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restructure this a bit. Initialize the WeakVH with "I", the 

instruction *after* the store.  The store will always be deleted
if the transformation kicks in, so we'd do an N^2 scan of every
loop block.  Whoops.

llvm-svn: 122805
This commit is contained in:
Chris Lattner 2011-01-04 07:27:30 +00:00
parent e0cee6a8b0
commit a62b01dc37
1 changed files with 14 additions and 11 deletions
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25
llvm/lib/Transforms/Scalar/LoopIdiomRecognize.cpp
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@ -207,19 +207,22 @@ bool LoopIdiomRecognize::runOnLoopBlock(BasicBlock *BB, const SCEV *BECount,
bool MadeChange = false;
for (BasicBlock::iterator I = BB->begin(), E = BB->end(); I != E; ) {
// Look for store instructions, which may be memsets.
StoreInst *SI = dyn_cast<StoreInst>(I++);
if (SI == 0 || SI->isVolatile()) continue;
Instruction *Inst = I++;
// Look for store instructions, which may be optimized to memset/memcpy.
if (StoreInst *SI = dyn_cast<StoreInst>(Inst)) {
if (SI->isVolatile()) continue;
WeakVH InstPtr(SI);
if (!processLoopStore(SI, BECount)) continue;
WeakVH InstPtr(I);
if (!processLoopStore(SI, BECount)) continue;
MadeChange = true;
// If processing the store invalidated our iterator, start over from the
// head of the loop.
if (InstPtr == 0)
I = BB->begin();
continue;
}
MadeChange = true;
// If processing the store invalidated our iterator, start over from the
// head of the loop.
if (InstPtr == 0)
I = BB->begin();
}
return MadeChange;