Chris Lattner | 7e04491 | 2010-01-04 07:17:19 +0000 | [diff] [blame] | 1 | //===- InstCombineSimplifyDemanded.cpp ------------------------------------===// |
| 2 | // |
| 3 | // The LLVM Compiler Infrastructure |
| 4 | // |
| 5 | // This file is distributed under the University of Illinois Open Source |
| 6 | // License. See LICENSE.TXT for details. |
| 7 | // |
| 8 | //===----------------------------------------------------------------------===// |
| 9 | // |
| 10 | // This file contains logic for simplifying instructions based on information |
| 11 | // about how they are used. |
| 12 | // |
| 13 | //===----------------------------------------------------------------------===// |
| 14 | |
Chandler Carruth | a917458 | 2015-01-22 05:25:13 +0000 | [diff] [blame] | 15 | #include "InstCombineInternal.h" |
Chandler Carruth | 9fb823b | 2013-01-02 11:36:10 +0000 | [diff] [blame] | 16 | #include "llvm/IR/DataLayout.h" |
| 17 | #include "llvm/IR/IntrinsicInst.h" |
Chandler Carruth | 820a908 | 2014-03-04 11:08:18 +0000 | [diff] [blame] | 18 | #include "llvm/IR/PatternMatch.h" |
Chris Lattner | 7e04491 | 2010-01-04 07:17:19 +0000 | [diff] [blame] | 19 | |
| 20 | using namespace llvm; |
Shuxin Yang | 63e999e | 2012-12-04 00:04:54 +0000 | [diff] [blame] | 21 | using namespace llvm::PatternMatch; |
Chris Lattner | 7e04491 | 2010-01-04 07:17:19 +0000 | [diff] [blame] | 22 | |
Chandler Carruth | 964daaa | 2014-04-22 02:55:47 +0000 | [diff] [blame] | 23 | #define DEBUG_TYPE "instcombine" |
| 24 | |
Craig Topper | 4c94775 | 2012-12-22 18:09:02 +0000 | [diff] [blame] | 25 | /// ShrinkDemandedConstant - Check to see if the specified operand of the |
Chris Lattner | 7e04491 | 2010-01-04 07:17:19 +0000 | [diff] [blame] | 26 | /// specified instruction is a constant integer. If so, check to see if there |
| 27 | /// are any bits set in the constant that are not demanded. If so, shrink the |
| 28 | /// constant and return true. |
Craig Topper | 4c94775 | 2012-12-22 18:09:02 +0000 | [diff] [blame] | 29 | static bool ShrinkDemandedConstant(Instruction *I, unsigned OpNo, |
Chris Lattner | 7e04491 | 2010-01-04 07:17:19 +0000 | [diff] [blame] | 30 | APInt Demanded) { |
| 31 | assert(I && "No instruction?"); |
| 32 | assert(OpNo < I->getNumOperands() && "Operand index too large"); |
| 33 | |
| 34 | // If the operand is not a constant integer, nothing to do. |
| 35 | ConstantInt *OpC = dyn_cast<ConstantInt>(I->getOperand(OpNo)); |
| 36 | if (!OpC) return false; |
| 37 | |
| 38 | // If there are no bits set that aren't demanded, nothing to do. |
Jay Foad | 583abbc | 2010-12-07 08:25:19 +0000 | [diff] [blame] | 39 | Demanded = Demanded.zextOrTrunc(OpC->getValue().getBitWidth()); |
Chris Lattner | 7e04491 | 2010-01-04 07:17:19 +0000 | [diff] [blame] | 40 | if ((~Demanded & OpC->getValue()) == 0) |
| 41 | return false; |
| 42 | |
| 43 | // This instruction is producing bits that are not demanded. Shrink the RHS. |
| 44 | Demanded &= OpC->getValue(); |
| 45 | I->setOperand(OpNo, ConstantInt::get(OpC->getType(), Demanded)); |
David Majnemer | 42b83a5 | 2014-08-22 07:56:32 +0000 | [diff] [blame] | 46 | |
David Majnemer | 49775e0 | 2014-08-22 17:11:04 +0000 | [diff] [blame] | 47 | // If either 'nsw' or 'nuw' is set and the constant is negative, |
| 48 | // removing *any* bits from the constant could make overflow occur. |
| 49 | // Remove 'nsw' and 'nuw' from the instruction in this case. |
| 50 | if (auto *OBO = dyn_cast<OverflowingBinaryOperator>(I)) { |
| 51 | assert(OBO->getOpcode() == Instruction::Add); |
| 52 | if (OBO->hasNoSignedWrap() || OBO->hasNoUnsignedWrap()) { |
| 53 | if (OpC->getValue().isNegative()) { |
| 54 | cast<BinaryOperator>(OBO)->setHasNoSignedWrap(false); |
| 55 | cast<BinaryOperator>(OBO)->setHasNoUnsignedWrap(false); |
| 56 | } |
| 57 | } |
| 58 | } |
David Majnemer | 42b83a5 | 2014-08-22 07:56:32 +0000 | [diff] [blame] | 59 | |
Chris Lattner | 7e04491 | 2010-01-04 07:17:19 +0000 | [diff] [blame] | 60 | return true; |
| 61 | } |
| 62 | |
| 63 | |
| 64 | |
| 65 | /// SimplifyDemandedInstructionBits - Inst is an integer instruction that |
| 66 | /// SimplifyDemandedBits knows about. See if the instruction has any |
| 67 | /// properties that allow us to simplify its operands. |
| 68 | bool InstCombiner::SimplifyDemandedInstructionBits(Instruction &Inst) { |
| 69 | unsigned BitWidth = Inst.getType()->getScalarSizeInBits(); |
| 70 | APInt KnownZero(BitWidth, 0), KnownOne(BitWidth, 0); |
| 71 | APInt DemandedMask(APInt::getAllOnesValue(BitWidth)); |
Craig Topper | 4c94775 | 2012-12-22 18:09:02 +0000 | [diff] [blame] | 72 | |
| 73 | Value *V = SimplifyDemandedUseBits(&Inst, DemandedMask, |
Hal Finkel | 60db058 | 2014-09-07 18:57:58 +0000 | [diff] [blame] | 74 | KnownZero, KnownOne, 0, &Inst); |
Craig Topper | f40110f | 2014-04-25 05:29:35 +0000 | [diff] [blame] | 75 | if (!V) return false; |
Chris Lattner | 7e04491 | 2010-01-04 07:17:19 +0000 | [diff] [blame] | 76 | if (V == &Inst) return true; |
| 77 | ReplaceInstUsesWith(Inst, V); |
| 78 | return true; |
| 79 | } |
| 80 | |
| 81 | /// SimplifyDemandedBits - This form of SimplifyDemandedBits simplifies the |
| 82 | /// specified instruction operand if possible, updating it in place. It returns |
| 83 | /// true if it made any change and false otherwise. |
Craig Topper | 4c94775 | 2012-12-22 18:09:02 +0000 | [diff] [blame] | 84 | bool InstCombiner::SimplifyDemandedBits(Use &U, APInt DemandedMask, |
Chris Lattner | 7e04491 | 2010-01-04 07:17:19 +0000 | [diff] [blame] | 85 | APInt &KnownZero, APInt &KnownOne, |
| 86 | unsigned Depth) { |
| 87 | Value *NewVal = SimplifyDemandedUseBits(U.get(), DemandedMask, |
Hal Finkel | 60db058 | 2014-09-07 18:57:58 +0000 | [diff] [blame] | 88 | KnownZero, KnownOne, Depth, |
| 89 | dyn_cast<Instruction>(U.getUser())); |
Craig Topper | f40110f | 2014-04-25 05:29:35 +0000 | [diff] [blame] | 90 | if (!NewVal) return false; |
Chris Lattner | 7e04491 | 2010-01-04 07:17:19 +0000 | [diff] [blame] | 91 | U = NewVal; |
| 92 | return true; |
| 93 | } |
| 94 | |
| 95 | |
| 96 | /// SimplifyDemandedUseBits - This function attempts to replace V with a simpler |
| 97 | /// value based on the demanded bits. When this function is called, it is known |
| 98 | /// that only the bits set in DemandedMask of the result of V are ever used |
| 99 | /// downstream. Consequently, depending on the mask and V, it may be possible |
| 100 | /// to replace V with a constant or one of its operands. In such cases, this |
| 101 | /// function does the replacement and returns true. In all other cases, it |
| 102 | /// returns false after analyzing the expression and setting KnownOne and known |
| 103 | /// to be one in the expression. KnownZero contains all the bits that are known |
| 104 | /// to be zero in the expression. These are provided to potentially allow the |
| 105 | /// caller (which might recursively be SimplifyDemandedBits itself) to simplify |
Craig Topper | 4c94775 | 2012-12-22 18:09:02 +0000 | [diff] [blame] | 106 | /// the expression. KnownOne and KnownZero always follow the invariant that |
Chris Lattner | 7e04491 | 2010-01-04 07:17:19 +0000 | [diff] [blame] | 107 | /// KnownOne & KnownZero == 0. That is, a bit can't be both 1 and 0. Note that |
| 108 | /// the bits in KnownOne and KnownZero may only be accurate for those bits set |
| 109 | /// in DemandedMask. Note also that the bitwidth of V, DemandedMask, KnownZero |
| 110 | /// and KnownOne must all be the same. |
| 111 | /// |
| 112 | /// This returns null if it did not change anything and it permits no |
| 113 | /// simplification. This returns V itself if it did some simplification of V's |
| 114 | /// operands based on the information about what bits are demanded. This returns |
| 115 | /// some other non-null value if it found out that V is equal to another value |
| 116 | /// in the context where the specified bits are demanded, but not for all users. |
| 117 | Value *InstCombiner::SimplifyDemandedUseBits(Value *V, APInt DemandedMask, |
| 118 | APInt &KnownZero, APInt &KnownOne, |
Hal Finkel | 60db058 | 2014-09-07 18:57:58 +0000 | [diff] [blame] | 119 | unsigned Depth, |
| 120 | Instruction *CxtI) { |
Craig Topper | e73658d | 2014-04-28 04:05:08 +0000 | [diff] [blame] | 121 | assert(V != nullptr && "Null pointer of Value???"); |
Chris Lattner | 7e04491 | 2010-01-04 07:17:19 +0000 | [diff] [blame] | 122 | assert(Depth <= 6 && "Limit Search Depth"); |
| 123 | uint32_t BitWidth = DemandedMask.getBitWidth(); |
Chris Lattner | 229907c | 2011-07-18 04:54:35 +0000 | [diff] [blame] | 124 | Type *VTy = V->getType(); |
Rafael Espindola | 37dc9e1 | 2014-02-21 00:06:31 +0000 | [diff] [blame] | 125 | assert((DL || !VTy->isPointerTy()) && |
Chris Lattner | 7e04491 | 2010-01-04 07:17:19 +0000 | [diff] [blame] | 126 | "SimplifyDemandedBits needs to know bit widths!"); |
Rafael Espindola | 37dc9e1 | 2014-02-21 00:06:31 +0000 | [diff] [blame] | 127 | assert((!DL || DL->getTypeSizeInBits(VTy->getScalarType()) == BitWidth) && |
Duncan Sands | 9dff9be | 2010-02-15 16:12:20 +0000 | [diff] [blame] | 128 | (!VTy->isIntOrIntVectorTy() || |
Chris Lattner | 7e04491 | 2010-01-04 07:17:19 +0000 | [diff] [blame] | 129 | VTy->getScalarSizeInBits() == BitWidth) && |
| 130 | KnownZero.getBitWidth() == BitWidth && |
| 131 | KnownOne.getBitWidth() == BitWidth && |
| 132 | "Value *V, DemandedMask, KnownZero and KnownOne " |
| 133 | "must have same BitWidth"); |
| 134 | if (ConstantInt *CI = dyn_cast<ConstantInt>(V)) { |
| 135 | // We know all of the bits for a constant! |
| 136 | KnownOne = CI->getValue() & DemandedMask; |
| 137 | KnownZero = ~KnownOne & DemandedMask; |
Craig Topper | f40110f | 2014-04-25 05:29:35 +0000 | [diff] [blame] | 138 | return nullptr; |
Chris Lattner | 7e04491 | 2010-01-04 07:17:19 +0000 | [diff] [blame] | 139 | } |
| 140 | if (isa<ConstantPointerNull>(V)) { |
| 141 | // We know all of the bits for a constant! |
Jay Foad | 25a5e4c | 2010-12-01 08:53:58 +0000 | [diff] [blame] | 142 | KnownOne.clearAllBits(); |
Chris Lattner | 7e04491 | 2010-01-04 07:17:19 +0000 | [diff] [blame] | 143 | KnownZero = DemandedMask; |
Craig Topper | f40110f | 2014-04-25 05:29:35 +0000 | [diff] [blame] | 144 | return nullptr; |
Chris Lattner | 7e04491 | 2010-01-04 07:17:19 +0000 | [diff] [blame] | 145 | } |
| 146 | |
Jay Foad | 25a5e4c | 2010-12-01 08:53:58 +0000 | [diff] [blame] | 147 | KnownZero.clearAllBits(); |
| 148 | KnownOne.clearAllBits(); |
Chris Lattner | 7e04491 | 2010-01-04 07:17:19 +0000 | [diff] [blame] | 149 | if (DemandedMask == 0) { // Not demanding any bits from V. |
| 150 | if (isa<UndefValue>(V)) |
Craig Topper | f40110f | 2014-04-25 05:29:35 +0000 | [diff] [blame] | 151 | return nullptr; |
Chris Lattner | 7e04491 | 2010-01-04 07:17:19 +0000 | [diff] [blame] | 152 | return UndefValue::get(VTy); |
| 153 | } |
Craig Topper | 4c94775 | 2012-12-22 18:09:02 +0000 | [diff] [blame] | 154 | |
Chris Lattner | 7e04491 | 2010-01-04 07:17:19 +0000 | [diff] [blame] | 155 | if (Depth == 6) // Limit search depth. |
Craig Topper | f40110f | 2014-04-25 05:29:35 +0000 | [diff] [blame] | 156 | return nullptr; |
Craig Topper | 4c94775 | 2012-12-22 18:09:02 +0000 | [diff] [blame] | 157 | |
Chris Lattner | 7e04491 | 2010-01-04 07:17:19 +0000 | [diff] [blame] | 158 | APInt LHSKnownZero(BitWidth, 0), LHSKnownOne(BitWidth, 0); |
Duncan Sands | c8a3e56 | 2010-01-29 06:18:46 +0000 | [diff] [blame] | 159 | APInt RHSKnownZero(BitWidth, 0), RHSKnownOne(BitWidth, 0); |
Chris Lattner | 7e04491 | 2010-01-04 07:17:19 +0000 | [diff] [blame] | 160 | |
| 161 | Instruction *I = dyn_cast<Instruction>(V); |
| 162 | if (!I) { |
Hal Finkel | 60db058 | 2014-09-07 18:57:58 +0000 | [diff] [blame] | 163 | computeKnownBits(V, KnownZero, KnownOne, Depth, CxtI); |
Craig Topper | f40110f | 2014-04-25 05:29:35 +0000 | [diff] [blame] | 164 | return nullptr; // Only analyze instructions. |
Chris Lattner | 7e04491 | 2010-01-04 07:17:19 +0000 | [diff] [blame] | 165 | } |
