[Bug target/24073] New: (vector float){a, b, 0, 0} code gen is not good

["pinskia at gcc dot gnu dot org" <gcc-bugzilla@gcc.gnu.org>]

Take the following example:
#define vector __attribute__((vector_size(16)))

float a; float b;
vector float f(void) { return (vector float){ a, b, 0.0, 0.0}; }
---
Currently we get:
        subl    $12, %esp
        movss   _b, %xmm0
        movss   _a, %xmm1
        unpcklps        %xmm0, %xmm1
        movaps  %xmm1, %xmm0
        xorl    %eax, %eax
        xorl    %edx, %edx
        movl    %eax, (%esp)
        movl    %edx, 4(%esp)
        xorps   %xmm1, %xmm1
        movlhps %xmm1, %xmm0
        addl    $12, %esp

------
We should be able to produce:
movss _b, %xmm0
movss _a, %xmm1
shufps 60, /*[0, 3, 3, 0]*/, %xmm1, %xmm0 // _a, 0, 0, _b
shufps 201, /*[3, 0, 2, 1]*/, %xmm0, %xmm0 // _a, _b, 0, 0

This is from Nathan Begeman.

-- 
           Summary: (vector float){a, b, 0, 0} code gen is not good
           Product: gcc
           Version: 4.1.0
            Status: UNCONFIRMED
          Keywords: missed-optimization
          Severity: minor
          Priority: P2
         Component: target
        AssignedTo: unassigned at gcc dot gnu dot org
        ReportedBy: pinskia at gcc dot gnu dot org
                CC: gcc-bugs at gcc dot gnu dot org


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=24073