInst(CastElTy, Amt, Name); |
| 1562 | else |
| 1563 | New = new AllocaInst(CastElTy, Amt, Name); |
| 1564 | InsertNewInstBefore(New, CI); |
| 1565 | return ReplaceInstUsesWith(CI, New); |
| 1566 | } |
| 1567 | } |
| 1568 | |
Chris Lattner | 24c8e38 | 2003-07-24 17:35:25 +0000 | [diff] [blame] | 1569 | // If the source value is an instruction with only this use, we can attempt to |
| 1570 | // propagate the cast into the instruction. Also, only handle integral types |
| 1571 | // for now. |
| 1572 | if (Instruction *SrcI = dyn_cast<Instruction>(Src)) |
Chris Lattner | fd05924 | 2003-10-15 16:48:29 +0000 | [diff] [blame] | 1573 | if (SrcI->hasOneUse() && Src->getType()->isIntegral() && |
Chris Lattner | 24c8e38 | 2003-07-24 17:35:25 +0000 | [diff] [blame] | 1574 | CI.getType()->isInteger()) { // Don't mess with casts to bool here |
| 1575 | const Type *DestTy = CI.getType(); |
| 1576 | unsigned SrcBitSize = getTypeSizeInBits(Src->getType()); |
| 1577 | unsigned DestBitSize = getTypeSizeInBits(DestTy); |
| 1578 | |
| 1579 | Value *Op0 = SrcI->getNumOperands() > 0 ? SrcI->getOperand(0) : 0; |
| 1580 | Value *Op1 = SrcI->getNumOperands() > 1 ? SrcI->getOperand(1) : 0; |
| 1581 | |
| 1582 | switch (SrcI->getOpcode()) { |
| 1583 | case Instruction::Add: |
| 1584 | case Instruction::Mul: |
| 1585 | case Instruction::And: |
| 1586 | case Instruction::Or: |
| 1587 | case Instruction::Xor: |
| 1588 | // If we are discarding information, or just changing the sign, rewrite. |
| 1589 | if (DestBitSize <= SrcBitSize && DestBitSize != 1) { |
| 1590 | // Don't insert two casts if they cannot be eliminated. We allow two |
| 1591 | // casts to be inserted if the sizes are the same. This could only be |
| 1592 | // converting signedness, which is a noop. |
| 1593 | if (DestBitSize == SrcBitSize || !ValueRequiresCast(Op1, DestTy) || |
| 1594 | !ValueRequiresCast(Op0, DestTy)) { |
| 1595 | Value *Op0c = InsertOperandCastBefore(Op0, DestTy, SrcI); |
| 1596 | Value *Op1c = InsertOperandCastBefore(Op1, DestTy, SrcI); |
| 1597 | return BinaryOperator::create(cast<BinaryOperator>(SrcI) |
| 1598 | ->getOpcode(), Op0c, Op1c); |
| 1599 | } |
| 1600 | } |
| 1601 | break; |
| 1602 | case Instruction::Shl: |
| 1603 | // Allow changing the sign of the source operand. Do not allow changing |
| 1604 | // the size of the shift, UNLESS the shift amount is a constant. We |
| 1605 | // mush not change variable sized shifts to a smaller size, because it |
| 1606 | // is undefined to shift more bits out than exist in the value. |
| 1607 | if (DestBitSize == SrcBitSize || |
| 1608 | (DestBitSize < SrcBitSize && isa<Constant>(Op1))) { |
| 1609 | Value *Op0c = InsertOperandCastBefore(Op0, DestTy, SrcI); |
| 1610 | return new ShiftInst(Instruction::Shl, Op0c, Op1); |
| 1611 | } |
| 1612 | break; |
| 1613 | } |
| 1614 | } |
| 1615 | |
Chris Lattner | dd841ae | 2002-04-18 17:39:14 +0000 | [diff] [blame] | 1616 | return 0; |
Chris Lattner | 8a2a311 | 2001-12-14 16:52:21 +0000 | [diff] [blame] | 1617 | } |
| 1618 | |
Chris Lattner | 9fe3886 | 2003-06-19 17:00:31 +0000 | [diff] [blame] | 1619 | // CallInst simplification |
| 1620 | // |
| 1621 | Instruction *InstCombiner::visitCallInst(CallInst &CI) { |
Chris Lattner | a44d8a2 | 2003-10-07 22:32:43 +0000 | [diff] [blame] | 1622 | return visitCallSite(&CI); |
Chris Lattner | 9fe3886 | 2003-06-19 17:00:31 +0000 | [diff] [blame] | 1623 | } |
| 1624 | |
| 1625 | // InvokeInst simplification |
| 1626 | // |
| 1627 | Instruction *InstCombiner::visitInvokeInst(InvokeInst &II) { |
Chris Lattner | a44d8a2 | 2003-10-07 22:32:43 +0000 | [diff] [blame] | 1628 | return visitCallSite(&II); |
Chris Lattner | 9fe3886 | 2003-06-19 17:00:31 +0000 | [diff] [blame] | 1629 | } |
| 1630 | |
| 1631 | // getPromotedType - Return the specified type promoted as it would be to pass |
| 1632 | // though a va_arg area... |
| 1633 | static const Type *getPromotedType(const Type *Ty) { |
| 1634 | switch (Ty->getPrimitiveID()) { |
| 1635 | case Type::SByteTyID: |
