| ; 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 |
| } |