* [PATCH] i386: Use no-mmx,no-sse for LIBGCC2_UNWIND_ATTRIBUTE [PR104890]
@ 2022-03-15 9:18 Jakub Jelinek
2022-03-15 9:22 ` Richard Biener
0 siblings, 1 reply; 2+ messages in thread
From: Jakub Jelinek @ 2022-03-15 9:18 UTC (permalink / raw)
To: Richard Biener, Uros Bizjak; +Cc: gcc-patches
Hi!
Regardless of the outcome of the general-regs-only stuff in x86gprintrin.h,
apparently general-regs-only is much bigger hammer than no-sse, and e.g.
using 387 instructions in the unwinder isn't a big deal, it never needs
to realign the stack because of it.
So, the following patch uses no-sse (and adds no-mmx to it, even when not
strictly needed).
Bootstrapped/regtested on x86_64-linux and i686-linux, on the latter
both normally and with -msse2 -mfpmath=sse -mstackrealign in the options and
--enable-cet, ok for trunk?
2022-03-15 Jakub Jelinek <jakub@redhat.com>
PR target/104890
* config/i386/i386.h (LIBGCC2_UNWIND_ATTRIBUTE): Use no-mmx,no-sse
instead of general-regs-only.
--- gcc/config/i386/i386.h.jj 2022-03-09 15:25:28.355498493 +0100
+++ gcc/config/i386/i386.h 2022-03-14 15:27:33.831976579 +0100
@@ -2848,10 +2848,10 @@ extern enum attr_cpu ix86_schedule;
#define NUM_X86_64_MS_CLOBBERED_REGS 12
#endif
-/* __builtin_eh_return can't handle stack realignment, so restrict to
- general regs in 32-bit libgcc functions that call it. */
+/* __builtin_eh_return can't handle stack realignment, so disable MMX/SSE
+ in 32-bit libgcc functions that call it. */
#ifndef __x86_64__
-#define LIBGCC2_UNWIND_ATTRIBUTE __attribute__((target ("general-regs-only")))
+#define LIBGCC2_UNWIND_ATTRIBUTE __attribute__((target ("no-mmx,no-sse")))
#endif
/*
Jakub
^ permalink raw reply [flat|nested] 2+ messages in thread
* Re: [PATCH] i386: Use no-mmx,no-sse for LIBGCC2_UNWIND_ATTRIBUTE [PR104890]
2022-03-15 9:18 [PATCH] i386: Use no-mmx,no-sse for LIBGCC2_UNWIND_ATTRIBUTE [PR104890] Jakub Jelinek
@ 2022-03-15 9:22 ` Richard Biener
0 siblings, 0 replies; 2+ messages in thread
From: Richard Biener @ 2022-03-15 9:22 UTC (permalink / raw)
To: Jakub Jelinek; +Cc: Uros Bizjak, gcc-patches
On Tue, 15 Mar 2022, Jakub Jelinek wrote:
> Hi!
>
> Regardless of the outcome of the general-regs-only stuff in x86gprintrin.h,
> apparently general-regs-only is much bigger hammer than no-sse, and e.g.
> using 387 instructions in the unwinder isn't a big deal, it never needs
> to realign the stack because of it.
>
> So, the following patch uses no-sse (and adds no-mmx to it, even when not
> strictly needed).
>
> Bootstrapped/regtested on x86_64-linux and i686-linux, on the latter
> both normally and with -msse2 -mfpmath=sse -mstackrealign in the options and
> --enable-cet, ok for trunk?
OK.
> 2022-03-15 Jakub Jelinek <jakub@redhat.com>
>
> PR target/104890
> * config/i386/i386.h (LIBGCC2_UNWIND_ATTRIBUTE): Use no-mmx,no-sse
> instead of general-regs-only.
>
> --- gcc/config/i386/i386.h.jj 2022-03-09 15:25:28.355498493 +0100
> +++ gcc/config/i386/i386.h 2022-03-14 15:27:33.831976579 +0100
> @@ -2848,10 +2848,10 @@ extern enum attr_cpu ix86_schedule;
> #define NUM_X86_64_MS_CLOBBERED_REGS 12
> #endif
>
> -/* __builtin_eh_return can't handle stack realignment, so restrict to
> - general regs in 32-bit libgcc functions that call it. */
> +/* __builtin_eh_return can't handle stack realignment, so disable MMX/SSE
> + in 32-bit libgcc functions that call it. */
> #ifndef __x86_64__
> -#define LIBGCC2_UNWIND_ATTRIBUTE __attribute__((target ("general-regs-only")))
> +#define LIBGCC2_UNWIND_ATTRIBUTE __attribute__((target ("no-mmx,no-sse")))
> #endif
>
> /*
>
> Jakub
>
>
--
Richard Biener <rguenther@suse.de>
SUSE Software Solutions Germany GmbH, Maxfeldstrasse 5, 90409 Nuernberg,
Germany; GF: Ivo Totev; HRB 36809 (AG Nuernberg)
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