[Bug tree-optimization/104501] New: vector lowering for VEC_COND_EXPR does not consider smaller vectors

[rguenth at gcc dot gnu.org via Gcc-bugs]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=104501

            Bug ID: 104501
           Summary: vector lowering for VEC_COND_EXPR does not consider
                    smaller vectors
           Product: gcc
           Version: 12.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: tree-optimization
          Assignee: unassigned at gcc dot gnu.org
          Reporter: rguenth at gcc dot gnu.org
  Target Milestone: ---

The following C++ testcase is decomposed to scalar operations by vector
lowering when compiling with just SSE2 support.  But when using a vector size
of 16 we
can produce optimized code.

typedef int vsi __attribute__((vector_size(32)));

vsi res, v1, v2, v3, v4;

void foo ()
{
  res = v1 == v2 ? v3 : v4;
}