| 166 | |
| 167 | // If there are multiple uses of this value and we aren't at the root, then |
| 168 | // we can't do any simplifications of the operands, because DemandedMask |
| 169 | // only reflects the bits demanded by *one* of the users. |
| 170 | if (Depth != 0 && !I->hasOneUse()) { |
| 171 | // Despite the fact that we can't simplify this instruction in all User's |
| 172 | // context, we can at least compute the knownzero/knownone bits, and we can |
| 173 | // do simplifications that apply to *just* the one user if we know that |
| 174 | // this instruction has a simpler value in that context. |
| 175 | if (I->getOpcode() == Instruction::And) { |
| 176 | // If either the LHS or the RHS are Zero, the result is zero. |
Hal Finkel | 60db058 | 2014-09-07 18:57:58 +0000 | [diff] [blame] | 177 | computeKnownBits(I->getOperand(1), RHSKnownZero, RHSKnownOne, Depth+1, |
| 178 | CxtI); |
| 179 | computeKnownBits(I->getOperand(0), LHSKnownZero, LHSKnownOne, Depth+1, |
| 180 | CxtI); |
Craig Topper | 4c94775 | 2012-12-22 18:09:02 +0000 | [diff] [blame] | 181 | |
Chris Lattner | 7e04491 | 2010-01-04 07:17:19 +0000 | [diff] [blame] | 182 | // If all of the demanded bits are known 1 on one side, return the other. |
| 183 | // These bits cannot contribute to the result of the 'and' in this |
| 184 | // context. |
Craig Topper | 4c94775 | 2012-12-22 18:09:02 +0000 | [diff] [blame] | 185 | if ((DemandedMask & ~LHSKnownZero & RHSKnownOne) == |
Chris Lattner | 7e04491 | 2010-01-04 07:17:19 +0000 | [diff] [blame] | 186 | (DemandedMask & ~LHSKnownZero)) |
| 187 | return I->getOperand(0); |
Craig Topper | 4c94775 | 2012-12-22 18:09:02 +0000 | [diff] [blame] | 188 | if ((DemandedMask & ~RHSKnownZero & LHSKnownOne) == |
Chris Lattner | 7e04491 | 2010-01-04 07:17:19 +0000 | [diff] [blame] | 189 | (DemandedMask & ~RHSKnownZero)) |
| 190 | return I->getOperand(1); |
Craig Topper | 4c94775 | 2012-12-22 18:09:02 +0000 | [diff] [blame] | 191 | |
Chris Lattner | 7e04491 | 2010-01-04 07:17:19 +0000 | [diff] [blame] | 192 | // If all of the demanded bits in the inputs are known zeros, return zero. |
| 193 | if ((DemandedMask & (RHSKnownZero|LHSKnownZero)) == DemandedMask) |
| 194 | return Constant::getNullValue(VTy); |
Craig Topper | 4c94775 | 2012-12-22 18:09:02 +0000 | [diff] [blame] | 195 | |
Chris Lattner | 7e04491 | 2010-01-04 07:17:19 +0000 | [diff] [blame] | 196 | } else if (I->getOpcode() == Instruction::Or) { |
| 197 | // We can simplify (X|Y) -> X or Y in the user's context if we know that |
| 198 | // only bits from X or Y are demanded. |
Craig Topper | 4c94775 | 2012-12-22 18:09:02 +0000 | [diff] [blame] | 199 | |
Chris Lattner | 7e04491 | 2010-01-04 07:17:19 +0000 | [diff] [blame] | 200 | // If either the LHS or the RHS are One, the result is One. |
Hal Finkel | 60db058 | 2014-09-07 18:57:58 +0000 | [diff] [blame] | 201 | computeKnownBits(I->getOperand(1), RHSKnownZero, RHSKnownOne, Depth+1, |
| 202 | CxtI); |
| 203 | computeKnownBits(I->getOperand(0), LHSKnownZero, LHSKnownOne, Depth+1, |
| 204 | CxtI); |
Craig Topper | 4c94775 | 2012-12-22 18:09:02 +0000 | [diff] [blame] | 205 | |
Chris Lattner | 7e04491 | 2010-01-04 07:17:19 +0000 | [diff] [blame] | 206 | // If all of the demanded bits are known zero on one side, return the |
| 207 | // other. These bits cannot contribute to the result of the 'or' in this |
| 208 | // context. |
Craig Topper | 4c94775 | 2012-12-22 18:09:02 +0000 | [diff] [blame] | 209 | if ((DemandedMask & ~LHSKnownOne & RHSKnownZero) == |
Chris Lattner | 7e04491 | 2010-01-04 07:17:19 +0000 | [diff] [blame] | 210 | (DemandedMask & ~LHSKnownOne)) |
| 211 | return I->getOperand(0); |
Craig Topper | 4c94775 | 2012-12-22 18:09:02 +0000 | [diff] [blame] | 212 | if ((DemandedMask & ~RHSKnownOne & LHSKnownZero) == |
Chris Lattner | 7e04491 | 2010-01-04 07:17:19 +0000 | [diff] [blame] | 213 | (DemandedMask & ~RHSKnownOne)) |
| 214 | return I->getOperand(1); |
Craig Topper | 4c94775 | 2012-12-22 18:09:02 +0000 | [diff] [blame] | 215 | |
Chris Lattner | 7e04491 | 2010-01-04 07:17:19 +0000 | [diff] [blame] | 216 | // If all of the potentially set bits on one side are known to be set on |
| 217 | // the other side, just use the 'other' side. |
Craig Topper | 4c94775 | 2012-12-22 18:09:02 +0000 | [diff] [blame] | 218 | if ((DemandedMask & (~RHSKnownZero) & LHSKnownOne) == |
Chris Lattner | 7e04491 | 2010-01-04 07:17:19 +0000 | [diff] [blame] | 219 | (DemandedMask & (~RHSKnownZero))) |
| 220 | return I->getOperand(0); |
Craig Topper | 4c94775 | 2012-12-22 18:09:02 +0000 | [diff] [blame] | 221 | if ((DemandedMask & (~LHSKnownZero) & RHSKnownOne) == |
Chris Lattner | 7e04491 | 2010-01-04 07:17:19 +0000 | [diff] [blame] | 222 | (DemandedMask & (~LHSKnownZero))) |
| 223 | return I->getOperand(1); |
Shuxin Yang | 7328593 | 2012-12-04 22:15:32 +0000 | [diff] [blame] | 224 | } else if (I->getOpcode() == Instruction::Xor) { |
| 225 | // We can simplify (X^Y) -> X or Y in the user's context if we know that |
| 226 | // only bits from X or Y are demanded. |
Craig Topper | 4c94775 | 2012-12-22 18:09:02 +0000 | [diff] [blame] | 227 | |
Hal Finkel | 60db058 | 2014-09-07 18:57:58 +0000 | [diff] [blame] | 228 | computeKnownBits(I->getOperand(1), RHSKnownZero, RHSKnownOne, Depth+1, |
| 229 | CxtI); |
| 230 | computeKnownBits(I->getOperand(0), LHSKnownZero, LHSKnownOne, Depth+1, |
| 231 | CxtI); |
Craig Topper | 4c94775 | 2012-12-22 18:09:02 +0000 | [diff] [blame] | 232 | |
Shuxin Yang | 7328593 | 2012-12-04 22:15:32 +0000 | [diff] [blame] | 233 | // If all of the demanded bits are known zero on one side, return the |
Craig Topper | 4c94775 | 2012-12-22 18:09:02 +0000 | [diff] [blame] | 234 | // other. |
Shuxin Yang | 7328593 | 2012-12-04 22:15:32 +0000 | [diff] [blame] | 235 | if ((DemandedMask & RHSKnownZero) == DemandedMask) |
| 236 | return I->getOperand(0); |
| 237 | if ((DemandedMask & LHSKnownZero) == DemandedMask) |
| 238 | return I->getOperand(1); |
Chris Lattner | 7e04491 | 2010-01-04 07:17:19 +0000 | [diff] [blame] | 239 | } |
Shuxin Yang | 7328593 | 2012-12-04 22:15:32 +0000 | [diff] [blame] | 240 | |
Chris Lattner | 7e04491 | 2010-01-04 07:17:19 +0000 | [diff] [blame] | 241 | // Compute the KnownZero/KnownOne bits to simplify things downstream. |
Hal Finkel | 60db058 | 2014-09-07 18:57:58 +0000 | [diff] [blame] | 242 | computeKnownBits(I, KnownZero, KnownOne, Depth, CxtI); |
Craig Topper | f40110f | 2014-04-25 05:29:35 +0000 | [diff] [blame] | 243 | return nullptr; |
Chris Lattner | 7e04491 | 2010-01-04 07:17:19 +0000 | [diff] [blame] | 244 | } |
Craig Topper | 4c94775 | 2012-12-22 18:09:02 +0000 | [diff] [blame] | 245 | |
Chris Lattner | 7e04491 | 2010-01-04 07:17:19 +0000 | [diff] [blame] | 246 | // If this is the root being simplified, allow it to have multiple uses, |
| 247 | // just set the DemandedMask to all bits so that we can try to simplify the |
| 248 | // operands. This allows visitTruncInst (for example) to simplify the |
| 249 | // operand of a trunc without duplicating all the logic below. |
| 250 | if (Depth == 0 && !V->hasOneUse()) |
| 251 | DemandedMask = APInt::getAllOnesValue(BitWidth); |
Craig Topper | 4c94775 | 2012-12-22 18:09:02 +0000 | [diff] [blame] | 252 | |
Chris Lattner | 7e04491 | 2010-01-04 07:17:19 +0000 | [diff] [blame] | 253 | switch (I->getOpcode()) { |
| 254 | default: |
Hal Finkel | 60db058 | 2014-09-07 18:57:58 +0000 | [diff] [blame] | 255 | computeKnownBits(I, KnownZero, KnownOne, Depth, CxtI); |
Chris Lattner | 7e04491 | 2010-01-04 07:17:19 +0000 | [diff] [blame] | 256 | break; |
| 257 | case Instruction::And: |
| 258 | // If either the LHS or the RHS are Zero, the result is zero. |
| 259 | if (SimplifyDemandedBits(I->getOperandUse(1), DemandedMask, |
| 260 | RHSKnownZero, RHSKnownOne, Depth+1) || |
| 261 | SimplifyDemandedBits(I->getOperandUse(0), DemandedMask & ~RHSKnownZero, |
| 262 | LHSKnownZero, LHSKnownOne, Depth+1)) |
| 263 | return I; |
Craig Topper | 4c94775 | 2012-12-22 18:09:02 +0000 | [diff] [blame] | 264 | assert(!(RHSKnownZero & RHSKnownOne) && "Bits known to be one AND zero?"); |
| 265 | assert(!(LHSKnownZero & LHSKnownOne) && "Bits known to be one AND zero?"); |
Chris Lattner | 7e04491 | 2010-01-04 07:17:19 +0000 | [diff] [blame] | 266 | |
Hal Finkel | 15aeaaf | 2014-09-07 19:21:07 +0000 | [diff] [blame] | 267 | // If the client is only demanding bits that we know, return the known |
| 268 | // constant. |
| 269 | if ((DemandedMask & ((RHSKnownZero | LHSKnownZero)| |
| 270 | (RHSKnownOne & LHSKnownOne))) == DemandedMask) |
| 271 | return Constant::getIntegerValue(VTy, RHSKnownOne & LHSKnownOne); |
| 272 | |
Chris Lattner | 7e04491 | 2010-01-04 07:17:19 +0000 | [diff] [blame] | 273 | // If all of the demanded bits are known 1 on one side, return the other. |
| 274 | // These bits cannot contribute to the result of the 'and'. |
Craig Topper | 4c94775 | 2012-12-22 18:09:02 +0000 | [diff] [blame] | 275 | if ((DemandedMask & ~LHSKnownZero & RHSKnownOne) == |
Chris Lattner | 7e04491 | 2010-01-04 07:17:19 +0000 | [diff] [blame] | 276 | (DemandedMask & ~LHSKnownZero)) |
| 277 | return I->getOperand(0); |
Craig Topper | 4c94775 | 2012-12-22 18:09:02 +0000 | [diff] [blame] | 278 | if ((DemandedMask & ~RHSKnownZero & LHSKnownOne) == |
Chris Lattner | 7e04491 | 2010-01-04 07:17:19 +0000 | [diff] [blame] | 279 | (DemandedMask & ~RHSKnownZero)) |
| 280 | return I->getOperand(1); |
Craig Topper | 4c94775 | 2012-12-22 18:09:02 +0000 | [diff] [blame] | 281 | |
Chris Lattner | 7e04491 | 2010-01-04 07:17:19 +0000 | [diff] [blame] | 282 | // If all of the demanded bits in the inputs are known zeros, return zero. |
| 283 | if ((DemandedMask & (RHSKnownZero|LHSKnownZero)) == DemandedMask) |
| 284 | return Constant::getNullValue(VTy); |
Craig Topper | 4c94775 | 2012-12-22 18:09:02 +0000 | [diff] [blame] | 285 | |
Chris Lattner | 7e04491 | 2010-01-04 07:17:19 +0000 | [diff] [blame] | 286 | // If the RHS is a constant, see if we can simplify it. |
| 287 | if (ShrinkDemandedConstant(I, 1, DemandedMask & ~LHSKnownZero)) |
| 288 | return I; |
Craig Topper | 4c94775 | 2012-12-22 18:09:02 +0000 | [diff] [blame] | 289 | |
Chris Lattner | 7e04491 | 2010-01-04 07:17:19 +0000 | [diff] [blame] | 290 | // Output known-1 bits are only known if set in both the LHS & RHS. |
Duncan Sands | c8a3e56 | 2010-01-29 06:18:46 +0000 | [diff] [blame] | 291 | KnownOne = RHSKnownOne & LHSKnownOne; |
Chris Lattner | 7e04491 | 2010-01-04 07:17:19 +0000 | [diff] [blame] | 292 | // Output known-0 are known to be clear if zero in either the LHS | RHS. |
Duncan Sands | c8a3e56 | 2010-01-29 06:18:46 +0000 | [diff] [blame] | 293 | KnownZero = RHSKnownZero | LHSKnownZero; |
Chris Lattner | 7e04491 | 2010-01-04 07:17:19 +0000 | [diff] [blame] | 294 | break; |
| 295 | case Instruction::Or: |
| 296 | // If either the LHS or the RHS are One, the result is One. |
Craig Topper | 4c94775 | 2012-12-22 18:09:02 +0000 | [diff] [blame] | 297 | if (SimplifyDemandedBits(I->getOperandUse(1), DemandedMask, |
Chris Lattner | 7e04491 | 2010-01-04 07:17:19 +0000 | [diff] [blame] | 298 | RHSKnownZero, RHSKnownOne, Depth+1) || |
Craig Topper | 4c94775 | 2012-12-22 18:09:02 +0000 | [diff] [blame] | 299 | SimplifyDemandedBits(I->getOperandUse(0), DemandedMask & ~RHSKnownOne, |
Chris Lattner | 7e04491 | 2010-01-04 07:17:19 +0000 | [diff] [blame] | 300 | LHSKnownZero, LHSKnownOne, Depth+1)) |
| 301 | return I; |
Craig Topper | 4c94775 | 2012-12-22 18:09:02 +0000 | [diff] [blame] | 302 | assert(!(RHSKnownZero & RHSKnownOne) && "Bits known to be one AND zero?"); |
| 303 | assert(!(LHSKnownZero & LHSKnownOne) && "Bits known to be one AND zero?"); |
| 304 | |
Hal Finkel | 15aeaaf | 2014-09-07 19:21:07 +0000 | [diff] [blame] | 305 | // If the client is only demanding bits that we know, return the known |
| 306 | // constant. |
| 307 | if ((DemandedMask & ((RHSKnownZero & LHSKnownZero)| |
| 308 | (RHSKnownOne | LHSKnownOne))) == DemandedMask) |
