Guard against huge loop trip counts in an APInt safe way.
llvm-svn: 34858
diff --git a/llvm/lib/Transforms/Scalar/LoopUnroll.cpp b/llvm/lib/Transforms/Scalar/LoopUnroll.cpp
index d1770da..b0db806 100644
--- a/llvm/lib/Transforms/Scalar/LoopUnroll.cpp
+++ b/llvm/lib/Transforms/Scalar/LoopUnroll.cpp
@@ -190,10 +190,15 @@
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 = "