mirror of
https://github.com/RPCS3/llvm-mirror.git
synced 2024-11-23 19:23:23 +01:00
18 lines
605 B
LLVM
18 lines
605 B
LLVM
|
; 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
|
||
|
|
}
|