When checking for signed multiplication overflow, watch out for INT_MIN and -1.
This fixes PR9845.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@131919 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Transforms/Scalar/LoopStrengthReduce.cpp b/lib/Transforms/Scalar/LoopStrengthReduce.cpp
index 204ce36..73ebd61 100644
--- a/lib/Transforms/Scalar/LoopStrengthReduce.cpp
+++ b/lib/Transforms/Scalar/LoopStrengthReduce.cpp
@@ -2522,6 +2522,8 @@
// Check that multiplying with the unfolded offset doesn't overflow.
if (F.UnfoldedOffset != 0) {
+ if (F.UnfoldedOffset == INT64_MIN && Factor == -1)
+ continue;
F.UnfoldedOffset = (uint64_t)F.UnfoldedOffset * Factor;
if (F.UnfoldedOffset / Factor != Base.UnfoldedOffset)
continue;