Chris Lattner | d1e693f | 2002-09-08 18:59:35 +0000 | [diff] [blame] | 1 | //===-- BasicBlock.cpp - Implement BasicBlock related methods -------------===// |
Misha Brukman | fd93908 | 2005-04-21 23:48:37 +0000 | [diff] [blame] | 2 | // |
John Criswell | b576c94 | 2003-10-20 19:43:21 +0000 | [diff] [blame] | 3 | // The LLVM Compiler Infrastructure |
| 4 | // |
Chris Lattner | 4ee451d | 2007-12-29 20:36:04 +0000 | [diff] [blame^] | 5 | // This file is distributed under the University of Illinois Open Source |
| 6 | // License. See LICENSE.TXT for details. |
Misha Brukman | fd93908 | 2005-04-21 23:48:37 +0000 | [diff] [blame] | 7 | // |
John Criswell | b576c94 | 2003-10-20 19:43:21 +0000 | [diff] [blame] | 8 | //===----------------------------------------------------------------------===// |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 9 | // |
Chris Lattner | b7653df | 2002-04-08 22:03:57 +0000 | [diff] [blame] | 10 | // This file implements the BasicBlock class for the VMCore library. |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 11 | // |
| 12 | //===----------------------------------------------------------------------===// |
| 13 | |
Chris Lattner | 7e70829 | 2002-06-25 16:13:24 +0000 | [diff] [blame] | 14 | #include "llvm/BasicBlock.h" |
Chris Lattner | 3464547 | 2005-04-12 18:52:14 +0000 | [diff] [blame] | 15 | #include "llvm/Constants.h" |
Misha Brukman | 4433629 | 2004-07-29 16:53:53 +0000 | [diff] [blame] | 16 | #include "llvm/Instructions.h" |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 17 | #include "llvm/Type.h" |
Chris Lattner | 455889a | 2002-02-12 22:39:50 +0000 | [diff] [blame] | 18 | #include "llvm/Support/CFG.h" |
Reid Spencer | 551ccae | 2004-09-01 22:55:40 +0000 | [diff] [blame] | 19 | #include "llvm/Support/LeakDetector.h" |
Chris Lattner | a4f0b3a | 2006-08-27 12:54:02 +0000 | [diff] [blame] | 20 | #include "llvm/Support/Compiler.h" |
Chris Lattner | 7e70829 | 2002-06-25 16:13:24 +0000 | [diff] [blame] | 21 | #include "SymbolTableListTraitsImpl.h" |
| 22 | #include <algorithm> |
Chris Lattner | 108e4ab | 2003-11-21 16:52:05 +0000 | [diff] [blame] | 23 | using namespace llvm; |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 24 | |
Chris Lattner | 17fcdd5 | 2007-04-17 03:26:42 +0000 | [diff] [blame] | 25 | inline ValueSymbolTable * |
| 26 | ilist_traits<Instruction>::getSymTab(BasicBlock *BB) { |
| 27 | if (BB) |
| 28 | if (Function *F = BB->getParent()) |
| 29 | return &F->getValueSymbolTable(); |
| 30 | return 0; |
| 31 | } |
| 32 | |
Gordon Henriksen | afba8fe | 2007-12-10 02:14:30 +0000 | [diff] [blame] | 33 | |
| 34 | namespace { |
| 35 | /// DummyInst - An instance of this class is used to mark the end of the |
| 36 | /// instruction list. This is not a real instruction. |
| 37 | struct VISIBILITY_HIDDEN DummyInst : public Instruction { |
| 38 | DummyInst() : Instruction(Type::VoidTy, OtherOpsEnd, 0, 0) { |
| 39 | // This should not be garbage monitored. |
| 40 | LeakDetector::removeGarbageObject(this); |
| 41 | } |
| 42 | |
| 43 | Instruction *clone() const { |
| 44 | assert(0 && "Cannot clone EOL");abort(); |
| 45 | return 0; |
| 46 | } |
| 47 | const char *getOpcodeName() const { return "*end-of-list-inst*"; } |
| 48 | |
| 49 | // Methods for support type inquiry through isa, cast, and dyn_cast... |
| 50 | static inline bool classof(const DummyInst *) { return true; } |
| 51 | static inline bool classof(const Instruction *I) { |
| 52 | return I->getOpcode() == OtherOpsEnd; |
