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Guard against huge loop trip counts in an APInt safe way.

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git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@34858 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Reid Spencer 2007-03-02 23:31:34 +00:00
parent ae6421935b
commit 4e69f48a0a
1 changed files with 7 additions and 2 deletions
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9
lib/Transforms/Scalar/LoopUnroll.cpp
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@ -190,10 +190,15 @@ bool LoopUnroll::visitLoop(Loop *L) {
ConstantInt *TripCountC = dyn_cast_or_null<ConstantInt>(L->getTripCount());
if (!TripCountC) return Changed; // Must have constant trip count!
uint64_t TripCountFull = TripCountC->getZExtValue();
if (TripCountFull != TripCountC->getZExtValue() || TripCountFull == 0)
// Guard against huge trip counts. This also guards against assertions in
// APInt from the use of getZExtValue, below.
if (TripCountC->getValue().getActiveBits() > 32)
return Changed; // More than 2^32 iterations???
uint64_t TripCountFull = TripCountC->getZExtValue();
if (TripCountFull == 0)
return Changed; // Zero iteraitons?
unsigned LoopSize = ApproximateLoopSize(L);
DOUT << "Loop Unroll: F[" << Header->getParent()->getName()
<< "] Loop %" << Header->getName() << " Loop Size = "