[PATCH] D77851: [X86][MC] Make -x86-pad-max-prefix-size compatible with --mc-relax-all

Fri Apr 17 02:40:36 PDT 2020

skan added a comment.

In D77851#1988272 <https://reviews.llvm.org/D77851#1988272>, @Razer6 wrote:

> In D77851#1988191 <https://reviews.llvm.org/D77851#1988191>, @MaskRay wrote:
>
> > > Which way do you think is better? Personally, I prefer the second one, since `getAssembler().getBackend().relaxInstruction(Relaxed, STI, Relaxed)` is called in a loop, the assumption that third argument of `relaxInstruction` is a fresh uninitialized `MCInst` is very strange.
> >
> > Special casing RISC-V looks good to me.
>
>
> A special case is probably also needed for the Hexagon and AMDGPU backend, which does similar stuff in their `relaxInstruction` implementation than the RISC-V backend.
>
> Is their any reason why `relaxInstruction` takes three argurments? Since `relaxed` is given in two arguments which are aliased to the same variable, I would drop the third argument and let  `relaxInstruction` to either modify the given instruction or assign it to a fresh one (RISC-V, Hexagon, AMDGPU case).

Droppng the third argument looks good to me.

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https://reviews.llvm.org/D77851