| 309 | return Constant::getIntegerValue(VTy, RHSKnownOne | LHSKnownOne); |
| 310 | |
Chris Lattner | 7e04491 | 2010-01-04 07:17:19 +0000 | [diff] [blame] | 311 | // If all of the demanded bits are known zero on one side, return the other. |
| 312 | // These bits cannot contribute to the result of the 'or'. |
Craig Topper | 4c94775 | 2012-12-22 18:09:02 +0000 | [diff] [blame] | 313 | if ((DemandedMask & ~LHSKnownOne & RHSKnownZero) == |
Chris Lattner | 7e04491 | 2010-01-04 07:17:19 +0000 | [diff] [blame] | 314 | (DemandedMask & ~LHSKnownOne)) |
| 315 | return I->getOperand(0); |
Craig Topper | 4c94775 | 2012-12-22 18:09:02 +0000 | [diff] [blame] | 316 | if ((DemandedMask & ~RHSKnownOne & LHSKnownZero) == |
Chris Lattner | 7e04491 | 2010-01-04 07:17:19 +0000 | [diff] [blame] | 317 | (DemandedMask & ~RHSKnownOne)) |
| 318 | return I->getOperand(1); |
| 319 | |
| 320 | // If all of the potentially set bits on one side are known to be set on |
| 321 | // the other side, just use the 'other' side. |
Craig Topper | 4c94775 | 2012-12-22 18:09:02 +0000 | [diff] [blame] | 322 | if ((DemandedMask & (~RHSKnownZero) & LHSKnownOne) == |
Chris Lattner | 7e04491 | 2010-01-04 07:17:19 +0000 | [diff] [blame] | 323 | (DemandedMask & (~RHSKnownZero))) |
| 324 | return I->getOperand(0); |
Craig Topper | 4c94775 | 2012-12-22 18:09:02 +0000 | [diff] [blame] | 325 | if ((DemandedMask & (~LHSKnownZero) & RHSKnownOne) == |
Chris Lattner | 7e04491 | 2010-01-04 07:17:19 +0000 | [diff] [blame] | 326 | (DemandedMask & (~LHSKnownZero))) |
| 327 | return I->getOperand(1); |
Craig Topper | 4c94775 | 2012-12-22 18:09:02 +0000 | [diff] [blame] | 328 | |
Chris Lattner | 7e04491 | 2010-01-04 07:17:19 +0000 | [diff] [blame] | 329 | // If the RHS is a constant, see if we can simplify it. |
| 330 | if (ShrinkDemandedConstant(I, 1, DemandedMask)) |
| 331 | return I; |
Craig Topper | 4c94775 | 2012-12-22 18:09:02 +0000 | [diff] [blame] | 332 | |
Chris Lattner | 7e04491 | 2010-01-04 07:17:19 +0000 | [diff] [blame] | 333 | // Output known-0 bits are only known if clear in both the LHS & RHS. |
Duncan Sands | c8a3e56 | 2010-01-29 06:18:46 +0000 | [diff] [blame] | 334 | KnownZero = RHSKnownZero & LHSKnownZero; |
Chris Lattner | 7e04491 | 2010-01-04 07:17:19 +0000 | [diff] [blame] | 335 | // Output known-1 are known to be set if set in either the LHS | RHS. |
Duncan Sands | c8a3e56 | 2010-01-29 06:18:46 +0000 | [diff] [blame] | 336 | KnownOne = RHSKnownOne | LHSKnownOne; |
Chris Lattner | 7e04491 | 2010-01-04 07:17:19 +0000 | [diff] [blame] | 337 | break; |
| 338 | case Instruction::Xor: { |
| 339 | if (SimplifyDemandedBits(I->getOperandUse(1), DemandedMask, |
| 340 | RHSKnownZero, RHSKnownOne, Depth+1) || |
Craig Topper | 4c94775 | 2012-12-22 18:09:02 +0000 | [diff] [blame] | 341 | SimplifyDemandedBits(I->getOperandUse(0), DemandedMask, |
Chris Lattner | 7e04491 | 2010-01-04 07:17:19 +0000 | [diff] [blame] | 342 | LHSKnownZero, LHSKnownOne, Depth+1)) |
| 343 | return I; |
Craig Topper | 4c94775 | 2012-12-22 18:09:02 +0000 | [diff] [blame] | 344 | assert(!(RHSKnownZero & RHSKnownOne) && "Bits known to be one AND zero?"); |
| 345 | assert(!(LHSKnownZero & LHSKnownOne) && "Bits known to be one AND zero?"); |
| 346 | |
Hal Finkel | 15aeaaf | 2014-09-07 19:21:07 +0000 | [diff] [blame] | 347 | // Output known-0 bits are known if clear or set in both the LHS & RHS. |
| 348 | APInt IKnownZero = (RHSKnownZero & LHSKnownZero) | |
| 349 | (RHSKnownOne & LHSKnownOne); |
| 350 | // Output known-1 are known to be set if set in only one of the LHS, RHS. |
| 351 | APInt IKnownOne = (RHSKnownZero & LHSKnownOne) | |
| 352 | (RHSKnownOne & LHSKnownZero); |
| 353 | |
| 354 | // If the client is only demanding bits that we know, return the known |
| 355 | // constant. |
| 356 | if ((DemandedMask & (IKnownZero|IKnownOne)) == DemandedMask) |
| 357 | return Constant::getIntegerValue(VTy, IKnownOne); |
| 358 | |
Chris Lattner | 7e04491 | 2010-01-04 07:17:19 +0000 | [diff] [blame] | 359 | // If all of the demanded bits are known zero on one side, return the other. |
| 360 | // These bits cannot contribute to the result of the 'xor'. |
| 361 | if ((DemandedMask & RHSKnownZero) == DemandedMask) |
| 362 | return I->getOperand(0); |
| 363 | if ((DemandedMask & LHSKnownZero) == DemandedMask) |
| 364 | return I->getOperand(1); |
Craig Topper | 4c94775 | 2012-12-22 18:09:02 +0000 | [diff] [blame] | 365 | |
Chris Lattner | 7e04491 | 2010-01-04 07:17:19 +0000 | [diff] [blame] | 366 | // If all of the demanded bits are known to be zero on one side or the |
| 367 | // other, turn this into an *inclusive* or. |
Sylvestre Ledru | 91ce36c | 2012-09-27 10:14:43 +0000 | [diff] [blame] | 368 | // e.g. (A & C1)^(B & C2) -> (A & C1)|(B & C2) iff C1&C2 == 0 |
Chris Lattner | 7e04491 | 2010-01-04 07:17:19 +0000 | [diff] [blame] | 369 | if ((DemandedMask & ~RHSKnownZero & ~LHSKnownZero) == 0) { |
Craig Topper | 4c94775 | 2012-12-22 18:09:02 +0000 | [diff] [blame] | 370 | Instruction *Or = |
Chris Lattner | 7e04491 | 2010-01-04 07:17:19 +0000 | [diff] [blame] | 371 | BinaryOperator::CreateOr(I->getOperand(0), I->getOperand(1), |
| 372 | I->getName()); |
Eli Friedman | 6efb64e | 2011-05-19 01:20:42 +0000 | [diff] [blame] | 373 | return InsertNewInstWith(Or, *I); |
Chris Lattner | 7e04491 | 2010-01-04 07:17:19 +0000 | [diff] [blame] | 374 | } |
Craig Topper | 4c94775 | 2012-12-22 18:09:02 +0000 | [diff] [blame] | 375 | |
Chris Lattner | 7e04491 | 2010-01-04 07:17:19 +0000 | [diff] [blame] | 376 | // If all of the demanded bits on one side are known, and all of the set |
| 377 | // bits on that side are also known to be set on the other side, turn this |
| 378 | // into an AND, as we know the bits will be cleared. |
Sylvestre Ledru | 91ce36c | 2012-09-27 10:14:43 +0000 | [diff] [blame] | 379 | // e.g. (X | C1) ^ C2 --> (X | C1) & ~C2 iff (C1&C2) == C2 |
Craig Topper | 4c94775 | 2012-12-22 18:09:02 +0000 | [diff] [blame] | 380 | if ((DemandedMask & (RHSKnownZero|RHSKnownOne)) == DemandedMask) { |
Chris Lattner | 7e04491 | 2010-01-04 07:17:19 +0000 | [diff] [blame] | 381 | // all known |
| 382 | if ((RHSKnownOne & LHSKnownOne) == RHSKnownOne) { |
| 383 | Constant *AndC = Constant::getIntegerValue(VTy, |
| 384 | ~RHSKnownOne & DemandedMask); |
Benjamin Kramer | 547b6c5 | 2011-09-27 20:39:19 +0000 | [diff] [blame] | 385 | Instruction *And = BinaryOperator::CreateAnd(I->getOperand(0), AndC); |
Eli Friedman | 6efb64e | 2011-05-19 01:20:42 +0000 | [diff] [blame] | 386 | return InsertNewInstWith(And, *I); |
Chris Lattner | 7e04491 | 2010-01-04 07:17:19 +0000 | [diff] [blame] | 387 | } |
| 388 | } |
Craig Topper | 4c94775 | 2012-12-22 18:09:02 +0000 | [diff] [blame] | 389 | |
Chris Lattner | 7e04491 | 2010-01-04 07:17:19 +0000 | [diff] [blame] | 390 | // If the RHS is a constant, see if we can simplify it. |
| 391 | // FIXME: for XOR, we prefer to force bits to 1 if they will make a -1. |
| 392 | if (ShrinkDemandedConstant(I, 1, DemandedMask)) |
| 393 | return I; |
Craig Topper | 4c94775 | 2012-12-22 18:09:02 +0000 | [diff] [blame] | 394 | |
Chris Lattner | 7e04491 | 2010-01-04 07:17:19 +0000 | [diff] [blame] | 395 | // If our LHS is an 'and' and if it has one use, and if any of the bits we |
| 396 | // are flipping are known to be set, then the xor is just resetting those |
| 397 | // bits to zero. We can just knock out bits from the 'and' and the 'xor', |
| 398 | // simplifying both of them. |
| 399 | if (Instruction *LHSInst = dyn_cast<Instruction>(I->getOperand(0))) |
| 400 | if (LHSInst->getOpcode() == Instruction::And && LHSInst->hasOneUse() && |
| 401 | isa<ConstantInt>(I->getOperand(1)) && |
| 402 | isa<ConstantInt>(LHSInst->getOperand(1)) && |
| 403 | (LHSKnownOne & RHSKnownOne & DemandedMask) != 0) { |
| 404 | ConstantInt *AndRHS = cast<ConstantInt>(LHSInst->getOperand(1)); |
| 405 | ConstantInt *XorRHS = cast<ConstantInt>(I->getOperand(1)); |
| 406 | APInt NewMask = ~(LHSKnownOne & RHSKnownOne & DemandedMask); |
Craig Topper | 4c94775 | 2012-12-22 18:09:02 +0000 | [diff] [blame] | 407 | |
Chris Lattner | 7e04491 | 2010-01-04 07:17:19 +0000 | [diff] [blame] | 408 | Constant *AndC = |
| 409 | ConstantInt::get(I->getType(), NewMask & AndRHS->getValue()); |
Benjamin Kramer | 547b6c5 | 2011-09-27 20:39:19 +0000 | [diff] [blame] | 410 | Instruction *NewAnd = BinaryOperator::CreateAnd(I->getOperand(0), AndC); |
Eli Friedman | 6efb64e | 2011-05-19 01:20:42 +0000 | [diff] [blame] | 411 | InsertNewInstWith(NewAnd, *I); |
Craig Topper | 4c94775 | 2012-12-22 18:09:02 +0000 | [diff] [blame] | 412 | |
Chris Lattner | 7e04491 | 2010-01-04 07:17:19 +0000 | [diff] [blame] | 413 | Constant *XorC = |
| 414 | ConstantInt::get(I->getType(), NewMask & XorRHS->getValue()); |
Benjamin Kramer | 547b6c5 | 2011-09-27 20:39:19 +0000 | [diff] [blame] | 415 | Instruction *NewXor = BinaryOperator::CreateXor(NewAnd, XorC); |
Eli Friedman | 6efb64e | 2011-05-19 01:20:42 +0000 | [diff] [blame] | 416 | return InsertNewInstWith(NewXor, *I); |
Chris Lattner | 7e04491 | 2010-01-04 07:17:19 +0000 | [diff] [blame] | 417 | } |
Duncan Sands | c8a3e56 | 2010-01-29 06:18:46 +0000 | [diff] [blame] | 418 | |
| 419 | // Output known-0 bits are known if clear or set in both the LHS & RHS. |
| 420 | KnownZero= (RHSKnownZero & LHSKnownZero) | (RHSKnownOne & LHSKnownOne); |
| 421 | // Output known-1 are known to be set if set in only one of the LHS, RHS. |
| 422 | KnownOne = (RHSKnownZero & LHSKnownOne) | (RHSKnownOne & LHSKnownZero); |
Chris Lattner | 7e04491 | 2010-01-04 07:17:19 +0000 | [diff] [blame] | 423 | break; |
| 424 | } |
| 425 | case Instruction::Select: |
| 426 | if (SimplifyDemandedBits(I->getOperandUse(2), DemandedMask, |
| 427 | RHSKnownZero, RHSKnownOne, Depth+1) || |
Craig Topper | 4c94775 | 2012-12-22 18:09:02 +0000 | [diff] [blame] | 428 | SimplifyDemandedBits(I->getOperandUse(1), DemandedMask, |
Chris Lattner | 7e04491 | 2010-01-04 07:17:19 +0000 | [diff] [blame] | 429 | LHSKnownZero, LHSKnownOne, Depth+1)) |
| 430 | return I; |
Craig Topper | 4c94775 | 2012-12-22 18:09:02 +0000 | [diff] [blame] | 431 | assert(!(RHSKnownZero & RHSKnownOne) && "Bits known to be one AND zero?"); |
| 432 | assert(!(LHSKnownZero & LHSKnownOne) && "Bits known to be one AND zero?"); |
| 433 | |
Chris Lattner | 7e04491 | 2010-01-04 07:17:19 +0000 | [diff] [blame] | 434 | // If the operands are constants, see if we can simplify them. |
| 435 | if (ShrinkDemandedConstant(I, 1, DemandedMask) || |
| 436 | ShrinkDemandedConstant(I, 2, DemandedMask)) |
| 437 | return I; |
Craig Topper | 4c94775 | 2012-12-22 18:09:02 +0000 | [diff] [blame] | 438 | |
Chris Lattner | 7e04491 | 2010-01-04 07:17:19 +0000 | [diff] [blame] | 439 | // Only known if known in both the LHS and RHS. |
Duncan Sands | c8a3e56 | 2010-01-29 06:18:46 +0000 | [diff] [blame] | 440 | KnownOne = RHSKnownOne & LHSKnownOne; |
| 441 | KnownZero = RHSKnownZero & LHSKnownZero; |
Chris Lattner | 7e04491 | 2010-01-04 07:17:19 +0000 | [diff] [blame] | 442 | break; |
| 443 | case Instruction::Trunc: { |
| 444 | unsigned truncBf = I->getOperand(0)->getType()->getScalarSizeInBits(); |
Jay Foad | 583abbc | 2010-12-07 08:25:19 +0000 | [diff] [blame] | 445 | DemandedMask = DemandedMask.zext(truncBf); |
| 446 | KnownZero = KnownZero.zext(truncBf); |
| 447 | KnownOne = KnownOne.zext(truncBf); |
Craig Topper | 4c94775 | 2012-12-22 18:09:02 +0000 | [diff] [blame] | 448 | if (SimplifyDemandedBits(I->getOperandUse(0), DemandedMask, |
Duncan Sands | c8a3e56 | 2010-01-29 06:18:46 +0000 | [diff] [blame] | 449 | KnownZero, KnownOne, Depth+1)) |
Chris Lattner | 7e04491 | 2010-01-04 07:17:19 +0000 | [diff] [blame] | 450 | return I; |
Jay Foad | 583abbc | 2010-12-07 08:25:19 +0000 | [diff] [blame] | 451 | DemandedMask = DemandedMask.trunc(BitWidth); |
| 452 | KnownZero = KnownZero.trunc(BitWidth); |
| 453 | KnownOne = KnownOne.trunc(BitWidth); |
Craig Topper | 4c94775 | 2012-12-22 18:09:02 +0000 | [diff] [blame] | 454 | assert(!(KnownZero & KnownOne) && "Bits known to be one AND zero?"); |