| 1636 | case Type::ShortTyID: return Type::IntTy; |
| 1637 | case Type::UByteTyID: |
| 1638 | case Type::UShortTyID: return Type::UIntTy; |
| 1639 | case Type::FloatTyID: return Type::DoubleTy; |
| 1640 | default: return Ty; |
| 1641 | } |
| 1642 | } |
| 1643 | |
Chris Lattner | a44d8a2 | 2003-10-07 22:32:43 +0000 | [diff] [blame] | 1644 | // visitCallSite - Improvements for call and invoke instructions. |
| 1645 | // |
| 1646 | Instruction *InstCombiner::visitCallSite(CallSite CS) { |
Chris Lattner | 6c266db | 2003-10-07 22:54:13 +0000 | [diff] [blame] | 1647 | bool Changed = false; |
| 1648 | |
| 1649 | // If the callee is a constexpr cast of a function, attempt to move the cast |
| 1650 | // to the arguments of the call/invoke. |
Chris Lattner | a44d8a2 | 2003-10-07 22:32:43 +0000 | [diff] [blame] | 1651 | if (transformConstExprCastCall(CS)) return 0; |
| 1652 | |
Chris Lattner | 6c266db | 2003-10-07 22:54:13 +0000 | [diff] [blame] | 1653 | Value *Callee = CS.getCalledValue(); |
| 1654 | const PointerType *PTy = cast<PointerType>(Callee->getType()); |
| 1655 | const FunctionType *FTy = cast<FunctionType>(PTy->getElementType()); |
| 1656 | if (FTy->isVarArg()) { |
| 1657 | // See if we can optimize any arguments passed through the varargs area of |
| 1658 | // the call. |
| 1659 | for (CallSite::arg_iterator I = CS.arg_begin()+FTy->getNumParams(), |
| 1660 | E = CS.arg_end(); I != E; ++I) |
| 1661 | if (CastInst *CI = dyn_cast<CastInst>(*I)) { |
| 1662 | // If this cast does not effect the value passed through the varargs |
| 1663 | // area, we can eliminate the use of the cast. |
| 1664 | Value *Op = CI->getOperand(0); |
| 1665 | if (CI->getType()->isLosslesslyConvertibleTo(Op->getType())) { |
| 1666 | *I = Op; |
| 1667 | Changed = true; |
| 1668 | } |
| 1669 | } |
| 1670 | } |
Chris Lattner | a44d8a2 | 2003-10-07 22:32:43 +0000 | [diff] [blame] | 1671 | |
Chris Lattner | 6c266db | 2003-10-07 22:54:13 +0000 | [diff] [blame] | 1672 | return Changed ? CS.getInstruction() : 0; |
Chris Lattner | a44d8a2 | 2003-10-07 22:32:43 +0000 | [diff] [blame] | 1673 | } |
| 1674 | |
Chris Lattner | 9fe3886 | 2003-06-19 17:00:31 +0000 | [diff] [blame] | 1675 | // transformConstExprCastCall - If the callee is a constexpr cast of a function, |
| 1676 | // attempt to move the cast to the arguments of the call/invoke. |
| 1677 | // |
| 1678 | bool InstCombiner::transformConstExprCastCall(CallSite CS) { |
| 1679 | if (!isa<ConstantExpr>(CS.getCalledValue())) return false; |
| 1680 | ConstantExpr *CE = cast<ConstantExpr>(CS.getCalledValue()); |
| 1681 | if (CE->getOpcode() != Instruction::Cast || |
| 1682 | !isa<ConstantPointerRef>(CE->getOperand(0))) |
| 1683 | return false; |
| 1684 | ConstantPointerRef *CPR = cast<ConstantPointerRef>(CE->getOperand(0)); |
| 1685 | if (!isa<Function>(CPR->getValue())) return false; |
| 1686 | Function *Callee = cast<Function>(CPR->getValue()); |
| 1687 | Instruction *Caller = CS.getInstruction(); |
| 1688 | |
| 1689 | // Okay, this is a cast from a function to a different type. Unless doing so |
| 1690 | // would cause a type conversion of one of our arguments, change this call to |
| 1691 | // be a direct call with arguments casted to the appropriate types. |
| 1692 | // |
| 1693 | const FunctionType *FT = Callee->getFunctionType(); |
| 1694 | const Type *OldRetTy = Caller->getType(); |
| 1695 | |
| 1696 | if (Callee->isExternal() && |
| 1697 | !OldRetTy->isLosslesslyConvertibleTo(FT->getReturnType())) |
| 1698 | return false; // Cannot transform this return value... |
| 1699 | |
| 1700 | unsigned NumActualArgs = unsigned(CS.arg_end()-CS.arg_begin()); |
| 1701 | unsigned NumCommonArgs = std::min(FT->getNumParams(), NumActualArgs); |
| 1702 | |
| 1703 | CallSite::arg_iterator AI = CS.arg_begin(); |
| 1704 | for (unsigned i = 0, e = NumCommonArgs; i != e; ++i, ++AI) { |
| 1705 | const Type *ParamTy = FT->getParamType(i); |
| 1706 | bool isConvertible = (*AI)->getType()->isLosslesslyConvertibleTo(ParamTy); |
| 1707 | if (Callee->isExternal() && !isConvertible) return false; |
