[gcc r12-7565] x86: Define LIBGCC2_UNWIND_ATTRIBUTE on ia32 [PR104781]

[gcc r12-7565] x86: Define LIBGCC2_UNWIND_ATTRIBUTE on ia32 [PR104781]

[Jakub Jelinek]

https://gcc.gnu.org/g:caa6c33c5d5223c50657b08e73177e8d54ceee51

commit r12-7565-gcaa6c33c5d5223c50657b08e73177e8d54ceee51
Author: Jakub Jelinek <jakub@redhat.com>
Date:   Wed Mar 9 15:25:30 2022 +0100

    x86: Define LIBGCC2_UNWIND_ATTRIBUTE on ia32 [PR104781]
    
    On Mon, Mar 07, 2022 at 07:06:28AM -0800, H.J. Lu wrote:
    > Since eh_return doesn't work with stack realignment, disable SSE on
    > unwind-c.c and unwind-dw2.c to avoid stack realignment with the 4-byte
    > incoming stack to avoid SSE usage which is caused by
    
    The following change does that using LIBGCC2_UNWIND_ATTRIBUTE macro instead,
    for ia32 only by forcing -mgeneral-regs-only on routines that call
    __builtin_eh_return in libgcc.
    
    2022-03-09  Jakub Jelinek  <jakub@redhat.com>
    
            PR target/104781
            * config/i386/i386.h (LIBGCC2_UNWIND_ATTRIBUTE): Define for ia32.

Diff:
---
 gcc/config/i386/i386.h | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/gcc/config/i386/i386.h b/gcc/config/i386/i386.h
index b37d4a9966a..0d28e57f8f2 100644
--- a/gcc/config/i386/i386.h
+++ b/gcc/config/i386/i386.h
@@ -2848,6 +2848,12 @@ 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.  */
+#ifndef __x86_64__
+#define LIBGCC2_UNWIND_ATTRIBUTE __attribute__((target ("general-regs-only")))
+#endif
+
 /*
 Local variables:
 version-control: t