[Bug target/53759] gcc -mavx emits vshufps for__builtin_ia32_loadlps

[dag at nimrod dot no]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=53759

--- Comment #1 from Dag Lem <dag at nimrod dot no> 2012-06-24 12:45:55 UTC ---
Test code as follows:
------------------------
typedef float v4sf __attribute__ ((vector_size (4*4)));
typedef float v2sf __attribute__ ((vector_size (4*2)));

v2sf mem[1];

int main()
{
  v4sf reg = (v4sf){0,0,0,0};
  reg = __builtin_ia32_loadlps(reg, mem);
  return reg[0];
}
------------------------

With -msse, gcc emits the following code:

    xorps    %xmm0, %xmm0
    movlps    mem, %xmm0

However with -mavx, gcc emits:

    vxorps    %xmm0, %xmm0, %xmm0
    vmovlps    mem, %xmm1, %xmm1
    vshufps    $0xe4, %xmm0, %xmm1, %xmm0

Shouldn't this rather have been something like

    vxorps    %xmm0, %xmm0, %xmm0
    vmovlps    mem, %xmm0, %xmm0

???