| 53 | } |
| 54 | static inline bool classof(const Value *V) { |
| 55 | return isa<Instruction>(V) && classof(cast<Instruction>(V)); |
| 56 | } |
| 57 | }; |
Chris Lattner | 108e4ab | 2003-11-21 16:52:05 +0000 | [diff] [blame] | 58 | } |
Chris Lattner | 7e70829 | 2002-06-25 16:13:24 +0000 | [diff] [blame] | 59 | |
Chris Lattner | bca8144 | 2005-01-30 00:09:23 +0000 | [diff] [blame] | 60 | Instruction *ilist_traits<Instruction>::createSentinel() { |
Chris Lattner | 7e70829 | 2002-06-25 16:13:24 +0000 | [diff] [blame] | 61 | return new DummyInst(); |
| 62 | } |
| 63 | iplist<Instruction> &ilist_traits<Instruction>::getList(BasicBlock *BB) { |
| 64 | return BB->getInstList(); |
| 65 | } |
| 66 | |
| 67 | // Explicit instantiation of SymbolTableListTraits since some of the methods |
| 68 | // are not in the public header file... |
Chris Lattner | 17fcdd5 | 2007-04-17 03:26:42 +0000 | [diff] [blame] | 69 | template class SymbolTableListTraits<Instruction, BasicBlock>; |
Chris Lattner | 7e70829 | 2002-06-25 16:13:24 +0000 | [diff] [blame] | 70 | |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 71 | |
Chris Lattner | 17fcdd5 | 2007-04-17 03:26:42 +0000 | [diff] [blame] | 72 | BasicBlock::BasicBlock(const std::string &Name, Function *NewParent, |
Chris Lattner | 4f05611 | 2004-02-04 03:57:50 +0000 | [diff] [blame] | 73 | BasicBlock *InsertBefore) |
Chris Lattner | 17fcdd5 | 2007-04-17 03:26:42 +0000 | [diff] [blame] | 74 | : Value(Type::LabelTy, Value::BasicBlockVal), Parent(0) { |
Chris Lattner | 0a1a874 | 2002-09-26 05:03:22 +0000 | [diff] [blame] | 75 | |
| 76 | // Make sure that we get added to a function |
| 77 | LeakDetector::addGarbageObject(this); |
| 78 | |
| 79 | if (InsertBefore) { |
Chris Lattner | 17fcdd5 | 2007-04-17 03:26:42 +0000 | [diff] [blame] | 80 | assert(NewParent && |
Chris Lattner | 4f05611 | 2004-02-04 03:57:50 +0000 | [diff] [blame] | 81 | "Cannot insert block before another block with no function!"); |
Chris Lattner | 17fcdd5 | 2007-04-17 03:26:42 +0000 | [diff] [blame] | 82 | NewParent->getBasicBlockList().insert(InsertBefore, this); |
| 83 | } else if (NewParent) { |
| 84 | NewParent->getBasicBlockList().push_back(this); |
Chris Lattner | 0a1a874 | 2002-09-26 05:03:22 +0000 | [diff] [blame] | 85 | } |
Chris Lattner | dec628e | 2007-02-12 05:18:08 +0000 | [diff] [blame] | 86 | |
| 87 | setName(Name); |
Chris Lattner | 0a1a874 | 2002-09-26 05:03:22 +0000 | [diff] [blame] | 88 | } |
| 89 | |
| 90 | |
Gordon Henriksen | afba8fe | 2007-12-10 02:14:30 +0000 | [diff] [blame] | 91 | BasicBlock::~BasicBlock() { |
| 92 | assert(getParent() == 0 && "BasicBlock still linked into the program!"); |
| 93 | dropAllReferences(); |
| 94 | InstList.clear(); |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 95 | } |
| 96 | |
Chris Lattner | bded132 | 2002-09-06 21:33:15 +0000 | [diff] [blame] | 97 | void BasicBlock::setParent(Function *parent) { |
Chris Lattner | d1e693f | 2002-09-08 18:59:35 +0000 | [diff] [blame] | 98 | if (getParent()) |
| 99 | LeakDetector::addGarbageObject(this); |
| 100 | |
Chris Lattner | 17fcdd5 | 2007-04-17 03:26:42 +0000 | [diff] [blame] | 101 | // Set Parent=parent, updating instruction symtab entries as appropriate. |
| 102 | InstList.setSymTabObject(&Parent, parent); |
Chris Lattner | d1e693f | 2002-09-08 18:59:35 +0000 | [diff] [blame] | 103 | |
| 104 | if (getParent()) |
| 105 | LeakDetector::removeGarbageObject(this); |
Chris Lattner | bded132 | 2002-09-06 21:33:15 +0000 | [diff] [blame] | 106 | } |