Chris Lattner | 7e04491 | 2010-01-04 07:17:19 +0000 | [diff] [blame] | 455 | break; |
| 456 | } |
| 457 | case Instruction::BitCast: |
Duncan Sands | 9dff9be | 2010-02-15 16:12:20 +0000 | [diff] [blame] | 458 | if (!I->getOperand(0)->getType()->isIntOrIntVectorTy()) |
Craig Topper | f40110f | 2014-04-25 05:29:35 +0000 | [diff] [blame] | 459 | return nullptr; // vector->int or fp->int? |
Chris Lattner | 7e04491 | 2010-01-04 07:17:19 +0000 | [diff] [blame] | 460 | |
Chris Lattner | 229907c | 2011-07-18 04:54:35 +0000 | [diff] [blame] | 461 | if (VectorType *DstVTy = dyn_cast<VectorType>(I->getType())) { |
| 462 | if (VectorType *SrcVTy = |
Chris Lattner | 7e04491 | 2010-01-04 07:17:19 +0000 | [diff] [blame] | 463 | dyn_cast<VectorType>(I->getOperand(0)->getType())) { |
| 464 | if (DstVTy->getNumElements() != SrcVTy->getNumElements()) |
| 465 | // Don't touch a bitcast between vectors of different element counts. |
Craig Topper | f40110f | 2014-04-25 05:29:35 +0000 | [diff] [blame] | 466 | return nullptr; |
Chris Lattner | 7e04491 | 2010-01-04 07:17:19 +0000 | [diff] [blame] | 467 | } else |
| 468 | // Don't touch a scalar-to-vector bitcast. |
Craig Topper | f40110f | 2014-04-25 05:29:35 +0000 | [diff] [blame] | 469 | return nullptr; |
Duncan Sands | 19d0b47 | 2010-02-16 11:11:14 +0000 | [diff] [blame] | 470 | } else if (I->getOperand(0)->getType()->isVectorTy()) |
Chris Lattner | 7e04491 | 2010-01-04 07:17:19 +0000 | [diff] [blame] | 471 | // Don't touch a vector-to-scalar bitcast. |
Craig Topper | f40110f | 2014-04-25 05:29:35 +0000 | [diff] [blame] | 472 | return nullptr; |
Chris Lattner | 7e04491 | 2010-01-04 07:17:19 +0000 | [diff] [blame] | 473 | |
| 474 | if (SimplifyDemandedBits(I->getOperandUse(0), DemandedMask, |
Duncan Sands | c8a3e56 | 2010-01-29 06:18:46 +0000 | [diff] [blame] | 475 | KnownZero, KnownOne, Depth+1)) |
Chris Lattner | 7e04491 | 2010-01-04 07:17:19 +0000 | [diff] [blame] | 476 | return I; |
Craig Topper | 4c94775 | 2012-12-22 18:09:02 +0000 | [diff] [blame] | 477 | assert(!(KnownZero & KnownOne) && "Bits known to be one AND zero?"); |
Chris Lattner | 7e04491 | 2010-01-04 07:17:19 +0000 | [diff] [blame] | 478 | break; |
| 479 | case Instruction::ZExt: { |
| 480 | // Compute the bits in the result that are not present in the input. |
| 481 | unsigned SrcBitWidth =I->getOperand(0)->getType()->getScalarSizeInBits(); |
Craig Topper | 4c94775 | 2012-12-22 18:09:02 +0000 | [diff] [blame] | 482 | |
Jay Foad | 583abbc | 2010-12-07 08:25:19 +0000 | [diff] [blame] | 483 | DemandedMask = DemandedMask.trunc(SrcBitWidth); |
| 484 | KnownZero = KnownZero.trunc(SrcBitWidth); |
| 485 | KnownOne = KnownOne.trunc(SrcBitWidth); |
Chris Lattner | 7e04491 | 2010-01-04 07:17:19 +0000 | [diff] [blame] | 486 | if (SimplifyDemandedBits(I->getOperandUse(0), DemandedMask, |
Duncan Sands | c8a3e56 | 2010-01-29 06:18:46 +0000 | [diff] [blame] | 487 | KnownZero, KnownOne, Depth+1)) |
Chris Lattner | 7e04491 | 2010-01-04 07:17:19 +0000 | [diff] [blame] | 488 | return I; |
Jay Foad | 583abbc | 2010-12-07 08:25:19 +0000 | [diff] [blame] | 489 | DemandedMask = DemandedMask.zext(BitWidth); |
| 490 | KnownZero = KnownZero.zext(BitWidth); |
| 491 | KnownOne = KnownOne.zext(BitWidth); |
Craig Topper | 4c94775 | 2012-12-22 18:09:02 +0000 | [diff] [blame] | 492 | assert(!(KnownZero & KnownOne) && "Bits known to be one AND zero?"); |
Chris Lattner | 7e04491 | 2010-01-04 07:17:19 +0000 | [diff] [blame] | 493 | // The top bits are known to be zero. |
Duncan Sands | c8a3e56 | 2010-01-29 06:18:46 +0000 | [diff] [blame] | 494 | KnownZero |= APInt::getHighBitsSet(BitWidth, BitWidth - SrcBitWidth); |
Chris Lattner | 7e04491 | 2010-01-04 07:17:19 +0000 | [diff] [blame] | 495 | break; |
| 496 | } |
| 497 | case Instruction::SExt: { |
| 498 | // Compute the bits in the result that are not present in the input. |
| 499 | unsigned SrcBitWidth =I->getOperand(0)->getType()->getScalarSizeInBits(); |
Craig Topper | 4c94775 | 2012-12-22 18:09:02 +0000 | [diff] [blame] | 500 | |
| 501 | APInt InputDemandedBits = DemandedMask & |
Chris Lattner | 7e04491 | 2010-01-04 07:17:19 +0000 | [diff] [blame] | 502 | APInt::getLowBitsSet(BitWidth, SrcBitWidth); |
| 503 | |
| 504 | APInt NewBits(APInt::getHighBitsSet(BitWidth, BitWidth - SrcBitWidth)); |
| 505 | // If any of the sign extended bits are demanded, we know that the sign |
| 506 | // bit is demanded. |
| 507 | if ((NewBits & DemandedMask) != 0) |
Jay Foad | 25a5e4c | 2010-12-01 08:53:58 +0000 | [diff] [blame] | 508 | InputDemandedBits.setBit(SrcBitWidth-1); |
Craig Topper | 4c94775 | 2012-12-22 18:09:02 +0000 | [diff] [blame] | 509 | |
Jay Foad | 583abbc | 2010-12-07 08:25:19 +0000 | [diff] [blame] | 510 | InputDemandedBits = InputDemandedBits.trunc(SrcBitWidth); |
| 511 | KnownZero = KnownZero.trunc(SrcBitWidth); |
| 512 | KnownOne = KnownOne.trunc(SrcBitWidth); |
Chris Lattner | 7e04491 | 2010-01-04 07:17:19 +0000 | [diff] [blame] | 513 | if (SimplifyDemandedBits(I->getOperandUse(0), InputDemandedBits, |
Duncan Sands | c8a3e56 | 2010-01-29 06:18:46 +0000 | [diff] [blame] | 514 | KnownZero, KnownOne, Depth+1)) |
Chris Lattner | 7e04491 | 2010-01-04 07:17:19 +0000 | [diff] [blame] | 515 | return I; |
Jay Foad | 583abbc | 2010-12-07 08:25:19 +0000 | [diff] [blame] | 516 | InputDemandedBits = InputDemandedBits.zext(BitWidth); |
| 517 | KnownZero = KnownZero.zext(BitWidth); |
| 518 | KnownOne = KnownOne.zext(BitWidth); |
Craig Topper | 4c94775 | 2012-12-22 18:09:02 +0000 | [diff] [blame] | 519 | assert(!(KnownZero & KnownOne) && "Bits known to be one AND zero?"); |
| 520 | |
Chris Lattner | 7e04491 | 2010-01-04 07:17:19 +0000 | [diff] [blame] | 521 | // If the sign bit of the input is known set or clear, then we know the |
| 522 | // top bits of the result. |
| 523 | |
| 524 | // If the input sign bit is known zero, or if the NewBits are not demanded |
| 525 | // convert this into a zero extension. |
Duncan Sands | c8a3e56 | 2010-01-29 06:18:46 +0000 | [diff] [blame] | 526 | if (KnownZero[SrcBitWidth-1] || (NewBits & ~DemandedMask) == NewBits) { |
Chris Lattner | 7e04491 | 2010-01-04 07:17:19 +0000 | [diff] [blame] | 527 | // Convert to ZExt cast |
| 528 | CastInst *NewCast = new ZExtInst(I->getOperand(0), VTy, I->getName()); |
Eli Friedman | 6efb64e | 2011-05-19 01:20:42 +0000 | [diff] [blame] | 529 | return InsertNewInstWith(NewCast, *I); |
Duncan Sands | c8a3e56 | 2010-01-29 06:18:46 +0000 | [diff] [blame] | 530 | } else if (KnownOne[SrcBitWidth-1]) { // Input sign bit known set |
| 531 | KnownOne |= NewBits; |
Chris Lattner | 7e04491 | 2010-01-04 07:17:19 +0000 | [diff] [blame] | 532 | } |
| 533 | break; |
| 534 | } |
| 535 | case Instruction::Add: { |
| 536 | // Figure out what the input bits are. If the top bits of the and result |
| 537 | // are not demanded, then the add doesn't demand them from its input |
| 538 | // either. |
| 539 | unsigned NLZ = DemandedMask.countLeadingZeros(); |
Craig Topper | 4c94775 | 2012-12-22 18:09:02 +0000 | [diff] [blame] | 540 | |
Chris Lattner | 7e04491 | 2010-01-04 07:17:19 +0000 | [diff] [blame] | 541 | // If there is a constant on the RHS, there are a variety of xformations |
| 542 | // we can do. |
| 543 | if (ConstantInt *RHS = dyn_cast<ConstantInt>(I->getOperand(1))) { |
| 544 | // If null, this should be simplified elsewhere. Some of the xforms here |
| 545 | // won't work if the RHS is zero. |
| 546 | if (RHS->isZero()) |
| 547 | break; |
Craig Topper | 4c94775 | 2012-12-22 18:09:02 +0000 | [diff] [blame] | 548 | |
Chris Lattner | 7e04491 | 2010-01-04 07:17:19 +0000 | [diff] [blame] | 549 | // If the top bit of the output is demanded, demand everything from the |
| 550 | // input. Otherwise, we demand all the input bits except NLZ top bits. |
| 551 | APInt InDemandedBits(APInt::getLowBitsSet(BitWidth, BitWidth - NLZ)); |
| 552 | |
| 553 | // Find information about known zero/one bits in the input. |
Craig Topper | 4c94775 | 2012-12-22 18:09:02 +0000 | [diff] [blame] | 554 | if (SimplifyDemandedBits(I->getOperandUse(0), InDemandedBits, |
Chris Lattner | 7e04491 | 2010-01-04 07:17:19 +0000 | [diff] [blame] | 555 | LHSKnownZero, LHSKnownOne, Depth+1)) |
| 556 | return I; |
| 557 | |
| 558 | // If the RHS of the add has bits set that can't affect the input, reduce |
| 559 | // the constant. |
| 560 | if (ShrinkDemandedConstant(I, 1, InDemandedBits)) |
| 561 | return I; |
Craig Topper | 4c94775 | 2012-12-22 18:09:02 +0000 | [diff] [blame] | 562 | |
Chris Lattner | 7e04491 | 2010-01-04 07:17:19 +0000 | [diff] [blame] | 563 | // Avoid excess work. |
| 564 | if (LHSKnownZero == 0 && LHSKnownOne == 0) |
| 565 | break; |
Craig Topper | 4c94775 | 2012-12-22 18:09:02 +0000 | [diff] [blame] | 566 | |
Chris Lattner | 7e04491 | 2010-01-04 07:17:19 +0000 | [diff] [blame] | 567 | // Turn it into OR if input bits are zero. |
| 568 | if ((LHSKnownZero & RHS->getValue()) == RHS->getValue()) { |
| 569 | Instruction *Or = |
| 570 | BinaryOperator::CreateOr(I->getOperand(0), I->getOperand(1), |
| 571 | I->getName()); |
Eli Friedman | 6efb64e | 2011-05-19 01:20:42 +0000 | [diff] [blame] | 572 | return InsertNewInstWith(Or, *I); |
Chris Lattner | 7e04491 | 2010-01-04 07:17:19 +0000 | [diff] [blame] | 573 | } |
Craig Topper | 4c94775 | 2012-12-22 18:09:02 +0000 | [diff] [blame] | 574 | |
Chris Lattner | 7e04491 | 2010-01-04 07:17:19 +0000 | [diff] [blame] | 575 | // We can say something about the output known-zero and known-one bits, |
| 576 | // depending on potential carries from the input constant and the |
| 577 | // unknowns. For example if the LHS is known to have at most the 0x0F0F0 |
| 578 | // bits set and the RHS constant is 0x01001, then we know we have a known |
| 579 | // one mask of 0x00001 and a known zero mask of 0xE0F0E. |
Craig Topper | 4c94775 | 2012-12-22 18:09:02 +0000 | [diff] [blame] | 580 | |
Chris Lattner | 7e04491 | 2010-01-04 07:17:19 +0000 | [diff] [blame] | 581 | // To compute this, we first compute the potential carry bits. These are |
| 582 | // the bits which may be modified. I'm not aware of a better way to do |
| 583 | // this scan. |
| 584 | const APInt &RHSVal = RHS->getValue(); |
| 585 | APInt CarryBits((~LHSKnownZero + RHSVal) ^ (~LHSKnownZero ^ RHSVal)); |
Craig Topper | 4c94775 | 2012-12-22 18:09:02 +0000 | [diff] [blame] | 586 | |
Chris Lattner | 7e04491 | 2010-01-04 07:17:19 +0000 | [diff] [blame] | 587 | // Now that we know which bits have carries, compute the known-1/0 sets. |
Craig Topper | 4c94775 | 2012-12-22 18:09:02 +0000 | [diff] [blame] | 588 | |
Chris Lattner | 7e04491 | 2010-01-04 07:17:19 +0000 | [diff] [blame] | 589 | // Bits are known one if they are known zero in one operand and one in the |
| 590 | // other, and there is no input carry. |
Craig Topper | 4c94775 | 2012-12-22 18:09:02 +0000 | [diff] [blame] | 591 | KnownOne = ((LHSKnownZero & RHSVal) | |
Duncan Sands | c8a3e56 | 2010-01-29 06:18:46 +0000 | [diff] [blame] | 592 | (LHSKnownOne & ~RHSVal)) & ~CarryBits; |
Craig Topper | 4c94775 | 2012-12-22 18:09:02 +0000 | [diff] [blame] | 593 | |
Chris Lattner | 7e04491 | 2010-01-04 07:17:19 +0000 | [diff] [blame] | 594 | // Bits are known zero if they are known zero in both operands and there |
| 595 | // is no input carry. |
Duncan Sands | c8a3e56 | 2010-01-29 06:18:46 +0000 | [diff] [blame] | 596 | KnownZero = LHSKnownZero & ~RHSVal & ~CarryBits; |
Chris Lattner | 7e04491 | 2010-01-04 07:17:19 +0000 | [diff] [blame] | 597 | } else { |
| 598 | // If the high-bits of this ADD are not demanded, then it does not demand |
| 599 | // the high bits of its LHS or RHS. |
| 600 | if (DemandedMask[BitWidth-1] == 0) { |
| 601 | // Right fill the mask of bits for this ADD to demand the most |
| 602 | // significant bit and all those below it. |
| 603 | APInt DemandedFromOps(APInt::getLowBitsSet(BitWidth, BitWidth-NLZ)); |
| 604 | if (SimplifyDemandedBits(I->getOperandUse(0), DemandedFromOps, |
