[PATCH] D25485: [x86] use 'neg' for negation of bool

[Daniel Sanders via llvm-commits]

dsanders added a comment.

In https://reviews.llvm.org/D25485#569279, @sdardis wrote:

> We don't have a negate instruction, we use "nor $dst, $src, $zero"  instead. "nor" present in all our ISAs except mips16 which has an actual negate instruction.
>
> Did that regression hit general MIPS code or just microMIPS? It's possible that we have a missing pattern for microMIPS in that case. I'll give this patch a whirl.


Arithmetic and bitwise negation are equivalent in this case but just to mention it. The arithmetic negation is 'sub $dst, $zero, $src'. IIRC, GAS has a 'neg' alias for this but I don't think it's implemented in LLVM yet.


https://reviews.llvm.org/D25485