| 107 | |
Chris Lattner | 4b83380 | 2004-10-11 22:21:39 +0000 | [diff] [blame] | 108 | void BasicBlock::removeFromParent() { |
| 109 | getParent()->getBasicBlockList().remove(this); |
| 110 | } |
| 111 | |
| 112 | void BasicBlock::eraseFromParent() { |
| 113 | getParent()->getBasicBlockList().erase(this); |
| 114 | } |
| 115 | |
Chris Lattner | a71965b | 2006-09-23 04:03:45 +0000 | [diff] [blame] | 116 | /// moveBefore - Unlink this basic block from its current function and |
| 117 | /// insert it into the function that MovePos lives in, right before MovePos. |
Chris Lattner | 6a13aed | 2005-08-12 22:14:06 +0000 | [diff] [blame] | 118 | void BasicBlock::moveBefore(BasicBlock *MovePos) { |
| 119 | MovePos->getParent()->getBasicBlockList().splice(MovePos, |
| 120 | getParent()->getBasicBlockList(), this); |
| 121 | } |
| 122 | |
Chris Lattner | a71965b | 2006-09-23 04:03:45 +0000 | [diff] [blame] | 123 | /// moveAfter - Unlink this basic block from its current function and |
| 124 | /// insert it into the function that MovePos lives in, right after MovePos. |
| 125 | void BasicBlock::moveAfter(BasicBlock *MovePos) { |
| 126 | Function::iterator I = MovePos; |
| 127 | MovePos->getParent()->getBasicBlockList().splice(++I, |
| 128 | getParent()->getBasicBlockList(), this); |
| 129 | } |
| 130 | |
Chris Lattner | 4b83380 | 2004-10-11 22:21:39 +0000 | [diff] [blame] | 131 | |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 132 | TerminatorInst *BasicBlock::getTerminator() { |
| 133 | if (InstList.empty()) return 0; |
Chris Lattner | 7e70829 | 2002-06-25 16:13:24 +0000 | [diff] [blame] | 134 | return dyn_cast<TerminatorInst>(&InstList.back()); |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 135 | } |
| 136 | |
Dan Gohman | 50cdabc | 2007-11-19 20:46:23 +0000 | [diff] [blame] | 137 | const TerminatorInst *BasicBlock::getTerminator() const { |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 138 | if (InstList.empty()) return 0; |
Chris Lattner | 7e70829 | 2002-06-25 16:13:24 +0000 | [diff] [blame] | 139 | return dyn_cast<TerminatorInst>(&InstList.back()); |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 140 | } |
| 141 | |
Vladimir Prus | dd49dbf | 2006-06-08 15:46:18 +0000 | [diff] [blame] | 142 | Instruction* BasicBlock::getFirstNonPHI() |
| 143 | { |
Vladimir Prus | 28962f3 | 2006-06-08 16:03:13 +0000 | [diff] [blame] | 144 | BasicBlock::iterator i = begin(); |
Vladimir Prus | dd49dbf | 2006-06-08 15:46:18 +0000 | [diff] [blame] | 145 | // All valid basic blocks should have a terminator, |
| 146 | // which is not a PHINode. If we have invalid basic |
| 147 | // block we'll get assert when dereferencing past-the-end |
| 148 | // iterator. |
| 149 | while (isa<PHINode>(i)) ++i; |
| 150 | return &*i; |
| 151 | } |
| 152 | |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 153 | void BasicBlock::dropAllReferences() { |
Chris Lattner | 7e70829 | 2002-06-25 16:13:24 +0000 | [diff] [blame] | 154 | for(iterator I = begin(), E = end(); I != E; ++I) |
| 155 | I->dropAllReferences(); |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 156 | } |
| 157 | |
Chris Lattner | ad993cb | 2005-02-24 02:37:26 +0000 | [diff] [blame] | 158 | /// getSinglePredecessor - If this basic block has a single predecessor block, |
| 159 | /// return the block, otherwise return a null pointer. |
| 160 | BasicBlock *BasicBlock::getSinglePredecessor() { |
| 161 | pred_iterator PI = pred_begin(this), E = pred_end(this); |