| 1708 | } |
| 1709 | |
| 1710 | if (FT->getNumParams() < NumActualArgs && !FT->isVarArg() && |
| 1711 | Callee->isExternal()) |
| 1712 | return false; // Do not delete arguments unless we have a function body... |
| 1713 | |
| 1714 | // Okay, we decided that this is a safe thing to do: go ahead and start |
| 1715 | // inserting cast instructions as necessary... |
| 1716 | std::vector<Value*> Args; |
| 1717 | Args.reserve(NumActualArgs); |
| 1718 | |
| 1719 | AI = CS.arg_begin(); |
| 1720 | for (unsigned i = 0; i != NumCommonArgs; ++i, ++AI) { |
| 1721 | const Type *ParamTy = FT->getParamType(i); |
| 1722 | if ((*AI)->getType() == ParamTy) { |
| 1723 | Args.push_back(*AI); |
| 1724 | } else { |
| 1725 | Instruction *Cast = new CastInst(*AI, ParamTy, "tmp"); |
| 1726 | InsertNewInstBefore(Cast, *Caller); |
| 1727 | Args.push_back(Cast); |
| 1728 | } |
| 1729 | } |
| 1730 | |
| 1731 | // If the function takes more arguments than the call was taking, add them |
| 1732 | // now... |
| 1733 | for (unsigned i = NumCommonArgs; i != FT->getNumParams(); ++i) |
| 1734 | Args.push_back(Constant::getNullValue(FT->getParamType(i))); |
| 1735 | |
| 1736 | // If we are removing arguments to the function, emit an obnoxious warning... |
| 1737 | if (FT->getNumParams() < NumActualArgs) |
| 1738 | if (!FT->isVarArg()) { |
| 1739 | std::cerr << "WARNING: While resolving call to function '" |
| 1740 | << Callee->getName() << "' arguments were dropped!\n"; |
| 1741 | } else { |
| 1742 | // Add all of the arguments in their promoted form to the arg list... |
| 1743 | for (unsigned i = FT->getNumParams(); i != NumActualArgs; ++i, ++AI) { |
| 1744 | const Type *PTy = getPromotedType((*AI)->getType()); |
| 1745 | if (PTy != (*AI)->getType()) { |
| 1746 | // Must promote to pass through va_arg area! |
| 1747 | Instruction *Cast = new CastInst(*AI, PTy, "tmp"); |
| 1748 | InsertNewInstBefore(Cast, *Caller); |
| 1749 | Args.push_back(Cast); |
| 1750 | } else { |
| 1751 | Args.push_back(*AI); |
| 1752 | } |
| 1753 | } |
| 1754 | } |
| 1755 | |
| 1756 | if (FT->getReturnType() == Type::VoidTy) |
| 1757 | Caller->setName(""); // Void type should not have a name... |
| 1758 | |
| 1759 | Instruction *NC; |
| 1760 | if (InvokeInst *II = dyn_cast<InvokeInst>(Caller)) { |
| 1761 | NC = new InvokeInst(Callee, II->getNormalDest(), II->getExceptionalDest(), |
| 1762 | Args, Caller->getName(), Caller); |
| 1763 | } else { |
| 1764 | NC = new CallInst(Callee, Args, Caller->getName(), Caller); |
| 1765 | } |
| 1766 | |
| 1767 | // Insert a cast of the return type as necessary... |
| 1768 | Value *NV = NC; |
| 1769 | if (Caller->getType() != NV->getType() && !Caller->use_empty()) { |
| 1770 | if (NV->getType() != Type::VoidTy) { |
| 1771 | NV = NC = new CastInst(NC, Caller->getType(), "tmp"); |
Chris Lattner | bb60904 | 2003-10-30 00:46:41 +0000 | [diff] [blame] | 1772 | |
| 1773 | // If this is an invoke instruction, we should insert it after the first |
| 1774 | // non-phi, instruction in the normal successor block. |
| 1775 | if (InvokeInst *II = dyn_cast<InvokeInst>(Caller)) { |
| 1776 | BasicBlock::iterator I = II->getNormalDest()->begin(); |
| 1777 | while (isa<PHINode>(I)) ++I; |
| 1778 | InsertNewInstBefore(NC, *I); |
| 1779 | } else { |
| 1780 | // Otherwise, it's a call, just insert cast right after the call instr |
| 1781 | InsertNewInstBefore(NC, *Caller); |
| 1782 | } |
Chris Lattner | 9fe3886 | 2003-06-19 17:00:31 +0000 | [diff] [blame] | 1783 | AddUsesToWorkList(*Caller); |
| 1784 | } else { |
| 1785 | NV = Constant::getNullValue(Caller->getType()); |
| 1786 | } |
| 1787 | } |
| 1788 | |
| 1789 | if (Caller->getType() != Type::VoidTy && !Caller->use_empty()) |
| 1790 | Caller->replaceAllUsesWith(NV); |
| 1791 | Caller->getParent()->getInstList().erase(Caller); |
| 1792 | removeFromWorkList(Caller); |
| 1793 | return true; |
| 1794 | } |
| 1795 | |
| 1796 | |
Chris Lattner | a1be566 | 2002-05-02 17:06:02 +0000 | [diff] [blame] | 1797 | |