| 605 | LHSKnownZero, LHSKnownOne, Depth+1) || |
| 606 | SimplifyDemandedBits(I->getOperandUse(1), DemandedFromOps, |
| 607 | LHSKnownZero, LHSKnownOne, Depth+1)) |
| 608 | return I; |
| 609 | } |
| 610 | } |
| 611 | break; |
| 612 | } |
| 613 | case Instruction::Sub: |
| 614 | // If the high-bits of this SUB are not demanded, then it does not demand |
| 615 | // the high bits of its LHS or RHS. |
| 616 | if (DemandedMask[BitWidth-1] == 0) { |
| 617 | // Right fill the mask of bits for this SUB to demand the most |
| 618 | // significant bit and all those below it. |
| 619 | uint32_t NLZ = DemandedMask.countLeadingZeros(); |
| 620 | APInt DemandedFromOps(APInt::getLowBitsSet(BitWidth, BitWidth-NLZ)); |
| 621 | if (SimplifyDemandedBits(I->getOperandUse(0), DemandedFromOps, |
| 622 | LHSKnownZero, LHSKnownOne, Depth+1) || |
| 623 | SimplifyDemandedBits(I->getOperandUse(1), DemandedFromOps, |
| 624 | LHSKnownZero, LHSKnownOne, Depth+1)) |
| 625 | return I; |
| 626 | } |
Benjamin Kramer | 010337c | 2011-12-24 17:31:38 +0000 | [diff] [blame] | 627 | |
Jay Foad | a0653a3 | 2014-05-14 21:14:37 +0000 | [diff] [blame] | 628 | // Otherwise just hand the sub off to computeKnownBits to fill in |
Chris Lattner | 7e04491 | 2010-01-04 07:17:19 +0000 | [diff] [blame] | 629 | // the known zeros and ones. |
Hal Finkel | 60db058 | 2014-09-07 18:57:58 +0000 | [diff] [blame] | 630 | computeKnownBits(V, KnownZero, KnownOne, Depth, CxtI); |
Benjamin Kramer | 010337c | 2011-12-24 17:31:38 +0000 | [diff] [blame] | 631 | |
| 632 | // Turn this into a xor if LHS is 2^n-1 and the remaining bits are known |
| 633 | // zero. |
| 634 | if (ConstantInt *C0 = dyn_cast<ConstantInt>(I->getOperand(0))) { |
| 635 | APInt I0 = C0->getValue(); |
| 636 | if ((I0 + 1).isPowerOf2() && (I0 | KnownZero).isAllOnesValue()) { |
| 637 | Instruction *Xor = BinaryOperator::CreateXor(I->getOperand(1), C0); |
| 638 | return InsertNewInstWith(Xor, *I); |
| 639 | } |
| 640 | } |
Chris Lattner | 7e04491 | 2010-01-04 07:17:19 +0000 | [diff] [blame] | 641 | break; |
| 642 | case Instruction::Shl: |
| 643 | if (ConstantInt *SA = dyn_cast<ConstantInt>(I->getOperand(1))) { |
Shuxin Yang | 63e999e | 2012-12-04 00:04:54 +0000 | [diff] [blame] | 644 | { |
| 645 | Value *VarX; ConstantInt *C1; |
| 646 | if (match(I->getOperand(0), m_Shr(m_Value(VarX), m_ConstantInt(C1)))) { |
| 647 | Instruction *Shr = cast<Instruction>(I->getOperand(0)); |
| 648 | Value *R = SimplifyShrShlDemandedBits(Shr, I, DemandedMask, |
| 649 | KnownZero, KnownOne); |
| 650 | if (R) |
| 651 | return R; |
| 652 | } |
| 653 | } |
| 654 | |
Chris Lattner | 768003c | 2011-02-10 05:09:34 +0000 | [diff] [blame] | 655 | uint64_t ShiftAmt = SA->getLimitedValue(BitWidth-1); |
Chris Lattner | 7e04491 | 2010-01-04 07:17:19 +0000 | [diff] [blame] | 656 | APInt DemandedMaskIn(DemandedMask.lshr(ShiftAmt)); |
Craig Topper | 4c94775 | 2012-12-22 18:09:02 +0000 | [diff] [blame] | 657 | |
Chris Lattner | 768003c | 2011-02-10 05:09:34 +0000 | [diff] [blame] | 658 | // If the shift is NUW/NSW, then it does demand the high bits. |
| 659 | ShlOperator *IOp = cast<ShlOperator>(I); |
| 660 | if (IOp->hasNoSignedWrap()) |
| 661 | DemandedMaskIn |= APInt::getHighBitsSet(BitWidth, ShiftAmt+1); |
| 662 | else if (IOp->hasNoUnsignedWrap()) |
| 663 | DemandedMaskIn |= APInt::getHighBitsSet(BitWidth, ShiftAmt); |
Craig Topper | 4c94775 | 2012-12-22 18:09:02 +0000 | [diff] [blame] | 664 | |
| 665 | if (SimplifyDemandedBits(I->getOperandUse(0), DemandedMaskIn, |
Duncan Sands | c8a3e56 | 2010-01-29 06:18:46 +0000 | [diff] [blame] | 666 | KnownZero, KnownOne, Depth+1)) |
Chris Lattner | 7e04491 | 2010-01-04 07:17:19 +0000 | [diff] [blame] | 667 | return I; |
Duncan Sands | c8a3e56 | 2010-01-29 06:18:46 +0000 | [diff] [blame] | 668 | assert(!(KnownZero & KnownOne) && "Bits known to be one AND zero?"); |
| 669 | KnownZero <<= ShiftAmt; |
| 670 | KnownOne <<= ShiftAmt; |
Chris Lattner | 7e04491 | 2010-01-04 07:17:19 +0000 | [diff] [blame] | 671 | // low bits known zero. |
| 672 | if (ShiftAmt) |
Duncan Sands | c8a3e56 | 2010-01-29 06:18:46 +0000 | [diff] [blame] | 673 | KnownZero |= APInt::getLowBitsSet(BitWidth, ShiftAmt); |
Chris Lattner | 7e04491 | 2010-01-04 07:17:19 +0000 | [diff] [blame] | 674 | } |
| 675 | break; |
| 676 | case Instruction::LShr: |
| 677 | // For a logical shift right |
| 678 | if (ConstantInt *SA = dyn_cast<ConstantInt>(I->getOperand(1))) { |
Chris Lattner | 768003c | 2011-02-10 05:09:34 +0000 | [diff] [blame] | 679 | uint64_t ShiftAmt = SA->getLimitedValue(BitWidth-1); |
Craig Topper | 4c94775 | 2012-12-22 18:09:02 +0000 | [diff] [blame] | 680 | |
Chris Lattner | 7e04491 | 2010-01-04 07:17:19 +0000 | [diff] [blame] | 681 | // Unsigned shift right. |
| 682 | APInt DemandedMaskIn(DemandedMask.shl(ShiftAmt)); |
Craig Topper | 4c94775 | 2012-12-22 18:09:02 +0000 | [diff] [blame] | 683 | |
Chris Lattner | 768003c | 2011-02-10 05:09:34 +0000 | [diff] [blame] | 684 | // If the shift is exact, then it does demand the low bits (and knows that |
| 685 | // they are zero). |
| 686 | if (cast<LShrOperator>(I)->isExact()) |
| 687 | DemandedMaskIn |= APInt::getLowBitsSet(BitWidth, ShiftAmt); |
Craig Topper | 4c94775 | 2012-12-22 18:09:02 +0000 | [diff] [blame] | 688 | |
Chris Lattner | 7e04491 | 2010-01-04 07:17:19 +0000 | [diff] [blame] | 689 | if (SimplifyDemandedBits(I->getOperandUse(0), DemandedMaskIn, |
Duncan Sands | c8a3e56 | 2010-01-29 06:18:46 +0000 | [diff] [blame] | 690 | KnownZero, KnownOne, Depth+1)) |
Chris Lattner | 7e04491 | 2010-01-04 07:17:19 +0000 | [diff] [blame] | 691 | return I; |
Duncan Sands | c8a3e56 | 2010-01-29 06:18:46 +0000 | [diff] [blame] | 692 | assert(!(KnownZero & KnownOne) && "Bits known to be one AND zero?"); |
| 693 | KnownZero = APIntOps::lshr(KnownZero, ShiftAmt); |
| 694 | KnownOne = APIntOps::lshr(KnownOne, ShiftAmt); |
Chris Lattner | 7e04491 | 2010-01-04 07:17:19 +0000 | [diff] [blame] | 695 | if (ShiftAmt) { |
| 696 | // Compute the new bits that are at the top now. |
| 697 | APInt HighBits(APInt::getHighBitsSet(BitWidth, ShiftAmt)); |
Duncan Sands | c8a3e56 | 2010-01-29 06:18:46 +0000 | [diff] [blame] | 698 | KnownZero |= HighBits; // high bits known zero. |
Chris Lattner | 7e04491 | 2010-01-04 07:17:19 +0000 | [diff] [blame] | 699 | } |
| 700 | } |
| 701 | break; |
| 702 | case Instruction::AShr: |
| 703 | // If this is an arithmetic shift right and only the low-bit is set, we can |
| 704 | // always convert this into a logical shr, even if the shift amount is |
| 705 | // variable. The low bit of the shift cannot be an input sign bit unless |
| 706 | // the shift amount is >= the size of the datatype, which is undefined. |
| 707 | if (DemandedMask == 1) { |
| 708 | // Perform the logical shift right. |
| 709 | Instruction *NewVal = BinaryOperator::CreateLShr( |
| 710 | I->getOperand(0), I->getOperand(1), I->getName()); |
Eli Friedman | 6efb64e | 2011-05-19 01:20:42 +0000 | [diff] [blame] | 711 | return InsertNewInstWith(NewVal, *I); |
Craig Topper | 4c94775 | 2012-12-22 18:09:02 +0000 | [diff] [blame] | 712 | } |
Chris Lattner | 7e04491 | 2010-01-04 07:17:19 +0000 | [diff] [blame] | 713 | |
| 714 | // If the sign bit is the only bit demanded by this ashr, then there is no |
| 715 | // need to do it, the shift doesn't change the high bit. |
| 716 | if (DemandedMask.isSignBit()) |
| 717 | return I->getOperand(0); |
Craig Topper | 4c94775 | 2012-12-22 18:09:02 +0000 | [diff] [blame] | 718 | |
Chris Lattner | 7e04491 | 2010-01-04 07:17:19 +0000 | [diff] [blame] | 719 | if (ConstantInt *SA = dyn_cast<ConstantInt>(I->getOperand(1))) { |
Chris Lattner | 768003c | 2011-02-10 05:09:34 +0000 | [diff] [blame] | 720 | uint32_t ShiftAmt = SA->getLimitedValue(BitWidth-1); |
Craig Topper | 4c94775 | 2012-12-22 18:09:02 +0000 | [diff] [blame] | 721 | |
Chris Lattner | 7e04491 | 2010-01-04 07:17:19 +0000 | [diff] [blame] | 722 | // Signed shift right. |
| 723 | APInt DemandedMaskIn(DemandedMask.shl(ShiftAmt)); |
| 724 | // If any of the "high bits" are demanded, we should set the sign bit as |
| 725 | // demanded. |
| 726 | if (DemandedMask.countLeadingZeros() <= ShiftAmt) |
Jay Foad | 25a5e4c | 2010-12-01 08:53:58 +0000 | [diff] [blame] | 727 | DemandedMaskIn.setBit(BitWidth-1); |
Craig Topper | 4c94775 | 2012-12-22 18:09:02 +0000 | [diff] [blame] | 728 | |
Chris Lattner | 768003c | 2011-02-10 05:09:34 +0000 | [diff] [blame] | 729 | // If the shift is exact, then it does demand the low bits (and knows that |
| 730 | // they are zero). |
| 731 | if (cast<AShrOperator>(I)->isExact()) |
| 732 | DemandedMaskIn |= APInt::getLowBitsSet(BitWidth, ShiftAmt); |
Craig Topper | 4c94775 | 2012-12-22 18:09:02 +0000 | [diff] [blame] | 733 | |
Chris Lattner | 7e04491 | 2010-01-04 07:17:19 +0000 | [diff] [blame] | 734 | if (SimplifyDemandedBits(I->getOperandUse(0), DemandedMaskIn, |
Duncan Sands | c8a3e56 | 2010-01-29 06:18:46 +0000 | [diff] [blame] | 735 | KnownZero, KnownOne, Depth+1)) |
Chris Lattner | 7e04491 | 2010-01-04 07:17:19 +0000 | [diff] [blame] | 736 | return I; |
Duncan Sands | c8a3e56 | 2010-01-29 06:18:46 +0000 | [diff] [blame] | 737 | assert(!(KnownZero & KnownOne) && "Bits known to be one AND zero?"); |
Chris Lattner | 7e04491 | 2010-01-04 07:17:19 +0000 | [diff] [blame] | 738 | // Compute the new bits that are at the top now. |
| 739 | APInt HighBits(APInt::getHighBitsSet(BitWidth, ShiftAmt)); |
Duncan Sands | c8a3e56 | 2010-01-29 06:18:46 +0000 | [diff] [blame] | 740 | KnownZero = APIntOps::lshr(KnownZero, ShiftAmt); |
| 741 | KnownOne = APIntOps::lshr(KnownOne, ShiftAmt); |
Craig Topper | 4c94775 | 2012-12-22 18:09:02 +0000 | [diff] [blame] | 742 | |
Chris Lattner | 7e04491 | 2010-01-04 07:17:19 +0000 | [diff] [blame] | 743 | // Handle the sign bits. |
| 744 | APInt SignBit(APInt::getSignBit(BitWidth)); |
| 745 | // Adjust to where it is now in the mask. |
Craig Topper | 4c94775 | 2012-12-22 18:09:02 +0000 | [diff] [blame] | 746 | SignBit = APIntOps::lshr(SignBit, ShiftAmt); |
| 747 | |
Chris Lattner | 7e04491 | 2010-01-04 07:17:19 +0000 | [diff] [blame] | 748 | // If the input sign bit is known to be zero, or if none of the top bits |
| 749 | // are demanded, turn this into an unsigned shift right. |
Craig Topper | 4c94775 | 2012-12-22 18:09:02 +0000 | [diff] [blame] | 750 | if (BitWidth <= ShiftAmt || KnownZero[BitWidth-ShiftAmt-1] || |
Chris Lattner | 7e04491 | 2010-01-04 07:17:19 +0000 | [diff] [blame] | 751 | (HighBits & ~DemandedMask) == HighBits) { |
| 752 | // Perform the logical shift right. |
Nick Lewycky | 0c48afa | 2012-01-04 09:28:29 +0000 | [diff] [blame] | 753 | BinaryOperator *NewVal = BinaryOperator::CreateLShr(I->getOperand(0), |
| 754 | SA, I->getName()); |
| 755 | NewVal->setIsExact(cast<BinaryOperator>(I)->isExact()); |
Eli Friedman | 6efb64e | 2011-05-19 01:20:42 +0000 | [diff] [blame] | 756 | return InsertNewInstWith(NewVal, *I); |
Duncan Sands | c8a3e56 | 2010-01-29 06:18:46 +0000 | [diff] [blame] | 757 | } else if ((KnownOne & SignBit) != 0) { // New bits are known one. |
| 758 | KnownOne |= HighBits; |
Chris Lattner | 7e04491 | 2010-01-04 07:17:19 +0000 | [diff] [blame] | 759 | } |
| 760 | } |
| 761 | break; |
| 762 | case Instruction::SRem: |
| 763 | if (ConstantInt *Rem = dyn_cast<ConstantInt>(I->getOperand(1))) { |
Eli Friedman | a81a82d | 2011-03-09 01:28:35 +0000 | [diff] [blame] | 764 | // X % -1 demands all the bits because we don't want to introduce |
| 765 | // INT_MIN % -1 (== undef) by accident. |
| 766 | if (Rem->isAllOnesValue()) |
| 767 | break; |
Chris Lattner | 7e04491 | 2010-01-04 07:17:19 +0000 | [diff] [blame] | 768 | APInt RA = Rem->getValue().abs(); |
| 769 | if (RA.isPowerOf2()) { |
| 770 | if (DemandedMask.ult(RA)) // srem won't affect demanded bits |
| 771 | return I->getOperand(0); |
| 772 | |
| 773 | APInt LowBits = RA - 1; |
| 774 | APInt Mask2 = LowBits | APInt::getSignBit(BitWidth); |
| 775 | if (SimplifyDemandedBits(I->getOperandUse(0), Mask2, |
