[Bug target/28366] New: Divide with vectors cause extra stores (and more stack space) (with VMX)

[pinskia at gcc dot gnu dot org]

Compile the following code with -maltivec -O2 -mabi=altivec -m64:
#define vector __attribute__((vector_size(16)))
vector float f(vector float t, vector float t1)
{
  return t / t1;
}
We currently get:
        addi 9,1,-36
        stvewx 2,0,9
        addi 9,1,-20
        stvewx 3,0,9
        addi 9,1,-144
        stvewx 2,0,9
        addi 9,1,-128
        stvewx 3,0,9
        addi 9,1,-108
        stvewx 2,0,9
        addi 9,1,-92
        stvewx 3,0,9
        addi 9,1,-72
        stvewx 2,0,9
        addi 9,1,-56
        stvewx 3,0,9
        addi 9,1,-16
....

Which is storing out each element of the vector one by one, instead of just
storing the whole vector out:
stvx 2, ...
stvx 3, ...


-- 
           Summary: Divide with vectors cause extra stores (and more stack
                    space) (with VMX)
           Product: gcc
           Version: 4.2.0
            Status: UNCONFIRMED
          Keywords: missed-optimization
          Severity: enhancement
          Priority: P3
         Component: target
        AssignedTo: unassigned at gcc dot gnu dot org
        ReportedBy: pinskia at gcc dot gnu dot org
GCC target triplet: powerpc-linux-gnu


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=28366