Chris Lattner | 473945d | 2002-05-06 18:06:38 +0000 | [diff] [blame] | 1798 | // PHINode simplification |
| 1799 | // |
Chris Lattner | 7e70829 | 2002-06-25 16:13:24 +0000 | [diff] [blame] | 1800 | Instruction *InstCombiner::visitPHINode(PHINode &PN) { |
Chris Lattner | 473945d | 2002-05-06 18:06:38 +0000 | [diff] [blame] | 1801 | // If the PHI node only has one incoming value, eliminate the PHI node... |
Chris Lattner | 233f7dc | 2002-08-12 21:17:25 +0000 | [diff] [blame] | 1802 | if (PN.getNumIncomingValues() == 1) |
| 1803 | return ReplaceInstUsesWith(PN, PN.getIncomingValue(0)); |
Chris Lattner | f02c468 | 2002-08-20 15:35:35 +0000 | [diff] [blame] | 1804 | |
| 1805 | // Otherwise if all of the incoming values are the same for the PHI, replace |
| 1806 | // the PHI node with the incoming value. |
| 1807 | // |
Chris Lattner | c20e245 | 2002-08-22 20:22:01 +0000 | [diff] [blame] | 1808 | Value *InVal = 0; |
| 1809 | for (unsigned i = 0, e = PN.getNumIncomingValues(); i != e; ++i) |
| 1810 | if (PN.getIncomingValue(i) != &PN) // Not the PHI node itself... |
| 1811 | if (InVal && PN.getIncomingValue(i) != InVal) |
| 1812 | return 0; // Not the same, bail out. |
| 1813 | else |
| 1814 | InVal = PN.getIncomingValue(i); |
| 1815 | |
| 1816 | // The only case that could cause InVal to be null is if we have a PHI node |
| 1817 | // that only has entries for itself. In this case, there is no entry into the |
| 1818 | // loop, so kill the PHI. |
| 1819 | // |
| 1820 | if (InVal == 0) InVal = Constant::getNullValue(PN.getType()); |
Chris Lattner | 473945d | 2002-05-06 18:06:38 +0000 | [diff] [blame] | 1821 | |
Chris Lattner | f02c468 | 2002-08-20 15:35:35 +0000 | [diff] [blame] | 1822 | // All of the incoming values are the same, replace the PHI node now. |
| 1823 | return ReplaceInstUsesWith(PN, InVal); |
Chris Lattner | 473945d | 2002-05-06 18:06:38 +0000 | [diff] [blame] | 1824 | } |
| 1825 | |
Chris Lattner | a1be566 | 2002-05-02 17:06:02 +0000 | [diff] [blame] | 1826 | |
Chris Lattner | 7e70829 | 2002-06-25 16:13:24 +0000 | [diff] [blame] | 1827 | Instruction *InstCombiner::visitGetElementPtrInst(GetElementPtrInst &GEP) { |
Chris Lattner | c54e2b8 | 2003-05-22 19:07:21 +0000 | [diff] [blame] | 1828 | // Is it 'getelementptr %P, long 0' or 'getelementptr %P' |
Chris Lattner | 7e70829 | 2002-06-25 16:13:24 +0000 | [diff] [blame] | 1829 | // If so, eliminate the noop. |
Chris Lattner | 90ac28c | 2002-08-02 19:29:35 +0000 | [diff] [blame] | 1830 | if ((GEP.getNumOperands() == 2 && |
Chris Lattner | 3cac88a | 2002-09-11 01:21:33 +0000 | [diff] [blame] | 1831 | GEP.getOperand(1) == Constant::getNullValue(Type::LongTy)) || |
Chris Lattner | 233f7dc | 2002-08-12 21:17:25 +0000 | [diff] [blame] | 1832 | GEP.getNumOperands() == 1) |
| 1833 | return ReplaceInstUsesWith(GEP, GEP.getOperand(0)); |
Chris Lattner | a1be566 | 2002-05-02 17:06:02 +0000 | [diff] [blame] | 1834 | |
Chris Lattner | 90ac28c | 2002-08-02 19:29:35 +0000 | [diff] [blame] | 1835 | // Combine Indices - If the source pointer to this getelementptr instruction |
| 1836 | // is a getelementptr instruction, combine the indices of the two |
| 1837 | // getelementptr instructions into a single instruction. |
| 1838 | // |
Chris Lattner | 9b76123 | 2002-08-17 22:21:59 +0000 | [diff] [blame] | 1839 | if (GetElementPtrInst *Src = dyn_cast<GetElementPtrInst>(GEP.getOperand(0))) { |
Chris Lattner | 90ac28c | 2002-08-02 19:29:35 +0000 | [diff] [blame] | 1840 | std::vector<Value *> Indices; |
Chris Lattner | 8a2a311 | 2001-12-14 16:52:21 +0000 | [diff] [blame] | 1841 | |
Chris Lattner | 90ac28c | 2002-08-02 19:29:35 +0000 | [diff] [blame] | 1842 | // Can we combine the two pointer arithmetics offsets? |
Chris Lattner | c54e2b8 | 2003-05-22 19:07:21 +0000 | [diff] [blame] | 1843 | if (Src->getNumOperands() == 2 && isa<Constant>(Src->getOperand(1)) && |
| 1844 | isa<Constant>(GEP.getOperand(1))) { |
Chris Lattner | decd081 | 2003-03-05 22:33:14 +0000 | [diff] [blame] | 1845 | // Replace: gep (gep %P, long C1), long C2, ... |
| 1846 | // With: gep %P, long (C1+C2), ... |
