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From: "vincenzo.innocente at cern dot ch" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Subject: [Bug c++/61292] auto keyword to vector reference generates wrong alignment move (causing runtime segfault)
Date: Sun, 25 May 2014 12:19:00 -0000
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https://gcc.gnu.org/bugzilla/show_bug.cgi?id=61292

vincenzo Innocente <vincenzo.innocente at cern dot ch> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
            Summary|auto keyword to vector      |auto keyword to vector
                   |reference generates wrong   |reference generates wrong
                   |alignment move              |alignment move (causing
                   |                            |runtime segfault)

--- Comment #1 from vincenzo Innocente <vincenzo.innocente at cern dot ch> ---
interesting enough
void add14(float * x, float y, float32x4_t v) {
   decltype(auto) k1 = *(float32x4a4_t*)(x);
   decltype(auto) k2 = *(float32x4a4_t*)(x);
   k1 +=v;
   k2 += k1+v;
}

generates
__Z5add14PffU8__vectorf:
LFB5:
    vaddps    (%rdi), %xmm1, %xmm0
    vaddps    %xmm0, %xmm0, %xmm0
    vaddps    %xmm1, %xmm0, %xmm1
    vmovups    %xmm1, (%rdi)
    ret

so c++11 auto is loosing the alignment...
is this "standard" or bug?