[PATCH] i386: Make xmm16-xmm31 call used even in ms ABI

[Jakub Jelinek]

On Thu, Feb 06, 2020 at 01:00:36AM +0000, JonY wrote:
> On 2/4/20 11:42 AM, Jakub Jelinek wrote:
> > Hi!
> > 
> > On Tue, Feb 04, 2020 at 11:16:06AM +0100, Uros Bizjak wrote:
> >> I guess that Comment #9 patch form the PR should be trivially correct,
> >> but althouhg it looks obvious, I don't want to propose the patch since
> >> I have no means of testing it.
> > 
> > I don't have means of testing it either.
> > https://docs.microsoft.com/en-us/cpp/build/x64-calling-convention?view=vs-2019
> > is quite explicit that [xyz]mm16-31 are call clobbered and only xmm6-15 (low
> > 128-bits only) are call preserved.
> > 
> > Jonathan, could you please test this if it is sufficient to just change
> > CALL_USED_REGISTERS or if e.g. something in the pro/epilogue needs tweaking
> > too?  Thanks.
> 
> Is this patch testing still required? I just got back from traveling.

Yes, our reading of the MS ABI docs show that xmm16-31 are to be call used
(not preserved over calls), while in gcc they are currently handled as
preserved across the calls.

	Jakub