Chris Lattner | 2a9c847 | 2003-05-27 16:40:51 +0000 | [diff] [blame] | 1847 | Value *Sum = ConstantExpr::get(Instruction::Add, |
| 1848 | cast<Constant>(Src->getOperand(1)), |
| 1849 | cast<Constant>(GEP.getOperand(1))); |
Chris Lattner | decd081 | 2003-03-05 22:33:14 +0000 | [diff] [blame] | 1850 | assert(Sum && "Constant folding of longs failed!?"); |
| 1851 | GEP.setOperand(0, Src->getOperand(0)); |
| 1852 | GEP.setOperand(1, Sum); |
| 1853 | AddUsesToWorkList(*Src); // Reduce use count of Src |
| 1854 | return &GEP; |
Chris Lattner | c54e2b8 | 2003-05-22 19:07:21 +0000 | [diff] [blame] | 1855 | } else if (Src->getNumOperands() == 2) { |
Chris Lattner | decd081 | 2003-03-05 22:33:14 +0000 | [diff] [blame] | 1856 | // Replace: gep (gep %P, long B), long A, ... |
| 1857 | // With: T = long A+B; gep %P, T, ... |
| 1858 | // |
| 1859 | Value *Sum = BinaryOperator::create(Instruction::Add, Src->getOperand(1), |
| 1860 | GEP.getOperand(1), |
| 1861 | Src->getName()+".sum", &GEP); |
| 1862 | GEP.setOperand(0, Src->getOperand(0)); |
| 1863 | GEP.setOperand(1, Sum); |
| 1864 | WorkList.push_back(cast<Instruction>(Sum)); |
| 1865 | return &GEP; |
Chris Lattner | 0188534 | 2002-11-04 16:43:32 +0000 | [diff] [blame] | 1866 | } else if (*GEP.idx_begin() == Constant::getNullValue(Type::LongTy) && |
Chris Lattner | dfcbf01 | 2002-09-17 21:05:42 +0000 | [diff] [blame] | 1867 | Src->getNumOperands() != 1) { |
Chris Lattner | 90ac28c | 2002-08-02 19:29:35 +0000 | [diff] [blame] | 1868 | // Otherwise we can do the fold if the first index of the GEP is a zero |
| 1869 | Indices.insert(Indices.end(), Src->idx_begin(), Src->idx_end()); |
| 1870 | Indices.insert(Indices.end(), GEP.idx_begin()+1, GEP.idx_end()); |
Chris Lattner | 0188534 | 2002-11-04 16:43:32 +0000 | [diff] [blame] | 1871 | } else if (Src->getOperand(Src->getNumOperands()-1) == |
| 1872 | Constant::getNullValue(Type::LongTy)) { |
| 1873 | // If the src gep ends with a constant array index, merge this get into |
| 1874 | // it, even if we have a non-zero array index. |
| 1875 | Indices.insert(Indices.end(), Src->idx_begin(), Src->idx_end()-1); |
| 1876 | Indices.insert(Indices.end(), GEP.idx_begin(), GEP.idx_end()); |
Chris Lattner | 90ac28c | 2002-08-02 19:29:35 +0000 | [diff] [blame] | 1877 | } |
| 1878 | |
| 1879 | if (!Indices.empty()) |
| 1880 | return new GetElementPtrInst(Src->getOperand(0), Indices, GEP.getName()); |
Chris Lattner | 9b76123 | 2002-08-17 22:21:59 +0000 | [diff] [blame] | 1881 | |
| 1882 | } else if (GlobalValue *GV = dyn_cast<GlobalValue>(GEP.getOperand(0))) { |
| 1883 | // GEP of global variable. If all of the indices for this GEP are |
| 1884 | // constants, we can promote this to a constexpr instead of an instruction. |
| 1885 | |
| 1886 | // Scan for nonconstants... |
| 1887 | std::vector<Constant*> Indices; |
| 1888 | User::op_iterator I = GEP.idx_begin(), E = GEP.idx_end(); |
| 1889 | for (; I != E && isa<Constant>(*I); ++I) |
| 1890 | Indices.push_back(cast<Constant>(*I)); |
| 1891 | |
| 1892 | if (I == E) { // If they are all constants... |
Chris Lattner | fb242b6 | 2003-04-16 22:40:51 +0000 | [diff] [blame] | 1893 | Constant *CE = |
Chris Lattner | 9b76123 | 2002-08-17 22:21:59 +0000 | [diff] [blame] | 1894 | ConstantExpr::getGetElementPtr(ConstantPointerRef::get(GV), Indices); |
| 1895 | |
| 1896 | // Replace all uses of the GEP with the new constexpr... |
| 1897 | return ReplaceInstUsesWith(GEP, CE); |
| 1898 | } |
Chris Lattner | 8a2a311 | 2001-12-14 16:52:21 +0000 | [diff] [blame] | 1899 | } |
| 1900 | |
Chris Lattner | 8a2a311 | 2001-12-14 16:52:21 +0000 | [diff] [blame] | 1901 | return 0; |
| 1902 | } |
| 1903 | |
Chris Lattner | 0864acf | 2002-11-04 16:18:53 +0000 | [diff] [blame] | 1904 | Instruction *InstCombiner::visitAllocationInst(AllocationInst &AI) { |
| 1905 | // Convert: malloc Ty, C - where C is a constant != 1 into: malloc [C x Ty], 1 |
| 1906 | if (AI.isArrayAllocation()) // Check C != 1 |
| 1907 | if (const ConstantUInt *C = dyn_cast<ConstantUInt>(AI.getArraySize())) { |