| 776 | LHSKnownZero, LHSKnownOne, Depth+1)) |
| 777 | return I; |
| 778 | |
Duncan Sands | 3a48b87 | 2010-01-28 17:22:42 +0000 | [diff] [blame] | 779 | // The low bits of LHS are unchanged by the srem. |
Duncan Sands | c8a3e56 | 2010-01-29 06:18:46 +0000 | [diff] [blame] | 780 | KnownZero = LHSKnownZero & LowBits; |
| 781 | KnownOne = LHSKnownOne & LowBits; |
Chris Lattner | 7e04491 | 2010-01-04 07:17:19 +0000 | [diff] [blame] | 782 | |
Duncan Sands | 3a48b87 | 2010-01-28 17:22:42 +0000 | [diff] [blame] | 783 | // If LHS is non-negative or has all low bits zero, then the upper bits |
| 784 | // are all zero. |
| 785 | if (LHSKnownZero[BitWidth-1] || ((LHSKnownZero & LowBits) == LowBits)) |
| 786 | KnownZero |= ~LowBits; |
| 787 | |
| 788 | // If LHS is negative and not all low bits are zero, then the upper bits |
| 789 | // are all one. |
| 790 | if (LHSKnownOne[BitWidth-1] && ((LHSKnownOne & LowBits) != 0)) |
| 791 | KnownOne |= ~LowBits; |
Chris Lattner | 7e04491 | 2010-01-04 07:17:19 +0000 | [diff] [blame] | 792 | |
Craig Topper | 4c94775 | 2012-12-22 18:09:02 +0000 | [diff] [blame] | 793 | assert(!(KnownZero & KnownOne) && "Bits known to be one AND zero?"); |
Chris Lattner | 7e04491 | 2010-01-04 07:17:19 +0000 | [diff] [blame] | 794 | } |
| 795 | } |
Nick Lewycky | e467979 | 2011-03-07 01:50:10 +0000 | [diff] [blame] | 796 | |
| 797 | // The sign bit is the LHS's sign bit, except when the result of the |
| 798 | // remainder is zero. |
| 799 | if (DemandedMask.isNegative() && KnownZero.isNonNegative()) { |
Nick Lewycky | e467979 | 2011-03-07 01:50:10 +0000 | [diff] [blame] | 800 | APInt LHSKnownZero(BitWidth, 0), LHSKnownOne(BitWidth, 0); |
Hal Finkel | 60db058 | 2014-09-07 18:57:58 +0000 | [diff] [blame] | 801 | computeKnownBits(I->getOperand(0), LHSKnownZero, LHSKnownOne, Depth+1, |
| 802 | CxtI); |
Nick Lewycky | e467979 | 2011-03-07 01:50:10 +0000 | [diff] [blame] | 803 | // If it's known zero, our sign bit is also zero. |
| 804 | if (LHSKnownZero.isNegative()) |
Benjamin Kramer | 21b972a | 2013-05-09 16:32:32 +0000 | [diff] [blame] | 805 | KnownZero.setBit(KnownZero.getBitWidth() - 1); |
Nick Lewycky | e467979 | 2011-03-07 01:50:10 +0000 | [diff] [blame] | 806 | } |
Chris Lattner | 7e04491 | 2010-01-04 07:17:19 +0000 | [diff] [blame] | 807 | break; |
| 808 | case Instruction::URem: { |
| 809 | APInt KnownZero2(BitWidth, 0), KnownOne2(BitWidth, 0); |
| 810 | APInt AllOnes = APInt::getAllOnesValue(BitWidth); |
| 811 | if (SimplifyDemandedBits(I->getOperandUse(0), AllOnes, |
| 812 | KnownZero2, KnownOne2, Depth+1) || |
| 813 | SimplifyDemandedBits(I->getOperandUse(1), AllOnes, |
| 814 | KnownZero2, KnownOne2, Depth+1)) |
| 815 | return I; |
| 816 | |
| 817 | unsigned Leaders = KnownZero2.countLeadingOnes(); |
| 818 | Leaders = std::max(Leaders, |
| 819 | KnownZero2.countLeadingOnes()); |
| 820 | KnownZero = APInt::getHighBitsSet(BitWidth, Leaders) & DemandedMask; |
| 821 | break; |
| 822 | } |
| 823 | case Instruction::Call: |
| 824 | if (IntrinsicInst *II = dyn_cast<IntrinsicInst>(I)) { |
| 825 | switch (II->getIntrinsicID()) { |
| 826 | default: break; |
| 827 | case Intrinsic::bswap: { |
| 828 | // If the only bits demanded come from one byte of the bswap result, |
| 829 | // just shift the input byte into position to eliminate the bswap. |
| 830 | unsigned NLZ = DemandedMask.countLeadingZeros(); |
| 831 | unsigned NTZ = DemandedMask.countTrailingZeros(); |
Craig Topper | 4c94775 | 2012-12-22 18:09:02 +0000 | [diff] [blame] | 832 | |
Chris Lattner | 7e04491 | 2010-01-04 07:17:19 +0000 | [diff] [blame] | 833 | // Round NTZ down to the next byte. If we have 11 trailing zeros, then |
| 834 | // we need all the bits down to bit 8. Likewise, round NLZ. If we |
| 835 | // have 14 leading zeros, round to 8. |
| 836 | NLZ &= ~7; |
| 837 | NTZ &= ~7; |
| 838 | // If we need exactly one byte, we can do this transformation. |
| 839 | if (BitWidth-NLZ-NTZ == 8) { |
| 840 | unsigned ResultBit = NTZ; |
| 841 | unsigned InputBit = BitWidth-NTZ-8; |
Craig Topper | 4c94775 | 2012-12-22 18:09:02 +0000 | [diff] [blame] | 842 | |
Chris Lattner | 7e04491 | 2010-01-04 07:17:19 +0000 | [diff] [blame] | 843 | // Replace this with either a left or right shift to get the byte into |
| 844 | // the right place. |
| 845 | Instruction *NewVal; |
| 846 | if (InputBit > ResultBit) |
Gabor Greif | 7943017 | 2010-06-24 12:35:13 +0000 | [diff] [blame] | 847 | NewVal = BinaryOperator::CreateLShr(II->getArgOperand(0), |
Chris Lattner | 7e04491 | 2010-01-04 07:17:19 +0000 | [diff] [blame] | 848 | ConstantInt::get(I->getType(), InputBit-ResultBit)); |
| 849 | else |
Gabor Greif | 7943017 | 2010-06-24 12:35:13 +0000 | [diff] [blame] | 850 | NewVal = BinaryOperator::CreateShl(II->getArgOperand(0), |
Chris Lattner | 7e04491 | 2010-01-04 07:17:19 +0000 | [diff] [blame] | 851 | ConstantInt::get(I->getType(), ResultBit-InputBit)); |
| 852 | NewVal->takeName(I); |
Eli Friedman | 6efb64e | 2011-05-19 01:20:42 +0000 | [diff] [blame] | 853 | return InsertNewInstWith(NewVal, *I); |
Chris Lattner | 7e04491 | 2010-01-04 07:17:19 +0000 | [diff] [blame] | 854 | } |
Craig Topper | 4c94775 | 2012-12-22 18:09:02 +0000 | [diff] [blame] | 855 | |
Chris Lattner | 7e04491 | 2010-01-04 07:17:19 +0000 | [diff] [blame] | 856 | // TODO: Could compute known zero/one bits based on the input. |
| 857 | break; |
| 858 | } |
Chad Rosier | b362884 | 2011-05-26 23:13:19 +0000 | [diff] [blame] | 859 | case Intrinsic::x86_sse42_crc32_64_64: |
Evan Cheng | e8d2e9e | 2011-05-20 00:54:37 +0000 | [diff] [blame] | 860 | KnownZero = APInt::getHighBitsSet(64, 32); |
Craig Topper | f40110f | 2014-04-25 05:29:35 +0000 | [diff] [blame] | 861 | return nullptr; |
Chris Lattner | 7e04491 | 2010-01-04 07:17:19 +0000 | [diff] [blame] | 862 | } |
| 863 | } |
Hal Finkel | 60db058 | 2014-09-07 18:57:58 +0000 | [diff] [blame] | 864 | computeKnownBits(V, KnownZero, KnownOne, Depth, CxtI); |
Chris Lattner | 7e04491 | 2010-01-04 07:17:19 +0000 | [diff] [blame] | 865 | break; |
| 866 | } |
Craig Topper | 4c94775 | 2012-12-22 18:09:02 +0000 | [diff] [blame] | 867 | |
Chris Lattner | 7e04491 | 2010-01-04 07:17:19 +0000 | [diff] [blame] | 868 | // If the client is only demanding bits that we know, return the known |
| 869 | // constant. |
Duncan Sands | c8a3e56 | 2010-01-29 06:18:46 +0000 | [diff] [blame] | 870 | if ((DemandedMask & (KnownZero|KnownOne)) == DemandedMask) |
| 871 | return Constant::getIntegerValue(VTy, KnownOne); |
Craig Topper | f40110f | 2014-04-25 05:29:35 +0000 | [diff] [blame] | 872 | return nullptr; |
Chris Lattner | 7e04491 | 2010-01-04 07:17:19 +0000 | [diff] [blame] | 873 | } |
| 874 | |
Shuxin Yang | 63e999e | 2012-12-04 00:04:54 +0000 | [diff] [blame] | 875 | /// Helper routine of SimplifyDemandedUseBits. It tries to simplify |
| 876 | /// "E1 = (X lsr C1) << C2", where the C1 and C2 are constant, into |
| 877 | /// "E2 = X << (C2 - C1)" or "E2 = X >> (C1 - C2)", depending on the sign |
| 878 | /// of "C2-C1". |
| 879 | /// |
| 880 | /// Suppose E1 and E2 are generally different in bits S={bm, bm+1, |
| 881 | /// ..., bn}, without considering the specific value X is holding. |
| 882 | /// This transformation is legal iff one of following conditions is hold: |
| 883 | /// 1) All the bit in S are 0, in this case E1 == E2. |
| 884 | /// 2) We don't care those bits in S, per the input DemandedMask. |
| 885 | /// 3) Combination of 1) and 2). Some bits in S are 0, and we don't care the |
| 886 | /// rest bits. |
| 887 | /// |
| 888 | /// Currently we only test condition 2). |
| 889 | /// |
| 890 | /// As with SimplifyDemandedUseBits, it returns NULL if the simplification was |
| 891 | /// not successful. |
| 892 | Value *InstCombiner::SimplifyShrShlDemandedBits(Instruction *Shr, |
| 893 | Instruction *Shl, APInt DemandedMask, APInt &KnownZero, APInt &KnownOne) { |
| 894 | |
Benjamin Kramer | 010f108 | 2013-08-30 14:35:35 +0000 | [diff] [blame] | 895 | const APInt &ShlOp1 = cast<ConstantInt>(Shl->getOperand(1))->getValue(); |
| 896 | const APInt &ShrOp1 = cast<ConstantInt>(Shr->getOperand(1))->getValue(); |
| 897 | if (!ShlOp1 || !ShrOp1) |
Craig Topper | f40110f | 2014-04-25 05:29:35 +0000 | [diff] [blame] | 898 | return nullptr; // Noop. |
Benjamin Kramer | 010f108 | 2013-08-30 14:35:35 +0000 | [diff] [blame] | 899 | |
| 900 | Value *VarX = Shr->getOperand(0); |
| 901 | Type *Ty = VarX->getType(); |
| 902 | unsigned BitWidth = Ty->getIntegerBitWidth(); |
| 903 | if (ShlOp1.uge(BitWidth) || ShrOp1.uge(BitWidth)) |
Craig Topper | f40110f | 2014-04-25 05:29:35 +0000 | [diff] [blame] | 904 | return nullptr; // Undef. |
Benjamin Kramer | 010f108 | 2013-08-30 14:35:35 +0000 | [diff] [blame] | 905 | |
| 906 | unsigned ShlAmt = ShlOp1.getZExtValue(); |
| 907 | unsigned ShrAmt = ShrOp1.getZExtValue(); |
Shuxin Yang | 63e999e | 2012-12-04 00:04:54 +0000 | [diff] [blame] | 908 | |
| 909 | KnownOne.clearAllBits(); |
| 910 | KnownZero = APInt::getBitsSet(KnownZero.getBitWidth(), 0, ShlAmt-1); |
| 911 | KnownZero &= DemandedMask; |
| 912 | |
Benjamin Kramer | 010f108 | 2013-08-30 14:35:35 +0000 | [diff] [blame] | 913 | APInt BitMask1(APInt::getAllOnesValue(BitWidth)); |
| 914 | APInt BitMask2(APInt::getAllOnesValue(BitWidth)); |
Shuxin Yang | 63e999e | 2012-12-04 00:04:54 +0000 | [diff] [blame] | 915 | |
| 916 | bool isLshr = (Shr->getOpcode() == Instruction::LShr); |
| 917 | BitMask1 = isLshr ? (BitMask1.lshr(ShrAmt) << ShlAmt) : |
| 918 | (BitMask1.ashr(ShrAmt) << ShlAmt); |
| 919 | |
| 920 | if (ShrAmt <= ShlAmt) { |
| 921 | BitMask2 <<= (ShlAmt - ShrAmt); |
| 922 | } else { |
| 923 | BitMask2 = isLshr ? BitMask2.lshr(ShrAmt - ShlAmt): |
| 924 | BitMask2.ashr(ShrAmt - ShlAmt); |
| 925 | } |
| 926 | |
| 927 | // Check if condition-2 (see the comment to this function) is satified. |
| 928 | if ((BitMask1 & DemandedMask) == (BitMask2 & DemandedMask)) { |
| 929 | if (ShrAmt == ShlAmt) |
| 930 | return VarX; |
| 931 | |
| 932 | if (!Shr->hasOneUse()) |
Craig Topper | f40110f | 2014-04-25 05:29:35 +0000 | [diff] [blame] | 933 | return nullptr; |
Shuxin Yang | 63e999e | 2012-12-04 00:04:54 +0000 | [diff] [blame] | 934 | |
| 935 | BinaryOperator *New; |
| 936 | if (ShrAmt < ShlAmt) { |
| 937 | Constant *Amt = ConstantInt::get(VarX->getType(), ShlAmt - ShrAmt); |
| 938 | New = BinaryOperator::CreateShl(VarX, Amt); |
| 939 | BinaryOperator *Orig = cast<BinaryOperator>(Shl); |
| 940 | New->setHasNoSignedWrap(Orig->hasNoSignedWrap()); |
| 941 | New->setHasNoUnsignedWrap(Orig->hasNoUnsignedWrap()); |
| 942 | } else { |
| 943 | Constant *Amt = ConstantInt::get(VarX->getType(), ShrAmt - ShlAmt); |
Shuxin Yang | 86c0e23 | 2012-12-04 03:28:32 +0000 | [diff] [blame] | 944 | New = isLshr ? BinaryOperator::CreateLShr(VarX, Amt) : |
| 945 | BinaryOperator::CreateAShr(VarX, Amt); |
Shuxin Yang | 81b3678 | 2012-12-12 00:29:03 +0000 | [diff] [blame] | 946 | if (cast<BinaryOperator>(Shr)->isExact()) |
| 947 | New->setIsExact(true); |
Shuxin Yang | 63e999e | 2012-12-04 00:04:54 +0000 | [diff] [blame] | 948 | } |
| 949 | |
| 950 | return InsertNewInstWith(New, *Shl); |
| 951 | } |
| 952 | |
Craig Topper | f40110f | 2014-04-25 05:29:35 +0000 | [diff] [blame] | 953 | return nullptr; |
Shuxin Yang | 63e999e | 2012-12-04 00:04:54 +0000 | [diff] [blame] | 954 | } |
Chris Lattner | 7e04491 | 2010-01-04 07:17:19 +0000 | [diff] [blame] | 955 | |
| 956 | /// SimplifyDemandedVectorElts - The specified value produces a vector with |
| 957 | /// any number of elements. DemandedElts contains the set of elements that are |
| 958 | /// actually used by the caller. This method analyzes which elements of the |
| 959 | /// operand are undef and returns that information in UndefElts. |
| 960 | /// |
| 961 | /// If the information about demanded elements can be used to simplify the |
| 962 | /// operation, the operation is simplified, then the resultant value is |
| 963 | /// returned. This returns null if no change was made. |
