[Bug target/52419] Wrong expansion of misaligned vector store

[rguenth at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=52419

Richard Guenther <rguenth at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|REOPENED                    |NEW

--- Comment #3 from Richard Guenther <rguenth at gcc dot gnu.org> 2012-02-29 13:28:00 UTC ---
Confirmed.

foo:
.LFB0:
        .cfi_startproc
        pxor    %xmm1, %xmm1
        movhps  .LC0(%rip), %xmm1
        movdqu  %xmm1, (%rdi)
        ret

it looks like 

(insn 6 5 7 (set (reg:DI 61)
        (const_int 5 [0x5])) t.c:23 -1
     (nil))

(insn 7 6 8 (set (reg:DI 62)
        (vec_select:DI (reg:V2DI 60)
            (parallel [
                    (const_int 0 [0])
                ]))) t.c:23 -1
     (nil))

(insn 8 7 9 (set (reg:V2DI 60)
        (vec_concat:V2DI (reg:DI 62)
            (reg:DI 61))) t.c:23 -1
     (nil))

(insn 9 8 0 (set (mem:V16QI (reg/v/f:DI 59 [ p ]) [0 *p_1(D)+0 S16 A8])
        (unspec:V16QI [
                (subreg:V16QI (reg:V2DI 60) 0)
            ] UNSPEC_MOVU)) t.c:23 -1
     (nil))

which of course does not work as ref:V2DI 60 is unsed uninitialized in insn 7.