| 162 | if (PI == E) return 0; // No preds. |
| 163 | BasicBlock *ThePred = *PI; |
| 164 | ++PI; |
| 165 | return (PI == E) ? ThePred : 0 /*multiple preds*/; |
| 166 | } |
| 167 | |
Chris Lattner | 566f600 | 2005-04-21 16:06:03 +0000 | [diff] [blame] | 168 | /// removePredecessor - This method is used to notify a BasicBlock that the |
| 169 | /// specified Predecessor of the block is no longer able to reach it. This is |
Misha Brukman | fd93908 | 2005-04-21 23:48:37 +0000 | [diff] [blame] | 170 | /// actually not used to update the Predecessor list, but is actually used to |
Chris Lattner | 566f600 | 2005-04-21 16:06:03 +0000 | [diff] [blame] | 171 | /// update the PHI nodes that reside in the block. Note that this should be |
| 172 | /// called while the predecessor still refers to this block. |
| 173 | /// |
Chris Lattner | 3464547 | 2005-04-12 18:52:14 +0000 | [diff] [blame] | 174 | void BasicBlock::removePredecessor(BasicBlock *Pred, |
| 175 | bool DontDeleteUselessPHIs) { |
Chris Lattner | 1f21ef1 | 2005-02-23 16:53:04 +0000 | [diff] [blame] | 176 | assert((hasNUsesOrMore(16)||// Reduce cost of this assertion for complex CFGs. |
Chris Lattner | 35f0aec | 2005-02-23 07:09:08 +0000 | [diff] [blame] | 177 | find(pred_begin(this), pred_end(this), Pred) != pred_end(this)) && |
Jeff Cohen | 9d80930 | 2005-04-23 21:38:35 +0000 | [diff] [blame] | 178 | "removePredecessor: BB is not a predecessor!"); |
Chris Lattner | 35f0aec | 2005-02-23 07:09:08 +0000 | [diff] [blame] | 179 | |
Chris Lattner | f23586c | 2004-12-11 22:10:29 +0000 | [diff] [blame] | 180 | if (InstList.empty()) return; |
Chris Lattner | a9e7781 | 2004-07-06 17:44:17 +0000 | [diff] [blame] | 181 | PHINode *APN = dyn_cast<PHINode>(&front()); |
| 182 | if (!APN) return; // Quick exit. |
Chris Lattner | b47af25 | 2001-06-29 05:25:23 +0000 | [diff] [blame] | 183 | |
| 184 | // If there are exactly two predecessors, then we want to nuke the PHI nodes |
Chris Lattner | a9e7781 | 2004-07-06 17:44:17 +0000 | [diff] [blame] | 185 | // altogether. However, we cannot do this, if this in this case: |
Chris Lattner | 87a09b1 | 2002-05-21 19:52:49 +0000 | [diff] [blame] | 186 | // |
| 187 | // Loop: |
| 188 | // %x = phi [X, Loop] |
| 189 | // %x2 = add %x, 1 ;; This would become %x2 = add %x2, 1 |
| 190 | // br Loop ;; %x2 does not dominate all uses |
| 191 | // |
| 192 | // This is because the PHI node input is actually taken from the predecessor |
Misha Brukman | fd93908 | 2005-04-21 23:48:37 +0000 | [diff] [blame] | 193 | // basic block. The only case this can happen is with a self loop, so we |
Chris Lattner | 87a09b1 | 2002-05-21 19:52:49 +0000 | [diff] [blame] | 194 | // check for this case explicitly now. |
Misha Brukman | fd93908 | 2005-04-21 23:48:37 +0000 | [diff] [blame] | 195 | // |
Chris Lattner | a9e7781 | 2004-07-06 17:44:17 +0000 | [diff] [blame] | 196 | unsigned max_idx = APN->getNumIncomingValues(); |
Chris Lattner | b47af25 | 2001-06-29 05:25:23 +0000 | [diff] [blame] | 197 | assert(max_idx != 0 && "PHI Node in block with 0 predecessors!?!?!"); |
Chris Lattner | 87a09b1 | 2002-05-21 19:52:49 +0000 | [diff] [blame] | 198 | if (max_idx == 2) { |
Chris Lattner | a9e7781 | 2004-07-06 17:44:17 +0000 | [diff] [blame] | 199 | BasicBlock *Other = APN->getIncomingBlock(APN->getIncomingBlock(0) == Pred); |
Chris Lattner | 87a09b1 | 2002-05-21 19:52:49 +0000 | [diff] [blame] | 200 | |
| 201 | // Disable PHI elimination! |
| 202 | if (this == Other) max_idx = 3; |