| 1908 | const Type *NewTy = ArrayType::get(AI.getAllocatedType(), C->getValue()); |
Chris Lattner | 0006bd7 | 2002-11-09 00:49:43 +0000 | [diff] [blame] | 1909 | AllocationInst *New = 0; |
Chris Lattner | 0864acf | 2002-11-04 16:18:53 +0000 | [diff] [blame] | 1910 | |
| 1911 | // Create and insert the replacement instruction... |
| 1912 | if (isa<MallocInst>(AI)) |
| 1913 | New = new MallocInst(NewTy, 0, AI.getName(), &AI); |
Chris Lattner | 0006bd7 | 2002-11-09 00:49:43 +0000 | [diff] [blame] | 1914 | else { |
| 1915 | assert(isa<AllocaInst>(AI) && "Unknown type of allocation inst!"); |
Chris Lattner | 0864acf | 2002-11-04 16:18:53 +0000 | [diff] [blame] | 1916 | New = new AllocaInst(NewTy, 0, AI.getName(), &AI); |
Chris Lattner | 0006bd7 | 2002-11-09 00:49:43 +0000 | [diff] [blame] | 1917 | } |
Chris Lattner | 0864acf | 2002-11-04 16:18:53 +0000 | [diff] [blame] | 1918 | |
| 1919 | // Scan to the end of the allocation instructions, to skip over a block of |
| 1920 | // allocas if possible... |
| 1921 | // |
| 1922 | BasicBlock::iterator It = New; |
| 1923 | while (isa<AllocationInst>(*It)) ++It; |
| 1924 | |
| 1925 | // Now that I is pointing to the first non-allocation-inst in the block, |
| 1926 | // insert our getelementptr instruction... |
| 1927 | // |
| 1928 | std::vector<Value*> Idx(2, Constant::getNullValue(Type::LongTy)); |
| 1929 | Value *V = new GetElementPtrInst(New, Idx, New->getName()+".sub", It); |
| 1930 | |
| 1931 | // Now make everything use the getelementptr instead of the original |
| 1932 | // allocation. |
| 1933 | ReplaceInstUsesWith(AI, V); |
| 1934 | return &AI; |
| 1935 | } |
| 1936 | return 0; |
| 1937 | } |
| 1938 | |
Chris Lattner | 833b8a4 | 2003-06-26 05:06:25 +0000 | [diff] [blame] | 1939 | /// GetGEPGlobalInitializer - Given a constant, and a getelementptr |
| 1940 | /// constantexpr, return the constant value being addressed by the constant |
| 1941 | /// expression, or null if something is funny. |
| 1942 | /// |
| 1943 | static Constant *GetGEPGlobalInitializer(Constant *C, ConstantExpr *CE) { |
| 1944 | if (CE->getOperand(1) != Constant::getNullValue(Type::LongTy)) |
| 1945 | return 0; // Do not allow stepping over the value! |
| 1946 | |
| 1947 | // Loop over all of the operands, tracking down which value we are |
| 1948 | // addressing... |
| 1949 | for (unsigned i = 2, e = CE->getNumOperands(); i != e; ++i) |
| 1950 | if (ConstantUInt *CU = dyn_cast<ConstantUInt>(CE->getOperand(i))) { |
| 1951 | ConstantStruct *CS = cast<ConstantStruct>(C); |
| 1952 | if (CU->getValue() >= CS->getValues().size()) return 0; |
| 1953 | C = cast<Constant>(CS->getValues()[CU->getValue()]); |
| 1954 | } else if (ConstantSInt *CS = dyn_cast<ConstantSInt>(CE->getOperand(i))) { |
| 1955 | ConstantArray *CA = cast<ConstantArray>(C); |
| 1956 | if ((uint64_t)CS->getValue() >= CA->getValues().size()) return 0; |
| 1957 | C = cast<Constant>(CA->getValues()[CS->getValue()]); |
| 1958 | } else |
| 1959 | return 0; |
| 1960 | return C; |
| 1961 | } |
| 1962 | |
| 1963 | Instruction *InstCombiner::visitLoadInst(LoadInst &LI) { |
| 1964 | Value *Op = LI.getOperand(0); |
| 1965 | if (ConstantPointerRef *CPR = dyn_cast<ConstantPointerRef>(Op)) |
| 1966 | Op = CPR->getValue(); |
| 1967 | |
| 1968 | // Instcombine load (constant global) into the value loaded... |
| 1969 | if (GlobalVariable *GV = dyn_cast<GlobalVariable>(Op)) |
Chris Lattner | 1ba5bcd | 2003-07-22 21:46:59 +0000 | [diff] [blame] | 1970 | if (GV->isConstant() && !GV->isExternal()) |
Chris Lattner | 833b8a4 | 2003-06-26 05:06:25 +0000 | [diff] [blame] | 1971 | return ReplaceInstUsesWith(LI, GV->getInitializer()); |
| 1972 | |
| 1973 | // Instcombine load (constantexpr_GEP global, 0, ...) into the value loaded... |
| 1974 | if (ConstantExpr *CE = dyn_cast<ConstantExpr>(Op)) |
| 1975 | if (CE->getOpcode() == Instruction::GetElementPtr) |
| 1976 | if (ConstantPointerRef *G=dyn_cast<ConstantPointerRef>(CE->getOperand(0))) |