| 964 | Value *InstCombiner::SimplifyDemandedVectorElts(Value *V, APInt DemandedElts, |
Chris Lattner | b22423c | 2010-02-08 23:56:03 +0000 | [diff] [blame] | 965 | APInt &UndefElts, |
Chris Lattner | 7e04491 | 2010-01-04 07:17:19 +0000 | [diff] [blame] | 966 | unsigned Depth) { |
| 967 | unsigned VWidth = cast<VectorType>(V->getType())->getNumElements(); |
| 968 | APInt EltMask(APInt::getAllOnesValue(VWidth)); |
| 969 | assert((DemandedElts & ~EltMask) == 0 && "Invalid DemandedElts!"); |
| 970 | |
| 971 | if (isa<UndefValue>(V)) { |
| 972 | // If the entire vector is undefined, just return this info. |
| 973 | UndefElts = EltMask; |
Craig Topper | f40110f | 2014-04-25 05:29:35 +0000 | [diff] [blame] | 974 | return nullptr; |
Chris Lattner | b22423c | 2010-02-08 23:56:03 +0000 | [diff] [blame] | 975 | } |
Craig Topper | 4c94775 | 2012-12-22 18:09:02 +0000 | [diff] [blame] | 976 | |
Chris Lattner | b22423c | 2010-02-08 23:56:03 +0000 | [diff] [blame] | 977 | if (DemandedElts == 0) { // If nothing is demanded, provide undef. |
Chris Lattner | 7e04491 | 2010-01-04 07:17:19 +0000 | [diff] [blame] | 978 | UndefElts = EltMask; |
| 979 | return UndefValue::get(V->getType()); |
| 980 | } |
| 981 | |
| 982 | UndefElts = 0; |
Craig Topper | 4c94775 | 2012-12-22 18:09:02 +0000 | [diff] [blame] | 983 | |
Chris Lattner | 6705883 | 2012-01-25 06:48:06 +0000 | [diff] [blame] | 984 | // Handle ConstantAggregateZero, ConstantVector, ConstantDataSequential. |
| 985 | if (Constant *C = dyn_cast<Constant>(V)) { |
| 986 | // Check if this is identity. If so, return 0 since we are not simplifying |
| 987 | // anything. |
| 988 | if (DemandedElts.isAllOnesValue()) |
Craig Topper | f40110f | 2014-04-25 05:29:35 +0000 | [diff] [blame] | 989 | return nullptr; |
Chris Lattner | 6705883 | 2012-01-25 06:48:06 +0000 | [diff] [blame] | 990 | |
Chris Lattner | 229907c | 2011-07-18 04:54:35 +0000 | [diff] [blame] | 991 | Type *EltTy = cast<VectorType>(V->getType())->getElementType(); |
Chris Lattner | 7e04491 | 2010-01-04 07:17:19 +0000 | [diff] [blame] | 992 | Constant *Undef = UndefValue::get(EltTy); |
Craig Topper | 4c94775 | 2012-12-22 18:09:02 +0000 | [diff] [blame] | 993 | |
Chris Lattner | 6705883 | 2012-01-25 06:48:06 +0000 | [diff] [blame] | 994 | SmallVector<Constant*, 16> Elts; |
| 995 | for (unsigned i = 0; i != VWidth; ++i) { |
Chris Lattner | 7e04491 | 2010-01-04 07:17:19 +0000 | [diff] [blame] | 996 | if (!DemandedElts[i]) { // If not demanded, set to undef. |
| 997 | Elts.push_back(Undef); |
Jay Foad | 25a5e4c | 2010-12-01 08:53:58 +0000 | [diff] [blame] | 998 | UndefElts.setBit(i); |
Chris Lattner | 6705883 | 2012-01-25 06:48:06 +0000 | [diff] [blame] | 999 | continue; |
| 1000 | } |
Craig Topper | 4c94775 | 2012-12-22 18:09:02 +0000 | [diff] [blame] | 1001 | |
Chris Lattner | 6705883 | 2012-01-25 06:48:06 +0000 | [diff] [blame] | 1002 | Constant *Elt = C->getAggregateElement(i); |
Craig Topper | f40110f | 2014-04-25 05:29:35 +0000 | [diff] [blame] | 1003 | if (!Elt) return nullptr; |
Craig Topper | 4c94775 | 2012-12-22 18:09:02 +0000 | [diff] [blame] | 1004 | |
Chris Lattner | 6705883 | 2012-01-25 06:48:06 +0000 | [diff] [blame] | 1005 | if (isa<UndefValue>(Elt)) { // Already undef. |
Chris Lattner | 7e04491 | 2010-01-04 07:17:19 +0000 | [diff] [blame] | 1006 | Elts.push_back(Undef); |
Jay Foad | 25a5e4c | 2010-12-01 08:53:58 +0000 | [diff] [blame] | 1007 | UndefElts.setBit(i); |
Chris Lattner | 7e04491 | 2010-01-04 07:17:19 +0000 | [diff] [blame] | 1008 | } else { // Otherwise, defined. |
Chris Lattner | 6705883 | 2012-01-25 06:48:06 +0000 | [diff] [blame] | 1009 | Elts.push_back(Elt); |
Chris Lattner | 7e04491 | 2010-01-04 07:17:19 +0000 | [diff] [blame] | 1010 | } |
Chris Lattner | 6705883 | 2012-01-25 06:48:06 +0000 | [diff] [blame] | 1011 | } |
Craig Topper | 4c94775 | 2012-12-22 18:09:02 +0000 | [diff] [blame] | 1012 | |
Chris Lattner | 7e04491 | 2010-01-04 07:17:19 +0000 | [diff] [blame] | 1013 | // If we changed the constant, return it. |
Chris Lattner | 47a86bd | 2012-01-25 06:02:56 +0000 | [diff] [blame] | 1014 | Constant *NewCV = ConstantVector::get(Elts); |
Craig Topper | f40110f | 2014-04-25 05:29:35 +0000 | [diff] [blame] | 1015 | return NewCV != C ? NewCV : nullptr; |
Chris Lattner | 7e04491 | 2010-01-04 07:17:19 +0000 | [diff] [blame] | 1016 | } |
Craig Topper | 4c94775 | 2012-12-22 18:09:02 +0000 | [diff] [blame] | 1017 | |
Chris Lattner | 7e04491 | 2010-01-04 07:17:19 +0000 | [diff] [blame] | 1018 | // Limit search depth. |
| 1019 | if (Depth == 10) |
Craig Topper | f40110f | 2014-04-25 05:29:35 +0000 | [diff] [blame] | 1020 | return nullptr; |
Chris Lattner | 7e04491 | 2010-01-04 07:17:19 +0000 | [diff] [blame] | 1021 | |
Stuart Hastings | 5bd18b6 | 2011-05-17 22:13:31 +0000 | [diff] [blame] | 1022 | // If multiple users are using the root value, proceed with |
Chris Lattner | 7e04491 | 2010-01-04 07:17:19 +0000 | [diff] [blame] | 1023 | // simplification conservatively assuming that all elements |
| 1024 | // are needed. |
| 1025 | if (!V->hasOneUse()) { |
| 1026 | // Quit if we find multiple users of a non-root value though. |
| 1027 | // They'll be handled when it's their turn to be visited by |
| 1028 | // the main instcombine process. |
| 1029 | if (Depth != 0) |
| 1030 | // TODO: Just compute the UndefElts information recursively. |
Craig Topper | f40110f | 2014-04-25 05:29:35 +0000 | [diff] [blame] | 1031 | return nullptr; |
Chris Lattner | 7e04491 | 2010-01-04 07:17:19 +0000 | [diff] [blame] | 1032 | |
| 1033 | // Conservatively assume that all elements are needed. |
| 1034 | DemandedElts = EltMask; |
| 1035 | } |
Craig Topper | 4c94775 | 2012-12-22 18:09:02 +0000 | [diff] [blame] | 1036 | |
Chris Lattner | 7e04491 | 2010-01-04 07:17:19 +0000 | [diff] [blame] | 1037 | Instruction *I = dyn_cast<Instruction>(V); |
Craig Topper | f40110f | 2014-04-25 05:29:35 +0000 | [diff] [blame] | 1038 | if (!I) return nullptr; // Only analyze instructions. |
Craig Topper | 4c94775 | 2012-12-22 18:09:02 +0000 | [diff] [blame] | 1039 | |
Chris Lattner | 7e04491 | 2010-01-04 07:17:19 +0000 | [diff] [blame] | 1040 | bool MadeChange = false; |
| 1041 | APInt UndefElts2(VWidth, 0); |
| 1042 | Value *TmpV; |
| 1043 | switch (I->getOpcode()) { |
| 1044 | default: break; |
Craig Topper | 4c94775 | 2012-12-22 18:09:02 +0000 | [diff] [blame] | 1045 | |
Chris Lattner | 7e04491 | 2010-01-04 07:17:19 +0000 | [diff] [blame] | 1046 | case Instruction::InsertElement: { |
| 1047 | // If this is a variable index, we don't know which element it overwrites. |
| 1048 | // demand exactly the same input as we produce. |
| 1049 | ConstantInt *Idx = dyn_cast<ConstantInt>(I->getOperand(2)); |
Craig Topper | f40110f | 2014-04-25 05:29:35 +0000 | [diff] [blame] | 1050 | if (!Idx) { |
Chris Lattner | 7e04491 | 2010-01-04 07:17:19 +0000 | [diff] [blame] | 1051 | // Note that we can't propagate undef elt info, because we don't know |
| 1052 | // which elt is getting updated. |
| 1053 | TmpV = SimplifyDemandedVectorElts(I->getOperand(0), DemandedElts, |
| 1054 | UndefElts2, Depth+1); |
| 1055 | if (TmpV) { I->setOperand(0, TmpV); MadeChange = true; } |
| 1056 | break; |
| 1057 | } |
Craig Topper | 4c94775 | 2012-12-22 18:09:02 +0000 | [diff] [blame] | 1058 | |
Chris Lattner | 7e04491 | 2010-01-04 07:17:19 +0000 | [diff] [blame] | 1059 | // If this is inserting an element that isn't demanded, remove this |
| 1060 | // insertelement. |
| 1061 | unsigned IdxNo = Idx->getZExtValue(); |
| 1062 | if (IdxNo >= VWidth || !DemandedElts[IdxNo]) { |
| 1063 | Worklist.Add(I); |
| 1064 | return I->getOperand(0); |
| 1065 | } |
Craig Topper | 4c94775 | 2012-12-22 18:09:02 +0000 | [diff] [blame] | 1066 | |
Chris Lattner | 7e04491 | 2010-01-04 07:17:19 +0000 | [diff] [blame] | 1067 | // Otherwise, the element inserted overwrites whatever was there, so the |
| 1068 | // input demanded set is simpler than the output set. |
| 1069 | APInt DemandedElts2 = DemandedElts; |
Jay Foad | 25a5e4c | 2010-12-01 08:53:58 +0000 | [diff] [blame] | 1070 | DemandedElts2.clearBit(IdxNo); |
Chris Lattner | 7e04491 | 2010-01-04 07:17:19 +0000 | [diff] [blame] | 1071 | TmpV = SimplifyDemandedVectorElts(I->getOperand(0), DemandedElts2, |
| 1072 | UndefElts, Depth+1); |
| 1073 | if (TmpV) { I->setOperand(0, TmpV); MadeChange = true; } |
| 1074 | |
| 1075 | // The inserted element is defined. |
Jay Foad | 25a5e4c | 2010-12-01 08:53:58 +0000 | [diff] [blame] | 1076 | UndefElts.clearBit(IdxNo); |
Chris Lattner | 7e04491 | 2010-01-04 07:17:19 +0000 | [diff] [blame] | 1077 | break; |
| 1078 | } |
| 1079 | case Instruction::ShuffleVector: { |
| 1080 | ShuffleVectorInst *Shuffle = cast<ShuffleVectorInst>(I); |
| 1081 | uint64_t LHSVWidth = |
| 1082 | cast<VectorType>(Shuffle->getOperand(0)->getType())->getNumElements(); |
| 1083 | APInt LeftDemanded(LHSVWidth, 0), RightDemanded(LHSVWidth, 0); |
| 1084 | for (unsigned i = 0; i < VWidth; i++) { |
| 1085 | if (DemandedElts[i]) { |
| 1086 | unsigned MaskVal = Shuffle->getMaskValue(i); |
| 1087 | if (MaskVal != -1u) { |
| 1088 | assert(MaskVal < LHSVWidth * 2 && |
| 1089 | "shufflevector mask index out of range!"); |
| 1090 | if (MaskVal < LHSVWidth) |
Jay Foad | 25a5e4c | 2010-12-01 08:53:58 +0000 | [diff] [blame] | 1091 | LeftDemanded.setBit(MaskVal); |
Chris Lattner | 7e04491 | 2010-01-04 07:17:19 +0000 | [diff] [blame] | 1092 | else |
Jay Foad | 25a5e4c | 2010-12-01 08:53:58 +0000 | [diff] [blame] | 1093 | RightDemanded.setBit(MaskVal - LHSVWidth); |
Chris Lattner | 7e04491 | 2010-01-04 07:17:19 +0000 | [diff] [blame] | 1094 | } |
| 1095 | } |
| 1096 | } |
| 1097 | |
| 1098 | APInt UndefElts4(LHSVWidth, 0); |
| 1099 | TmpV = SimplifyDemandedVectorElts(I->getOperand(0), LeftDemanded, |
| 1100 | UndefElts4, Depth+1); |
| 1101 | if (TmpV) { I->setOperand(0, TmpV); MadeChange = true; } |
| 1102 | |
| 1103 | APInt UndefElts3(LHSVWidth, 0); |
| 1104 | TmpV = SimplifyDemandedVectorElts(I->getOperand(1), RightDemanded, |
| 1105 | UndefElts3, Depth+1); |
| 1106 | if (TmpV) { I->setOperand(1, TmpV); MadeChange = true; } |
| 1107 | |
| 1108 | bool NewUndefElts = false; |
| 1109 | for (unsigned i = 0; i < VWidth; i++) { |
| 1110 | unsigned MaskVal = Shuffle->getMaskValue(i); |
| 1111 | if (MaskVal == -1u) { |
Jay Foad | 25a5e4c | 2010-12-01 08:53:58 +0000 | [diff] [blame] | 1112 | UndefElts.setBit(i); |
Eli Friedman | 888bea0 | 2011-09-15 01:14:29 +0000 | [diff] [blame] | 1113 | } else if (!DemandedElts[i]) { |
| 1114 | NewUndefElts = true; |
| 1115 | UndefElts.setBit(i); |
Chris Lattner | 7e04491 | 2010-01-04 07:17:19 +0000 | [diff] [blame] | 1116 | } else if (MaskVal < LHSVWidth) { |
| 1117 | if (UndefElts4[MaskVal]) { |
| 1118 | NewUndefElts = true; |
Jay Foad | 25a5e4c | 2010-12-01 08:53:58 +0000 | [diff] [blame] | 1119 | UndefElts.setBit(i); |
Chris Lattner | 7e04491 | 2010-01-04 07:17:19 +0000 | [diff] [blame] | 1120 | } |
| 1121 | } else { |
| 1122 | if (UndefElts3[MaskVal - LHSVWidth]) { |
| 1123 | NewUndefElts = true; |
Jay Foad | 25a5e4c | 2010-12-01 08:53:58 +0000 | [diff] [blame] | 1124 | UndefElts.setBit(i); |
Chris Lattner | 7e04491 | 2010-01-04 07:17:19 +0000 | [diff] [blame] | 1125 | } |
| 1126 | } |
| 1127 | } |
| 1128 | |
| 1129 | if (NewUndefElts) { |
| 1130 | // Add additional discovered undefs. |
Chris Lattner | 0256be9 | 2012-01-27 03:08:05 +0000 | [diff] [blame] | 1131 | SmallVector<Constant*, 16> Elts; |
Chris Lattner | 7e04491 | 2010-01-04 07:17:19 +0000 | [diff] [blame] | 1132 | for (unsigned i = 0; i < VWidth; ++i) { |
| 1133 | if (UndefElts[i]) |
| 1134 | Elts.push_back(UndefValue::get(Type::getInt32Ty(I->getContext()))); |
| 1135 | else |
| 1136 | Elts.push_back(ConstantInt::get(Type::getInt32Ty(I->getContext()), |
| 1137 | Shuffle->getMaskValue(i))); |
| 1138 | } |
| 1139 | I->setOperand(2, ConstantVector::get(Elts)); |
| 1140 | MadeChange = true; |
| 1141 | } |
| 1142 | break; |
| 1143 | } |
