http://gcc.gnu.org/bugzilla/show_bug.cgi?id=56560
Bug #: 56560
Summary: [4.7 regression] vzeroupper clobbers argument with AVX
Classification: Unclassified
Product: gcc
Version: 4.7.3
Status: UNCONFIRMED
Keywords: wrong-code
Severity: normal
Priority: P3
Component: target
AssignedTo: [email protected]
ReportedBy: [email protected]
Target: x86_64-*-*
The vzeroupper optimization pass can go awry on the 4.7 branch and clobbers
arguments passed to functions:
eric@polaris:~> cat t.c
/* { dg-do compile } */
/* { dg-options "-O2 -mavx" } */
extern void abort (void);
typedef double vec_t __attribute__((vector_size(32)));
struct S { int i1; int i2; int i3; };
extern int bar (vec_t, int, int, int, int, int, struct S);
void foo (vec_t v, struct S s)
{
int i = bar (v, 1, 2, 3, 4, 5, s);
if (i == 0)
abort ();
}
/* { dg-final { scan-assembler-not "vzeroupper" } } */
eric@polaris:~> ~/install/gcc-4_7-branch/bin/gcc -S -O2 -mavx t.c
eric@polaris:~> cat t.s
.file "t.c"
.text
.p2align 4,,15
.globl foo
.type foo, @function
foo:
.LFB0:
.cfi_startproc
pushq %rbp
.cfi_def_cfa_offset 16
.cfi_offset 6, -16
movl $5, %r8d
movl $4, %ecx
movl $3, %edx
movq %rsp, %rbp
.cfi_def_cfa_register 6
andq $-32, %rsp
subq $64, %rsp
movq %rdi, (%rsp)
movl %esi, 8(%rsp)
movl $1, %edi
movl $2, %esi
vzeroupper
call bar
testl %eax, %eax
je .L5
leave
.cfi_remember_state
.cfi_def_cfa 7, 8
ret
.L5:
.cfi_restore_state
.p2align 4,,9
call abort
.cfi_endproc
