[Bug tree-optimization/39331] New: OpenMP and return-slot-optimization generate invalid gimple

[rguenth at gcc dot gnu dot org]

from libgomp.c++/pr27337.C at -O3 we get in 042i.inline

  ret.12_15 = &x.8;
  .omp_data_o.11.ret ={v} ret.12_15;
  __builtin_GOMP_parallel_start (_Z3barv.omp_fn.0, &.omp_data_o.11, 4);
  _Z3barv.omp_fn.0 (&.omp_data_o.11);
  __builtin_GOMP_parallel_end ();
  ret.13_16 = .omp_data_o.11.ret;
  &x.8 = ret.13_16;

in main() from inlining foo() here:

<bb 8>:
  x.8 ={v} bar (); [return slot optimization]
  x ={v} x.8;

where bar () looks like

S bar() ()
{
  struct S & ret.5;
  struct .omp_data_s.10 .omp_data_o.11;
  struct S & ret.12;
  struct S & ret.13;

<bb 2>:
  ret.5_1 = <retval>;
  __comp_ctor  (ret.5_1);
  ret.12_2 = <retval>;
  .omp_data_o.11.ret ={v} ret.12_2;
  __builtin_GOMP_parallel_start (_Z3barv.omp_fn.0, &.omp_data_o.11, 4);
  _Z3barv.omp_fn.0 (&.omp_data_o.11);
  __builtin_GOMP_parallel_end ();
  ret.13_3 = .omp_data_o.11.ret;
  <retval> ={v} ret.13_3;
  return <retval>;

}

which is no longer in a form suitable for RSO.

The wrong-gimple is not catched by any verification at the moment (huh...)
but will ICE momentarily during PTA on the alias-improvements branch.

I didn't check if this is in any way a regression.


-- 
           Summary: OpenMP and return-slot-optimization generate invalid
                    gimple
           Product: gcc
           Version: 4.4.0
            Status: UNCONFIRMED
          Keywords: wrong-code
          Severity: normal
          Priority: P3
         Component: tree-optimization
        AssignedTo: unassigned at gcc dot gnu dot org
        ReportedBy: rguenth at gcc dot gnu dot org


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=39331