| 203 | } |
| 204 | |
Chris Lattner | 3464547 | 2005-04-12 18:52:14 +0000 | [diff] [blame] | 205 | // <= Two predecessors BEFORE I remove one? |
| 206 | if (max_idx <= 2 && !DontDeleteUselessPHIs) { |
Chris Lattner | b00c582 | 2001-10-02 03:41:24 +0000 | [diff] [blame] | 207 | // Yup, loop through and nuke the PHI nodes |
Chris Lattner | 7e70829 | 2002-06-25 16:13:24 +0000 | [diff] [blame] | 208 | while (PHINode *PN = dyn_cast<PHINode>(&front())) { |
Chris Lattner | 3464547 | 2005-04-12 18:52:14 +0000 | [diff] [blame] | 209 | // Remove the predecessor first. |
| 210 | PN->removeIncomingValue(Pred, !DontDeleteUselessPHIs); |
Chris Lattner | b47af25 | 2001-06-29 05:25:23 +0000 | [diff] [blame] | 211 | |
| 212 | // If the PHI _HAD_ two uses, replace PHI node with its now *single* value |
Chris Lattner | dee430d | 2002-10-08 21:36:34 +0000 | [diff] [blame] | 213 | if (max_idx == 2) { |
Chris Lattner | 02a78cf | 2003-04-25 23:14:19 +0000 | [diff] [blame] | 214 | if (PN->getOperand(0) != PN) |
| 215 | PN->replaceAllUsesWith(PN->getOperand(0)); |
| 216 | else |
| 217 | // We are left with an infinite loop with no entries: kill the PHI. |
Chris Lattner | 3464547 | 2005-04-12 18:52:14 +0000 | [diff] [blame] | 218 | PN->replaceAllUsesWith(UndefValue::get(PN->getType())); |
Chris Lattner | dee430d | 2002-10-08 21:36:34 +0000 | [diff] [blame] | 219 | getInstList().pop_front(); // Remove the PHI node |
| 220 | } |
| 221 | |
| 222 | // If the PHI node already only had one entry, it got deleted by |
| 223 | // removeIncomingValue. |
Chris Lattner | b47af25 | 2001-06-29 05:25:23 +0000 | [diff] [blame] | 224 | } |
| 225 | } else { |
| 226 | // Okay, now we know that we need to remove predecessor #pred_idx from all |
| 227 | // PHI nodes. Iterate over each PHI node fixing them up |
Chris Lattner | f878218 | 2004-06-05 00:11:27 +0000 | [diff] [blame] | 228 | PHINode *PN; |
Chris Lattner | 80f4d88 | 2005-08-05 15:34:10 +0000 | [diff] [blame] | 229 | for (iterator II = begin(); (PN = dyn_cast<PHINode>(II)); ) { |
| 230 | ++II; |
Chris Lattner | 3464547 | 2005-04-12 18:52:14 +0000 | [diff] [blame] | 231 | PN->removeIncomingValue(Pred, false); |
Nate Begeman | a83ba0f | 2005-08-04 23:24:19 +0000 | [diff] [blame] | 232 | // If all incoming values to the Phi are the same, we can replace the Phi |
| 233 | // with that value. |
Owen Anderson | 90245d4 | 2006-06-14 04:43:14 +0000 | [diff] [blame] | 234 | Value* PNV = 0; |
| 235 | if (!DontDeleteUselessPHIs && (PNV = PN->hasConstantValue())) { |
Chris Lattner | 1325b42 | 2005-08-05 01:02:04 +0000 | [diff] [blame] | 236 | PN->replaceAllUsesWith(PNV); |
| 237 | PN->eraseFromParent(); |
| 238 | } |
Nate Begeman | a83ba0f | 2005-08-04 23:24:19 +0000 | [diff] [blame] | 239 | } |
Chris Lattner | b47af25 | 2001-06-29 05:25:23 +0000 | [diff] [blame] | 240 | } |
| 241 | } |
| 242 | |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 243 | |
Chris Lattner | 0f67dd6 | 2005-04-21 16:04:49 +0000 | [diff] [blame] | 244 | /// splitBasicBlock - This splits a basic block into two at the specified |
| 245 | /// instruction. Note that all instructions BEFORE the specified iterator stay |
Misha Brukman | fd93908 | 2005-04-21 23:48:37 +0000 | [diff] [blame] | 246 | /// as part of the original basic block, an unconditional branch is added to |
Chris Lattner | 0f67dd6 | 2005-04-21 16:04:49 +0000 | [diff] [blame] | 247 | /// the new BB, and the rest of the instructions in the BB are moved to the new |
