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Re: [PATCH 2/4] prologue and epilogue tidy and -mno-vrsave bug fix


On Sun, May 17, 2015 at 10:54 PM, Alan Modra <amodra@gmail.com> wrote:
> This patch tidies the prologue and epilogue altivec code a little.
> A number of places using info->altivec_size unnecessarily also test
> TARGET_ALTIVEC_ABI, when rs6000_stack_info() guarantees that
> info->altivec_size is zero if !TARGET_ALTIVEC_ABI.
>
> Similarly by inspection of rs6000_stack_info() code,
> TARGET_ALTIVEC_VRSAVE && info->vrsave_mask != 0, used when deciding to
> save or restore vrsave, can be replaced with info->vrsave_size.  I
> also removed the TARGET_ALTIVEC test used with save/restore of vrsave.
> I believe it is redundant because compute_vrsave_mask() will return 0
> when no altivec registers are used (and of course you can't use then
> without TARGET_ALTIVEC), except for Darwin where TARGET_ALTIVEC is
> forced.  The vrsave changes make the code actually doing the save or
> restore visually consistent with code that sets up a frame register
> for vrsave.
>
> Finally, I've changed two places that use info->vrsave_mask to test
> whether vrsave is saved or restored, to use info->vrsave_size.  This
> is a bug fix for -mno-vrsave.
>
>         * config/rs6000/rs6000.c (struct rs6000_stack): Correct comments.
>         (rs6000_stack_info): Don't zero offsets when not saving registers.
>         (debug_stack_info): Adjust to omit printing unused offsets,
>         as before.
>         (direct_return): Test vrsave_size rather than vrsave_mask.
>         (rs6000_emit_prologue): Likewise.  Remove redundant altivec tests.
>         (rs6000_emit_epilogue): Likewise.

This patch is okay.

My only concern is Patch 1 causing a regression for the PR that I mentioned.

Thanks, David


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