| 1977 | if (GlobalVariable *GV = dyn_cast<GlobalVariable>(G->getValue())) |
Chris Lattner | 1ba5bcd | 2003-07-22 21:46:59 +0000 | [diff] [blame] | 1978 | if (GV->isConstant() && !GV->isExternal()) |
Chris Lattner | 833b8a4 | 2003-06-26 05:06:25 +0000 | [diff] [blame] | 1979 | if (Constant *V = GetGEPGlobalInitializer(GV->getInitializer(), CE)) |
| 1980 | return ReplaceInstUsesWith(LI, V); |
| 1981 | return 0; |
| 1982 | } |
| 1983 | |
| 1984 | |
Chris Lattner | c4d10eb | 2003-06-04 04:46:00 +0000 | [diff] [blame] | 1985 | Instruction *InstCombiner::visitBranchInst(BranchInst &BI) { |
| 1986 | // Change br (not X), label True, label False to: br X, label False, True |
Chris Lattner | 9b5fd22 | 2003-06-05 20:12:51 +0000 | [diff] [blame] | 1987 | if (BI.isConditional() && !isa<Constant>(BI.getCondition())) |
Chris Lattner | 40f5d70 | 2003-06-04 05:10:11 +0000 | [diff] [blame] | 1988 | if (Value *V = dyn_castNotVal(BI.getCondition())) { |
| 1989 | BasicBlock *TrueDest = BI.getSuccessor(0); |
| 1990 | BasicBlock *FalseDest = BI.getSuccessor(1); |
| 1991 | // Swap Destinations and condition... |
| 1992 | BI.setCondition(V); |
| 1993 | BI.setSuccessor(0, FalseDest); |
| 1994 | BI.setSuccessor(1, TrueDest); |
| 1995 | return &BI; |
| 1996 | } |
Chris Lattner | c4d10eb | 2003-06-04 04:46:00 +0000 | [diff] [blame] | 1997 | return 0; |
| 1998 | } |
Chris Lattner | 0864acf | 2002-11-04 16:18:53 +0000 | [diff] [blame] | 1999 | |
Chris Lattner | 8a2a311 | 2001-12-14 16:52:21 +0000 | [diff] [blame] | 2000 | |
Chris Lattner | 62b14df | 2002-09-02 04:59:56 +0000 | [diff] [blame] | 2001 | void InstCombiner::removeFromWorkList(Instruction *I) { |
| 2002 | WorkList.erase(std::remove(WorkList.begin(), WorkList.end(), I), |
| 2003 | WorkList.end()); |
| 2004 | } |
| 2005 | |
Chris Lattner | 7e70829 | 2002-06-25 16:13:24 +0000 | [diff] [blame] | 2006 | bool InstCombiner::runOnFunction(Function &F) { |
Chris Lattner | dd841ae | 2002-04-18 17:39:14 +0000 | [diff] [blame] | 2007 | bool Changed = false; |
Chris Lattner | bc61e66 | 2003-11-02 05:57:39 +0000 | [diff] [blame] | 2008 | TD = &getAnalysis<TargetData>(); |
Chris Lattner | 8a2a311 | 2001-12-14 16:52:21 +0000 | [diff] [blame] | 2009 | |
Chris Lattner | dd841ae | 2002-04-18 17:39:14 +0000 | [diff] [blame] | 2010 | WorkList.insert(WorkList.end(), inst_begin(F), inst_end(F)); |
Chris Lattner | 8a2a311 | 2001-12-14 16:52:21 +0000 | [diff] [blame] | 2011 | |
| 2012 | while (!WorkList.empty()) { |
| 2013 | Instruction *I = WorkList.back(); // Get an instruction from the worklist |
| 2014 | WorkList.pop_back(); |
| 2015 | |
Misha Brukman | a3bbcb5 | 2002-10-29 23:06:16 +0000 | [diff] [blame] | 2016 | // Check to see if we can DCE or ConstantPropagate the instruction... |
Chris Lattner | 62b14df | 2002-09-02 04:59:56 +0000 | [diff] [blame] | 2017 | // Check to see if we can DIE the instruction... |
| 2018 | if (isInstructionTriviallyDead(I)) { |
| 2019 | // Add operands to the worklist... |
Chris Lattner | 4bb7c02 | 2003-10-06 17:11:01 +0000 | [diff] [blame] | 2020 | if (I->getNumOperands() < 4) |
| 2021 | for (unsigned i = 0, e = I->getNumOperands(); i != e; ++i) |
| 2022 | if (Instruction *Op = dyn_cast<Instruction>(I->getOperand(i))) |
| 2023 | WorkList.push_back(Op); |
Chris Lattner | 62b14df | 2002-09-02 04:59:56 +0000 | [diff] [blame] | 2024 | ++NumDeadInst; |
Chris Lattner | 4bb7c02 | 2003-10-06 17:11:01 +0000 | [diff] [blame] | 2025 | |
| 2026 | I->getParent()->getInstList().erase(I); |
| 2027 | removeFromWorkList(I); |
| 2028 | continue; |
| 2029 | } |
Chris Lattner | 62b14df | 2002-09-02 04:59:56 +0000 | [diff] [blame] | 2030 | |
Misha Brukman | a3bbcb5 | 2002-10-29 23:06:16 +0000 | [diff] [blame] | 2031 | // Instruction isn't dead, see if we can constant propagate it... |
Chris Lattner | 62b14df | 2002-09-02 04:59:56 +0000 | [diff] [blame] | 2032 | if (Constant *C = ConstantFoldInstruction(I)) { |
| 2033 | // Add operands to the worklist... |
| 2034 | for (unsigned i = 0, e = I->getNumOperands(); i != e; ++i) |
| 2035 | if (Instruction *Op = dyn_cast<Instruction>(I->getOperand(i))) |
