[Bug rtl-optimization/60819] New: dse1 removing not-dead insn (aliasing issue?)

[glisse at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=60819

            Bug ID: 60819
           Summary: dse1 removing not-dead insn (aliasing issue?)
           Product: gcc
           Version: 4.9.0
            Status: UNCONFIRMED
          Keywords: wrong-code
          Severity: normal
          Priority: P3
         Component: rtl-optimization
          Assignee: unassigned at gcc dot gnu.org
          Reporter: glisse at gcc dot gnu.org
            Target: x86_64-linux-gnu

#include <mmintrin.h>

int f (__m64 const __A, int const __N)
{ return ((__v4hi)__A)[__N]; }


compiler with -O2, produces:

    movslq    %edi, %rdi
    movswl    -8(%rsp,%rdi,2), %eax
    ret

dse1 removed the instruction that copies xmm0 to the stack!

Could be related to PR 56965, I didn't try the patch in that PR.
Already broken in gcc-4.6, not a (recent) regression.