[PATCH] D110867: X86InstrInfo: Support immediates that are +1/-1 different in optimizeCompareInstr

[Craig Topper via Phabricator via llvm-commits]

craig.topper added a comment.

In D110867#3185871 <https://reviews.llvm.org/D110867#3185871>, @RKSimon wrote:

> In D110867#3185369 <https://reviews.llvm.org/D110867#3185369>, @MatzeB wrote:
>
>> Thanks for investigating and root-causing! I’m currently on vacation, please revert in the meantime.
>
> There appears to be one change:
> https://gcc.godbolt.org/z/TfKrs8M18
>
> llvm13:
>
>   shlq $32, %rax
>   testq %rax, %rax
>   je .LBB5_11
>   jle .LBB5_11
>
> (current) trunk:
>
>   shlq $32, %rax
>   je .LBB5_11
>   jle .LBB5_11

The jle would use the OF flag which isn't defined for shifts of more than 1. And even then doesn't have the same meaning.


Repository:
  rG LLVM Github Monorepo

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  https://reviews.llvm.org/D110867/new/

https://reviews.llvm.org/D110867