| 2036 | WorkList.push_back(Op); |
Chris Lattner | c736d56 | 2002-12-05 22:41:53 +0000 | [diff] [blame] | 2037 | ReplaceInstUsesWith(*I, C); |
| 2038 | |
Chris Lattner | 62b14df | 2002-09-02 04:59:56 +0000 | [diff] [blame] | 2039 | ++NumConstProp; |
Chris Lattner | 4bb7c02 | 2003-10-06 17:11:01 +0000 | [diff] [blame] | 2040 | I->getParent()->getInstList().erase(I); |
Chris Lattner | 6061000 | 2003-10-07 15:17:02 +0000 | [diff] [blame] | 2041 | removeFromWorkList(I); |
Chris Lattner | 4bb7c02 | 2003-10-06 17:11:01 +0000 | [diff] [blame] | 2042 | continue; |
Chris Lattner | 62b14df | 2002-09-02 04:59:56 +0000 | [diff] [blame] | 2043 | } |
Chris Lattner | 4bb7c02 | 2003-10-06 17:11:01 +0000 | [diff] [blame] | 2044 | |
Chris Lattner | 8a2a311 | 2001-12-14 16:52:21 +0000 | [diff] [blame] | 2045 | // Now that we have an instruction, try combining it to simplify it... |
Chris Lattner | 90ac28c | 2002-08-02 19:29:35 +0000 | [diff] [blame] | 2046 | if (Instruction *Result = visit(*I)) { |
Chris Lattner | 3dec1f2 | 2002-05-10 15:38:35 +0000 | [diff] [blame] | 2047 | ++NumCombined; |
Chris Lattner | dd841ae | 2002-04-18 17:39:14 +0000 | [diff] [blame] | 2048 | // Should we replace the old instruction with a new one? |
Chris Lattner | b3bc8fa | 2002-05-14 15:24:07 +0000 | [diff] [blame] | 2049 | if (Result != I) { |
| 2050 | // Instructions can end up on the worklist more than once. Make sure |
| 2051 | // we do not process an instruction that has been deleted. |
Chris Lattner | 62b14df | 2002-09-02 04:59:56 +0000 | [diff] [blame] | 2052 | removeFromWorkList(I); |
Chris Lattner | 4bb7c02 | 2003-10-06 17:11:01 +0000 | [diff] [blame] | 2053 | |
| 2054 | // Move the name to the new instruction first... |
| 2055 | std::string OldName = I->getName(); I->setName(""); |
Chris Lattner | d558dc3 | 2003-10-07 22:58:41 +0000 | [diff] [blame] | 2056 | Result->setName(OldName); |
Chris Lattner | 4bb7c02 | 2003-10-06 17:11:01 +0000 | [diff] [blame] | 2057 | |
| 2058 | // Insert the new instruction into the basic block... |
| 2059 | BasicBlock *InstParent = I->getParent(); |
| 2060 | InstParent->getInstList().insert(I, Result); |
| 2061 | |
| 2062 | // Everything uses the new instruction now... |
| 2063 | I->replaceAllUsesWith(Result); |
| 2064 | |
| 2065 | // Erase the old instruction. |
| 2066 | InstParent->getInstList().erase(I); |
Chris Lattner | 7e70829 | 2002-06-25 16:13:24 +0000 | [diff] [blame] | 2067 | } else { |
Chris Lattner | 90ac28c | 2002-08-02 19:29:35 +0000 | [diff] [blame] | 2068 | BasicBlock::iterator II = I; |
| 2069 | |
| 2070 | // If the instruction was modified, it's possible that it is now dead. |
| 2071 | // if so, remove it. |
| 2072 | if (dceInstruction(II)) { |
| 2073 | // Instructions may end up in the worklist more than once. Erase them |
| 2074 | // all. |
Chris Lattner | 62b14df | 2002-09-02 04:59:56 +0000 | [diff] [blame] | 2075 | removeFromWorkList(I); |
Chris Lattner | 90ac28c | 2002-08-02 19:29:35 +0000 | [diff] [blame] | 2076 | Result = 0; |
| 2077 | } |
Chris Lattner | b3bc8fa | 2002-05-14 15:24:07 +0000 | [diff] [blame] | 2078 | } |
Chris Lattner | dd841ae | 2002-04-18 17:39:14 +0000 | [diff] [blame] | 2079 | |
Chris Lattner | 90ac28c | 2002-08-02 19:29:35 +0000 | [diff] [blame] | 2080 | if (Result) { |
| 2081 | WorkList.push_back(Result); |
| 2082 | AddUsesToWorkList(*Result); |
| 2083 | } |
Chris Lattner | dd841ae | 2002-04-18 17:39:14 +0000 | [diff] [blame] | 2084 | Changed = true; |
Chris Lattner | 8a2a311 | 2001-12-14 16:52:21 +0000 | [diff] [blame] | 2085 | } |
| 2086 | } |
| 2087 | |
Chris Lattner | dd841ae | 2002-04-18 17:39:14 +0000 | [diff] [blame] | 2088 | return Changed; |
Chris Lattner | bd0ef77 | 2002-02-26 21:46:54 +0000 | [diff] [blame] | 2089 | } |
| 2090 | |
| 2091 | Pass *createInstructionCombiningPass() { |
Chris Lattner | dd841ae | 2002-04-18 17:39:14 +0000 | [diff] [blame] | 2092 | return new InstCombiner(); |
Chris Lattner | bd0ef77 | 2002-02-26 21:46:54 +0000 | [diff] [blame] | 2093 | } |