[llvm-commits] CVS: llvm/lib/Transforms/Scalar/LoopUnroll.cpp

[Reid Spencer]

Changes in directory llvm/lib/Transforms/Scalar:

LoopUnroll.cpp updated: 1.36 -> 1.37
---
Log message:

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


---
Diffs of the changes:  (+7 -2)

 LoopUnroll.cpp |    9 +++++++--
 1 files changed, 7 insertions(+), 2 deletions(-)


Index: llvm/lib/Transforms/Scalar/LoopUnroll.cpp
diff -u llvm/lib/Transforms/Scalar/LoopUnroll.cpp:1.36 llvm/lib/Transforms/Scalar/LoopUnroll.cpp:1.37
--- llvm/lib/Transforms/Scalar/LoopUnroll.cpp:1.36	Mon Feb  5 17:32:05 2007
+++ llvm/lib/Transforms/Scalar/LoopUnroll.cpp	Fri Mar  2 17:31:34 2007
@@ -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 = "