diff options
Diffstat (limited to 'test/Transforms/InstSimplify')
| -rw-r--r-- | test/Transforms/InstSimplify/2011-11-23-MaskedBitsCrash.ll | 17 |
1 files changed, 17 insertions, 0 deletions
diff --git a/test/Transforms/InstSimplify/2011-11-23-MaskedBitsCrash.ll b/test/Transforms/InstSimplify/2011-11-23-MaskedBitsCrash.ll new file mode 100644 index 0000000000..6166536726 --- /dev/null +++ b/test/Transforms/InstSimplify/2011-11-23-MaskedBitsCrash.ll @@ -0,0 +1,17 @@ +; RUN: opt < %s -instsimplify + +; The mul can be proved to always overflow (turning a negative value +; into a positive one) and thus results in undefined behaviour. At +; the same time we were deducing from the nsw flag that that mul could +; be assumed to have a negative value (since if not it has an undefined +; value, which can be taken to be negative). We were reporting the mul +; as being both positive and negative, firing an assertion! +define i1 @test1(i32 %a) { +entry: + %0 = or i32 %a, 1 + %1 = shl i32 %0, 31 + %2 = mul nsw i32 %1, 4 + %3 = and i32 %2, -4 + %4 = icmp ne i32 %3, 0 + ret i1 %4 +} |