https://gcc.gnu.org/bugzilla/show_bug.cgi?id=126165
Bug ID: 126165
Summary: INSN_SCHEDULING should generate reg->reg move instead
of load
Product: gcc
Version: 17.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: rtl-optimization
Assignee: unassigned at gcc dot gnu.org
Reporter: hjl.tools at gmail dot com
Target Milestone: ---
[hjl@gnu-tgl-3 pr125297]$ cat x.c
#include <stdarg.h>
extern void continuation (int, ...);
void
entry (int i, ...)
{
va_list argp;
va_start (argp, i);
int arg1 = va_arg (argp, int);
int arg2 = va_arg (argp, int);
int arg3 = va_arg (argp, int);
int arg4 = va_arg (argp, int);
int arg5 = va_arg (argp, int);
continuation (i, arg1, arg2, arg3, arg4, arg5);
}
[hjl@gnu-tgl-3 pr125297]$ /usr/gcc-16.1.1-x32/bin/gcc -S -O2 x.c
[hjl@gnu-tgl-3 pr125297]$ cat x.s
.file "x.c"
.text
.p2align 4
.globl entry
.type entry, @function
entry:
.LFB0:
.cfi_startproc
subq $88, %rsp
.cfi_def_cfa_offset 96
leaq 96(%rsp), %rax
movq %rsi, 40(%rsp)
movl 40(%rsp), %esi
movq %rdx, 48(%rsp)
movl 48(%rsp), %edx
movq %rcx, 56(%rsp)
movl 56(%rsp), %ecx
movq %r8, 64(%rsp)
movl 64(%rsp), %r8d
movq %r9, 72(%rsp)
movl 72(%rsp), %r9d
movq %rax, 16(%rsp)
leaq 32(%rsp), %rax
movq %rax, 24(%rsp)
xorl %eax, %eax
movl $8, 8(%rsp)
call continuation
addq $88, %rsp
.cfi_def_cfa_offset 8
ret
.cfi_endproc
.LFE0:
.size entry, .-entry
.ident "GCC: (GNU) 16.1.1 20260516"
.section .note.GNU-stack,"",@progbits
[hjl@gnu-tgl-3 pr125297]$
INSN_SCHEDULING should generate
movq %rsi, 40(%rsp)
movl %esi, %esi
instead of
movq %rsi, 40(%rsp)
movl 40(%rsp), %esi
