[Bug c/50353] New: vec_set not used for vector indexing

[amylaar at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=50353

             Bug #: 50353
           Summary: vec_set not used for vector indexing
    Classification: Unclassified
           Product: gcc
           Version: 4.7.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: c
        AssignedTo: unassigned@gcc.gnu.org
        ReportedBy: amylaar@gcc.gnu.org


The code in c-typeck.c:build_array_ref that handles indexing of vector types
unconditionally calls c_common_mark_addressable_vec, thus disabling the use
of target-supplied vec_set patterns.

E.g.:

typedef float f2 __attribute__((vector_size(8)));

f2 f (f2 in)
{
  f2 tmp;

  tmp[0] = 3;
  tmp[1] = 5;

  return in * tmp;
}


tmp gets placed in memory before any optimizers can even run.