[Bug middle-end/49168] New: [4.7 Regression] Aligned store used with unaligned address

[hjl.tools at gmail dot com]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=49168

           Summary: [4.7 Regression] Aligned store used with unaligned
                    address
           Product: gcc
           Version: 4.7.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: middle-end
        AssignedTo: unassig...@gcc.gnu.org
        ReportedBy: hjl.to...@gmail.com
                CC: rgue...@gcc.gnu.org


On Linux/x86-64, revision 174223 gave

[hjl@gnu-6 gcc]$ cat /tmp/x.c
#include <stdarg.h>

void
flt128_va (void *mem, va_list *ap)
{ 
  __float128 d = va_arg (*ap, __float128);
  __builtin_memcpy (mem, &d, sizeof (d));
}
[hjl@gnu-6 gcc]$ ./xgcc -B./ -O2 -S /tmp/x.c 
[hjl@gnu-6 gcc]$ cat x.s
    .file    "x.c"
    .text
    .p2align 4,,15
    .globl    flt128_va
    .type    flt128_va, @function
flt128_va:
.LFB0:
    .cfi_startproc
    movl    4(%rsi), %edx
    cmpl    $176, %edx
    jb    .L5
    movq    8(%rsi), %rax
    addq    $15, %rax
    andq    $-16, %rax
    leaq    16(%rax), %rdx
    movq    %rdx, 8(%rsi)
    movdqa    (%rax), %xmm0
    movdqa    %xmm0, (%rdi)
    ret
    .p2align 4,,10
    .p2align 3
.L5:
    mov    %edx, %eax
    addq    16(%rsi), %rax
    addl    $16, %edx
    movl    %edx, 4(%rsi)
    movdqa    (%rax), %xmm0
    movdqa    %xmm0, (%rdi)
    ret
    .cfi_endproc
.LFE0:
    .size    flt128_va, .-flt128_va

It may be caused by revision 174206:

http://gcc.gnu.org/ml/gcc-cvs/2011-05/msg00987.html