[llvm] 3794cc0 - [InstCombine] invert canonicalization for cast of signbit test

[Florian Hahn via llvm-commits]

> On May 16, 2022, at 22:54, Sanjay Patel via llvm-commits <llvm-commits at lists.llvm.org> wrote:
> 
> Thanks for letting me know. Reverted:
> https://reviews.llvm.org/rG07d549bce94f <https://reviews.llvm.org/rG07d549bce94f>
> 
> If you can get the IR for that file, that would be great. Otherwise, I'll try to set up a system to extract that.


Sure, the IR below should hang with this patch and `opt -passes=instcombine`

define i8 @widget(i64 %arg) {
bb:
  %tmp = lshr i64 %arg, 7
  %tmp1 = and i64 %tmp, 1
  %tmp2 = trunc i64 %tmp1 to i32
  %tmp3 = icmp ne i32 %tmp2, 0
  %tmp4 = xor i1 %tmp3, true
  %tmp5 = zext i1 %tmp4 to i8
  ret i8 %tmp5
}


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