http://gcc.gnu.org/bugzilla/show_bug.cgi?id=59041
Bug ID: 59041
Summary: [4.8/4.9 Regression] Unnecessary vzeroupper generated
Product: gcc
Version: 4.9.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: target
Assignee: unassigned at gcc dot gnu.org
Reporter: hjl.tools at gmail dot com
CC: ubizjak at gmail dot com
[hjl@gnu-6 gcc]$ cat /tmp/j.cc
#include <setjmp.h>
extern jmp_buf buf;
struct xxx
{
int foo ();
int i;
};
static void __attribute__((noinline))
bar (jmp_buf buf)
{
__builtin_longjmp (buf, 1);
}
int
xxx::foo ()
{
int j = i + 1;
if (!__builtin_setjmp (buf))
{
j += 1;
bar (buf);
}
return j + i;
}
[hjl@gnu-6 gcc]$ ./xgcc -B./ -S -O2 -mavx /tmp/j.cc
[hjl@gnu-6 gcc]$ cat j.s
.file "j.cc"
.section .text.unlikely,"ax",@progbits
.type _ZL3barP13__jmp_buf_tag.constprop.0, @function
_ZL3barP13__jmp_buf_tag.constprop.0:
.LFB2:
.cfi_startproc
pushq %rbp
.cfi_def_cfa_offset 16
.cfi_offset 6, -16
movq buf+8(%rip), %rax
movq %rsp, %rbp
.cfi_def_cfa_register 6
movq buf(%rip), %rbp
movq buf+16(%rip), %rsp
jmp *%rax
.cfi_endproc
.LFE2:
.size _ZL3barP13__jmp_buf_tag.constprop.0,
.-_ZL3barP13__jmp_buf_tag.constprop.0
.text
.align 2
.p2align 4,,15
.globl _ZN3xxx3fooEv
.type _ZN3xxx3fooEv, @function
_ZN3xxx3fooEv:
.LFB1:
.cfi_startproc
pushq %r15
.cfi_def_cfa_offset 16
.cfi_offset 15, -16
pushq %r14
.cfi_def_cfa_offset 24
.cfi_offset 14, -24
pushq %r13
.cfi_def_cfa_offset 32
.cfi_offset 13, -32
pushq %r12
.cfi_def_cfa_offset 40
.cfi_offset 12, -40
pushq %rbp
.cfi_def_cfa_offset 48
.cfi_offset 6, -48
pushq %rbx
.cfi_def_cfa_offset 56
.cfi_offset 3, -56
subq $16, %rsp
.cfi_def_cfa_offset 72
movl (%rdi), %eax
movq $.L4, buf+8(%rip)
leaq 16(%rsp), %rcx
movq %rdi, 8(%rsp)
movq %rsp, buf+16(%rip)
addl $2, %eax
movq %rcx, buf(%rip)
movl %eax, 4(%rsp)
call _ZL3barP13__jmp_buf_tag.constprop.0
.L7:
.p2align 4,,10
.p2align 3
.L4:
movq 8(%rsp), %rdx
movl 4(%rsp), %eax
addl (%rdx), %eax
vzeroupper <<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<< Unnecessary vzeroupper
addq $16, %rsp
.cfi_def_cfa_offset 56
popq %rbx
.cfi_def_cfa_offset 48
popq %rbp
.cfi_def_cfa_offset 40
popq %r12
.cfi_def_cfa_offset 32
popq %r13
.cfi_def_cfa_offset 24
popq %r14
.cfi_def_cfa_offset 16
popq %r15
.cfi_def_cfa_offset 8
ret
.cfi_endproc
.LFE1:
.size _ZN3xxx3fooEv, .-_ZN3xxx3fooEv
.ident "GCC: (GNU) 4.9.0 20131106 (experimental)"
.section .note.GNU-stack,"",@progbits
[hjl@gnu-6 gcc]$