Pete Cooper | abc13af | 2012-07-26 23:10:24 +0000 | [diff] [blame] | 1144 | case Instruction::Select: { |
| 1145 | APInt LeftDemanded(DemandedElts), RightDemanded(DemandedElts); |
| 1146 | if (ConstantVector* CV = dyn_cast<ConstantVector>(I->getOperand(0))) { |
| 1147 | for (unsigned i = 0; i < VWidth; i++) { |
| 1148 | if (CV->getAggregateElement(i)->isNullValue()) |
| 1149 | LeftDemanded.clearBit(i); |
| 1150 | else |
| 1151 | RightDemanded.clearBit(i); |
| 1152 | } |
| 1153 | } |
| 1154 | |
| 1155 | TmpV = SimplifyDemandedVectorElts(I->getOperand(1), LeftDemanded, |
| 1156 | UndefElts, Depth+1); |
| 1157 | if (TmpV) { I->setOperand(1, TmpV); MadeChange = true; } |
| 1158 | |
| 1159 | TmpV = SimplifyDemandedVectorElts(I->getOperand(2), RightDemanded, |
| 1160 | UndefElts2, Depth+1); |
| 1161 | if (TmpV) { I->setOperand(2, TmpV); MadeChange = true; } |
Craig Topper | 4c94775 | 2012-12-22 18:09:02 +0000 | [diff] [blame] | 1162 | |
Pete Cooper | abc13af | 2012-07-26 23:10:24 +0000 | [diff] [blame] | 1163 | // Output elements are undefined if both are undefined. |
| 1164 | UndefElts &= UndefElts2; |
| 1165 | break; |
| 1166 | } |
Chris Lattner | 7e04491 | 2010-01-04 07:17:19 +0000 | [diff] [blame] | 1167 | case Instruction::BitCast: { |
| 1168 | // Vector->vector casts only. |
Chris Lattner | 229907c | 2011-07-18 04:54:35 +0000 | [diff] [blame] | 1169 | VectorType *VTy = dyn_cast<VectorType>(I->getOperand(0)->getType()); |
Chris Lattner | 7e04491 | 2010-01-04 07:17:19 +0000 | [diff] [blame] | 1170 | if (!VTy) break; |
| 1171 | unsigned InVWidth = VTy->getNumElements(); |
| 1172 | APInt InputDemandedElts(InVWidth, 0); |
| 1173 | unsigned Ratio; |
| 1174 | |
| 1175 | if (VWidth == InVWidth) { |
| 1176 | // If we are converting from <4 x i32> -> <4 x f32>, we demand the same |
| 1177 | // elements as are demanded of us. |
| 1178 | Ratio = 1; |
| 1179 | InputDemandedElts = DemandedElts; |
| 1180 | } else if (VWidth > InVWidth) { |
| 1181 | // Untested so far. |
| 1182 | break; |
Craig Topper | 4c94775 | 2012-12-22 18:09:02 +0000 | [diff] [blame] | 1183 | |
Chris Lattner | 7e04491 | 2010-01-04 07:17:19 +0000 | [diff] [blame] | 1184 | // If there are more elements in the result than there are in the source, |
| 1185 | // then an input element is live if any of the corresponding output |
| 1186 | // elements are live. |
| 1187 | Ratio = VWidth/InVWidth; |
| 1188 | for (unsigned OutIdx = 0; OutIdx != VWidth; ++OutIdx) { |
| 1189 | if (DemandedElts[OutIdx]) |
Jay Foad | 25a5e4c | 2010-12-01 08:53:58 +0000 | [diff] [blame] | 1190 | InputDemandedElts.setBit(OutIdx/Ratio); |
Chris Lattner | 7e04491 | 2010-01-04 07:17:19 +0000 | [diff] [blame] | 1191 | } |
| 1192 | } else { |
| 1193 | // Untested so far. |
| 1194 | break; |
Craig Topper | 4c94775 | 2012-12-22 18:09:02 +0000 | [diff] [blame] | 1195 | |
Chris Lattner | 7e04491 | 2010-01-04 07:17:19 +0000 | [diff] [blame] | 1196 | // If there are more elements in the source than there are in the result, |
| 1197 | // then an input element is live if the corresponding output element is |
| 1198 | // live. |
| 1199 | Ratio = InVWidth/VWidth; |
| 1200 | for (unsigned InIdx = 0; InIdx != InVWidth; ++InIdx) |
| 1201 | if (DemandedElts[InIdx/Ratio]) |
Jay Foad | 25a5e4c | 2010-12-01 08:53:58 +0000 | [diff] [blame] | 1202 | InputDemandedElts.setBit(InIdx); |
Chris Lattner | 7e04491 | 2010-01-04 07:17:19 +0000 | [diff] [blame] | 1203 | } |
Craig Topper | 4c94775 | 2012-12-22 18:09:02 +0000 | [diff] [blame] | 1204 | |
Chris Lattner | 7e04491 | 2010-01-04 07:17:19 +0000 | [diff] [blame] | 1205 | // div/rem demand all inputs, because they don't want divide by zero. |
| 1206 | TmpV = SimplifyDemandedVectorElts(I->getOperand(0), InputDemandedElts, |
| 1207 | UndefElts2, Depth+1); |
| 1208 | if (TmpV) { |
| 1209 | I->setOperand(0, TmpV); |
| 1210 | MadeChange = true; |
| 1211 | } |
Craig Topper | 4c94775 | 2012-12-22 18:09:02 +0000 | [diff] [blame] | 1212 | |
Chris Lattner | 7e04491 | 2010-01-04 07:17:19 +0000 | [diff] [blame] | 1213 | UndefElts = UndefElts2; |
| 1214 | if (VWidth > InVWidth) { |
| 1215 | llvm_unreachable("Unimp"); |
| 1216 | // If there are more elements in the result than there are in the source, |
| 1217 | // then an output element is undef if the corresponding input element is |
| 1218 | // undef. |
| 1219 | for (unsigned OutIdx = 0; OutIdx != VWidth; ++OutIdx) |
| 1220 | if (UndefElts2[OutIdx/Ratio]) |
Jay Foad | 25a5e4c | 2010-12-01 08:53:58 +0000 | [diff] [blame] | 1221 | UndefElts.setBit(OutIdx); |
Chris Lattner | 7e04491 | 2010-01-04 07:17:19 +0000 | [diff] [blame] | 1222 | } else if (VWidth < InVWidth) { |
| 1223 | llvm_unreachable("Unimp"); |
| 1224 | // If there are more elements in the source than there are in the result, |
| 1225 | // then a result element is undef if all of the corresponding input |
| 1226 | // elements are undef. |
| 1227 | UndefElts = ~0ULL >> (64-VWidth); // Start out all undef. |
| 1228 | for (unsigned InIdx = 0; InIdx != InVWidth; ++InIdx) |
| 1229 | if (!UndefElts2[InIdx]) // Not undef? |
Jay Foad | 25a5e4c | 2010-12-01 08:53:58 +0000 | [diff] [blame] | 1230 | UndefElts.clearBit(InIdx/Ratio); // Clear undef bit. |
Chris Lattner | 7e04491 | 2010-01-04 07:17:19 +0000 | [diff] [blame] | 1231 | } |
| 1232 | break; |
| 1233 | } |
| 1234 | case Instruction::And: |
| 1235 | case Instruction::Or: |
| 1236 | case Instruction::Xor: |
| 1237 | case Instruction::Add: |
| 1238 | case Instruction::Sub: |
| 1239 | case Instruction::Mul: |
| 1240 | // div/rem demand all inputs, because they don't want divide by zero. |
| 1241 | TmpV = SimplifyDemandedVectorElts(I->getOperand(0), DemandedElts, |
| 1242 | UndefElts, Depth+1); |
| 1243 | if (TmpV) { I->setOperand(0, TmpV); MadeChange = true; } |
| 1244 | TmpV = SimplifyDemandedVectorElts(I->getOperand(1), DemandedElts, |
| 1245 | UndefElts2, Depth+1); |
| 1246 | if (TmpV) { I->setOperand(1, TmpV); MadeChange = true; } |
Craig Topper | 4c94775 | 2012-12-22 18:09:02 +0000 | [diff] [blame] | 1247 | |
Chris Lattner | 7e04491 | 2010-01-04 07:17:19 +0000 | [diff] [blame] | 1248 | // Output elements are undefined if both are undefined. Consider things |
| 1249 | // like undef&0. The result is known zero, not undef. |
| 1250 | UndefElts &= UndefElts2; |
| 1251 | break; |
Pete Cooper | e807e45 | 2012-07-26 22:37:04 +0000 | [diff] [blame] | 1252 | case Instruction::FPTrunc: |
| 1253 | case Instruction::FPExt: |
| 1254 | TmpV = SimplifyDemandedVectorElts(I->getOperand(0), DemandedElts, |
| 1255 | UndefElts, Depth+1); |
| 1256 | if (TmpV) { I->setOperand(0, TmpV); MadeChange = true; } |
| 1257 | break; |
Craig Topper | 4c94775 | 2012-12-22 18:09:02 +0000 | [diff] [blame] | 1258 | |
Chris Lattner | 7e04491 | 2010-01-04 07:17:19 +0000 | [diff] [blame] | 1259 | case Instruction::Call: { |
| 1260 | IntrinsicInst *II = dyn_cast<IntrinsicInst>(I); |
| 1261 | if (!II) break; |
| 1262 | switch (II->getIntrinsicID()) { |
| 1263 | default: break; |
Craig Topper | 4c94775 | 2012-12-22 18:09:02 +0000 | [diff] [blame] | 1264 | |
Chris Lattner | 7e04491 | 2010-01-04 07:17:19 +0000 | [diff] [blame] | 1265 | // Binary vector operations that work column-wise. A dest element is a |
| 1266 | // function of the corresponding input elements from the two inputs. |
| 1267 | case Intrinsic::x86_sse_sub_ss: |
| 1268 | case Intrinsic::x86_sse_mul_ss: |
| 1269 | case Intrinsic::x86_sse_min_ss: |
| 1270 | case Intrinsic::x86_sse_max_ss: |
| 1271 | case Intrinsic::x86_sse2_sub_sd: |
| 1272 | case Intrinsic::x86_sse2_mul_sd: |
| 1273 | case Intrinsic::x86_sse2_min_sd: |
| 1274 | case Intrinsic::x86_sse2_max_sd: |
Gabor Greif | e23efee | 2010-06-28 16:45:00 +0000 | [diff] [blame] | 1275 | TmpV = SimplifyDemandedVectorElts(II->getArgOperand(0), DemandedElts, |
Eric Christopher | 7258dcd | 2010-04-16 23:37:20 +0000 | [diff] [blame] | 1276 | UndefElts, Depth+1); |
Gabor Greif | e23efee | 2010-06-28 16:45:00 +0000 | [diff] [blame] | 1277 | if (TmpV) { II->setArgOperand(0, TmpV); MadeChange = true; } |
| 1278 | TmpV = SimplifyDemandedVectorElts(II->getArgOperand(1), DemandedElts, |
Eric Christopher | 7258dcd | 2010-04-16 23:37:20 +0000 | [diff] [blame] | 1279 | UndefElts2, Depth+1); |
Gabor Greif | e23efee | 2010-06-28 16:45:00 +0000 | [diff] [blame] | 1280 | if (TmpV) { II->setArgOperand(1, TmpV); MadeChange = true; } |
Chris Lattner | 7e04491 | 2010-01-04 07:17:19 +0000 | [diff] [blame] | 1281 | |
| 1282 | // If only the low elt is demanded and this is a scalarizable intrinsic, |
| 1283 | // scalarize it now. |
| 1284 | if (DemandedElts == 1) { |
| 1285 | switch (II->getIntrinsicID()) { |
| 1286 | default: break; |
| 1287 | case Intrinsic::x86_sse_sub_ss: |
| 1288 | case Intrinsic::x86_sse_mul_ss: |
| 1289 | case Intrinsic::x86_sse2_sub_sd: |
| 1290 | case Intrinsic::x86_sse2_mul_sd: |
| 1291 | // TODO: Lower MIN/MAX/ABS/etc |
Gabor Greif | 7943017 | 2010-06-24 12:35:13 +0000 | [diff] [blame] | 1292 | Value *LHS = II->getArgOperand(0); |
| 1293 | Value *RHS = II->getArgOperand(1); |
Chris Lattner | 7e04491 | 2010-01-04 07:17:19 +0000 | [diff] [blame] | 1294 | // Extract the element as scalars. |
Craig Topper | 4c94775 | 2012-12-22 18:09:02 +0000 | [diff] [blame] | 1295 | LHS = InsertNewInstWith(ExtractElementInst::Create(LHS, |
Chris Lattner | 7e04491 | 2010-01-04 07:17:19 +0000 | [diff] [blame] | 1296 | ConstantInt::get(Type::getInt32Ty(I->getContext()), 0U)), *II); |
Eli Friedman | 6efb64e | 2011-05-19 01:20:42 +0000 | [diff] [blame] | 1297 | RHS = InsertNewInstWith(ExtractElementInst::Create(RHS, |
Chris Lattner | 7e04491 | 2010-01-04 07:17:19 +0000 | [diff] [blame] | 1298 | ConstantInt::get(Type::getInt32Ty(I->getContext()), 0U)), *II); |
Craig Topper | 4c94775 | 2012-12-22 18:09:02 +0000 | [diff] [blame] | 1299 | |
Chris Lattner | 7e04491 | 2010-01-04 07:17:19 +0000 | [diff] [blame] | 1300 | switch (II->getIntrinsicID()) { |
| 1301 | default: llvm_unreachable("Case stmts out of sync!"); |
| 1302 | case Intrinsic::x86_sse_sub_ss: |
| 1303 | case Intrinsic::x86_sse2_sub_sd: |
Eli Friedman | 6efb64e | 2011-05-19 01:20:42 +0000 | [diff] [blame] | 1304 | TmpV = InsertNewInstWith(BinaryOperator::CreateFSub(LHS, RHS, |
Chris Lattner | 7e04491 | 2010-01-04 07:17:19 +0000 | [diff] [blame] | 1305 | II->getName()), *II); |
| 1306 | break; |
| 1307 | case Intrinsic::x86_sse_mul_ss: |
| 1308 | case Intrinsic::x86_sse2_mul_sd: |
Eli Friedman | 6efb64e | 2011-05-19 01:20:42 +0000 | [diff] [blame] | 1309 | TmpV = InsertNewInstWith(BinaryOperator::CreateFMul(LHS, RHS, |
Chris Lattner | 7e04491 | 2010-01-04 07:17:19 +0000 | [diff] [blame] | 1310 | II->getName()), *II); |
| 1311 | break; |
| 1312 | } |
Craig Topper | 4c94775 | 2012-12-22 18:09:02 +0000 | [diff] [blame] | 1313 | |
Chris Lattner | 7e04491 | 2010-01-04 07:17:19 +0000 | [diff] [blame] | 1314 | Instruction *New = |
| 1315 | InsertElementInst::Create( |
| 1316 | UndefValue::get(II->getType()), TmpV, |
| 1317 | ConstantInt::get(Type::getInt32Ty(I->getContext()), 0U, false), |
| 1318 | II->getName()); |
Eli Friedman | 6efb64e | 2011-05-19 01:20:42 +0000 | [diff] [blame] | 1319 | InsertNewInstWith(New, *II); |
Chris Lattner | 7e04491 | 2010-01-04 07:17:19 +0000 | [diff] [blame] | 1320 | return New; |
Craig Topper | 4c94775 | 2012-12-22 18:09:02 +0000 | [diff] [blame] | 1321 | } |
Chris Lattner | 7e04491 | 2010-01-04 07:17:19 +0000 | [diff] [blame] | 1322 | } |
Craig Topper | 4c94775 | 2012-12-22 18:09:02 +0000 | [diff] [blame] | 1323 | |
Chris Lattner | 7e04491 | 2010-01-04 07:17:19 +0000 | [diff] [blame] | 1324 | // Output elements are undefined if both are undefined. Consider things |
| 1325 | // like undef&0. The result is known zero, not undef. |
| 1326 | UndefElts &= UndefElts2; |
| 1327 | break; |
| 1328 | } |
| 1329 | break; |
| 1330 | } |
| 1331 | } |
Craig Topper | f40110f | 2014-04-25 05:29:35 +0000 | [diff] [blame] | 1332 | return MadeChange ? I : nullptr; |
Chris Lattner | 7e04491 | 2010-01-04 07:17:19 +0000 | [diff] [blame] | 1333 | } |