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Fix Transforms/LoopUnroll/2007-05-05-UnrollMiscomp.ll and PR1385.

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If we have a LCSSA, only modify the input value if the inval was defined
by an instruction in the loop.  If defined by something before the loop,
it is still valid.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@36784 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Chris Lattner 2007-05-05 18:49:57 +00:00
parent 823572d44d
commit caccc996e2
1 changed files with 17 additions and 18 deletions
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35
lib/Transforms/Scalar/LoopUnroll.cpp
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@ -203,7 +203,8 @@ bool LoopUnroll::runOnLoop(Loop *L, LPPassManager &LPM) {
// For the first iteration of the loop, we should use the precloned values for
// PHI nodes. Insert associations now.
DenseMap<const Value*, Value*> LastValueMap;
typedef DenseMap<const Value*, Value*> ValueMapTy;
ValueMapTy LastValueMap;
std::vector<PHINode*> OrigPHINode;
for (BasicBlock::iterator I = Header->begin(); isa<PHINode>(I); ++I) {
PHINode *PN = cast<PHINode>(I);
@ -231,7 +232,7 @@ bool LoopUnroll::runOnLoop(Loop *L, LPPassManager &LPM) {
for (std::vector<BasicBlock*>::iterator BB = LoopBlocks.begin(),
E = LoopBlocks.end(); BB != E; ++BB) {
DenseMap<const Value*, Value*> ValueMap;
ValueMapTy ValueMap;
BasicBlock *New = CloneBasicBlock(*BB, ValueMap, SuffixBuffer);
Header->getParent()->getBasicBlockList().push_back(New);
@ -250,8 +251,8 @@ bool LoopUnroll::runOnLoop(Loop *L, LPPassManager &LPM) {
// Update our running map of newest clones
LastValueMap[*BB] = New;
for (DenseMap<const Value*, Value*>::iterator VI = ValueMap.begin(),
VE = ValueMap.end(); VI != VE; ++VI)
for (ValueMapTy::iterator VI = ValueMap.begin(), VE = ValueMap.end();
VI != VE; ++VI)
LastValueMap[VI->first] = VI->second;
L->addBasicBlockToLoop(New, *LI);
@ -291,30 +292,28 @@ bool LoopUnroll::runOnLoop(Loop *L, LPPassManager &LPM) {
}
// Update PHI nodes that reference the final latch block
// The latch block exits the loop. If there are any PHI nodes in the
// successor blocks, update them to use the appropriate values computed as the
// last iteration of the loop.
if (TripCount > 1) {
SmallPtrSet<PHINode*, 8> Users;
for (Value::use_iterator UI = LatchBlock->use_begin(),
UE = LatchBlock->use_end(); UI != UE; ++UI)
if (PHINode* phi = dyn_cast<PHINode>(*UI))
Users.insert(phi);
BasicBlock *LastIterationBB = cast<BasicBlock>(LastValueMap[LatchBlock]);
for (SmallPtrSet<PHINode*,8>::iterator SI = Users.begin(), SE = Users.end();
SI != SE; ++SI) {
PHINode *PN = *SI;
Value* InVal = PN->getIncomingValueForBlock(LatchBlock);
if (isa<Instruction>(InVal))
InVal = LastValueMap[InVal];
PN->removeIncomingValue(LatchBlock, false);
if (InVal)
PN->addIncoming(InVal, cast<BasicBlock>(LastValueMap[LatchBlock]));
if (PN->getNumIncomingValues() == 0) {
// Remove this phi node.
// If anyone is using this PHI, make them use a dummy value instead...
PN->replaceAllUsesWith(UndefValue::get(PN->getType()));
PN->eraseFromParent();
Value *InVal = PN->removeIncomingValue(LatchBlock, false);
// If this value was defined in the loop, take the value defined by the
// last iteration of the loop.
if (Instruction *InValI = dyn_cast<Instruction>(InVal)) {
if (L->contains(InValI->getParent()))
InVal = LastValueMap[InVal];
}
PN->addIncoming(InVal, LastIterationBB);
}
}