| 248 | /// BB, including the old terminator. This invalidates the iterator. |
| 249 | /// |
Misha Brukman | fd93908 | 2005-04-21 23:48:37 +0000 | [diff] [blame] | 250 | /// Note that this only works on well formed basic blocks (must have a |
Chris Lattner | 0f67dd6 | 2005-04-21 16:04:49 +0000 | [diff] [blame] | 251 | /// terminator), and 'I' must not be the end of instruction list (which would |
| 252 | /// cause a degenerate basic block to be formed, having a terminator inside of |
Misha Brukman | fd93908 | 2005-04-21 23:48:37 +0000 | [diff] [blame] | 253 | /// the basic block). |
Chris Lattner | 0f67dd6 | 2005-04-21 16:04:49 +0000 | [diff] [blame] | 254 | /// |
Chris Lattner | 4bd4aa5 | 2003-08-24 03:41:39 +0000 | [diff] [blame] | 255 | BasicBlock *BasicBlock::splitBasicBlock(iterator I, const std::string &BBName) { |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 256 | assert(getTerminator() && "Can't use splitBasicBlock on degenerate BB!"); |
Misha Brukman | fd93908 | 2005-04-21 23:48:37 +0000 | [diff] [blame] | 257 | assert(I != InstList.end() && |
Jeff Cohen | 9d80930 | 2005-04-23 21:38:35 +0000 | [diff] [blame] | 258 | "Trying to get me to create degenerate basic block!"); |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 259 | |
Chris Lattner | 4f05611 | 2004-02-04 03:57:50 +0000 | [diff] [blame] | 260 | BasicBlock *New = new BasicBlock(BBName, getParent(), getNext()); |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 261 | |
Chris Lattner | f2c3106 | 2004-02-03 23:11:21 +0000 | [diff] [blame] | 262 | // Move all of the specified instructions from the original basic block into |
| 263 | // the new basic block. |
| 264 | New->getInstList().splice(New->end(), this->getInstList(), I, end()); |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 265 | |
| 266 | // Add a branch instruction to the newly formed basic block. |
Chris Lattner | 108e4ab | 2003-11-21 16:52:05 +0000 | [diff] [blame] | 267 | new BranchInst(New, this); |
Chris Lattner | e8e320d | 2002-02-25 00:35:07 +0000 | [diff] [blame] | 268 | |
| 269 | // Now we must loop through all of the successors of the New block (which |
| 270 | // _were_ the successors of the 'this' block), and update any PHI nodes in |
| 271 | // successors. If there were PHI nodes in the successors, then they need to |
| 272 | // know that incoming branches will be from New, not from Old. |
| 273 | // |
Chris Lattner | 1c9ab51 | 2003-09-24 22:03:22 +0000 | [diff] [blame] | 274 | for (succ_iterator I = succ_begin(New), E = succ_end(New); I != E; ++I) { |
Chris Lattner | e8e320d | 2002-02-25 00:35:07 +0000 | [diff] [blame] | 275 | // Loop over any phi nodes in the basic block, updating the BB field of |
| 276 | // incoming values... |
| 277 | BasicBlock *Successor = *I; |
Chris Lattner | f878218 | 2004-06-05 00:11:27 +0000 | [diff] [blame] | 278 | PHINode *PN; |
Chris Lattner | e8e320d | 2002-02-25 00:35:07 +0000 | [diff] [blame] | 279 | for (BasicBlock::iterator II = Successor->begin(); |
Chris Lattner | 9bf2a92 | 2004-06-05 17:43:52 +0000 | [diff] [blame] | 280 | (PN = dyn_cast<PHINode>(II)); ++II) { |
Chris Lattner | e8e320d | 2002-02-25 00:35:07 +0000 | [diff] [blame] | 281 | int IDX = PN->getBasicBlockIndex(this); |
| 282 | while (IDX != -1) { |
| 283 | PN->setIncomingBlock((unsigned)IDX, New); |
| 284 | IDX = PN->getBasicBlockIndex(this); |
| 285 | } |
| 286 | } |
| 287 | } |
Chris Lattner | 0095054 | 2001-06-06 20:29:01 +0000 | [diff] [blame] | 288 | return New; |
| 289 | } |