For Windows x86-32 targets, the Microsoft ABI only guarantees that the stack is aligned to 4-byte boundaries. GCC knows about the default alignment of the stack. However, before this commit, it did not realign the stack unless SSE was also enabled.
When a stricter (larger) alignment is requested, it's always necessary to realign the stack, as what Solaris does. Reference: https://gcc.gnu.org/bugzilla/show_bug.cgi?id=111107#c14 Signed-off-by: LIU Hao <lh_mo...@126.com> gcc/ChangeLog: PR target/111107 * config/i386/cygming.h (STACK_REALIGN_DEFAULT): Copy from sol2.h. --- gcc/config/i386/cygming.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/gcc/config/i386/cygming.h b/gcc/config/i386/cygming.h index 3ddcbecb22fd..d587d25a58a8 100644 --- a/gcc/config/i386/cygming.h +++ b/gcc/config/i386/cygming.h @@ -36,7 +36,7 @@ along with GCC; see the file COPYING3. If not see /* 32-bit Windows aligns the stack on a 4-byte boundary but SSE instructions may require 16-byte alignment. */ #undef STACK_REALIGN_DEFAULT -#define STACK_REALIGN_DEFAULT TARGET_SSE +#define STACK_REALIGN_DEFAULT (TARGET_64BIT ? 0 : 1) /* Support hooks for SEH. */ #undef TARGET_ASM_UNWIND_EMIT -- 2.49.0
From d043b30147e00231a99012d631bfc6291340b283 Mon Sep 17 00:00:00 2001 From: LIU Hao <lh_mo...@126.com> Date: Sun, 27 Apr 2025 18:18:34 +0800 Subject: [PATCH] gcc: For Windows x86-32, always attempt to realign stack regardless of SSE For Windows x86-32 targets, the Microsoft ABI only guarantees that the stack is aligned to 4-byte boundaries. GCC knows about the default alignment of the stack. However, before this commit, it did not realign the stack unless SSE was also enabled. When a stricter (larger) alignment is requested, it's always necessary to realign the stack, as what Solaris does. Reference: https://gcc.gnu.org/bugzilla/show_bug.cgi?id=111107#c14 Signed-off-by: LIU Hao <lh_mo...@126.com> gcc/ChangeLog: PR target/111107 * config/i386/cygming.h (STACK_REALIGN_DEFAULT): Copy from sol2.h. --- gcc/config/i386/cygming.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/gcc/config/i386/cygming.h b/gcc/config/i386/cygming.h index 3ddcbecb22fd..d587d25a58a8 100644 --- a/gcc/config/i386/cygming.h +++ b/gcc/config/i386/cygming.h @@ -36,7 +36,7 @@ along with GCC; see the file COPYING3. If not see /* 32-bit Windows aligns the stack on a 4-byte boundary but SSE instructions may require 16-byte alignment. */ #undef STACK_REALIGN_DEFAULT -#define STACK_REALIGN_DEFAULT TARGET_SSE +#define STACK_REALIGN_DEFAULT (TARGET_64BIT ? 0 : 1) /* Support hooks for SEH. */ #undef TARGET_ASM_UNWIND_EMIT -- 2.49.0
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