[Bug c/14321] New: gcc emitting "movaps" to unaligned memory

["M dot Drochner at fz-juelich dot de" <gcc-bugzilla at gcc dot gnu dot org>]

In conjunction with "va_start" usage the following code is emitted:

  37:   48 8d 0d 2f 00 00 00    lea    47(%rip),%rcx   # 6d <_snprintf+0x6d>
  3e:   48 29 c1                sub    %rax,%rcx
  41:   85 f6                   test   %esi,%esi
  43:   48 8d 84 24 1f 03 00    lea    0x31f(%rsp,1),%rax
  4a:   00
  4b:   ff e1                   jmpq   *%ecx
  4d:   0f 29 78 f1             movaps %xmm7,0xfffffffffffffff1(%rax)
  51:   0f 29 70 e1             movaps %xmm6,0xffffffffffffffe1(%rax)
  55:   0f 29 68 d1             movaps %xmm5,0xffffffffffffffd1(%rax)
  59:   0f 29 60 c1             movaps %xmm4,0xffffffffffffffc1(%rax)
  5d:   0f 29 58 b1             movaps %xmm3,0xffffffffffffffb1(%rax)
  61:   0f 29 50 a1             movaps %xmm2,0xffffffffffffffa1(%rax)
  65:   0f 29 48 91             movaps %xmm1,0xffffffffffffff91(%rax)
  69:   0f 29 40 81             movaps %xmm0,0xffffffffffffff81(%rax)
  6d:   0f 88 24 01 00 00       js     197 <_snprintf+0x197>

The "movaps" needs 16-byte aligned memory locations, which is not
ensured (only 8-byte, appearently). This leads to occasional GPFs,
sepending on the initial stack pointer.

-- 
           Summary: gcc emitting "movaps" to unaligned memory
           Product: gcc
           Version: 3.3.3
            Status: UNCONFIRMED
          Severity: normal
          Priority: P2
         Component: c
        AssignedTo: unassigned at gcc dot gnu dot org
        ReportedBy: M dot Drochner at fz-juelich dot de
                CC: gcc-bugs at gcc dot gnu dot org
  GCC host triplet: x86_64--netbsd
GCC target triplet: x86_64--netbsd


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=14321