[PATCH] D34897: Change default for -print-whole-regmask to false

Matthias Braun via Phabricator via llvm-commits llvm-commits at lists.llvm.org
Fri Jun 30 12:09:23 PDT 2017


MatzeB added a comment.

In https://reviews.llvm.org/D34897#797097, @arsenm wrote:

> In https://reviews.llvm.org/D34897#797095, @MatzeB wrote:
>
> > Some thoughts:
> >
> > - Is this motivated by AMDGPU having a huge number of registers in the mask?
>
>
> Yes. It more than fills my fullscreen terminal window on any call. It wouldn't be so bad if it printed just regunits, but this also prints all of the register tuple combinations as well.




- Unfortunately regmasks cannot be expressed in regunits today. The canonical example is `xmm0` and `ymm0` on X86 occuying the exact same register units (because the extra bits of ymm0 cannot be addressed/named independently) but they are still separate registers having different clobbering behavior in some calling conventions.


https://reviews.llvm.org/D34897





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