[Bug tree-optimization/66851] New: support double reduction in parloops

[Bug tree-optimization/66851] New: support double reduction in parloops

[vries at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=66851

            Bug ID: 66851
           Summary: support double reduction in parloops
           Product: gcc
           Version: unknown
            Status: UNCONFIRMED
          Severity: enhancement
          Priority: P3
         Component: tree-optimization
          Assignee: unassigned at gcc dot gnu.org
          Reporter: vries at gcc dot gnu.org
  Target Milestone: ---

outer-4.c contains an xfail:
...
/* { dg-do compile } */
/* { dg-options "-O2 -ftree-parallelize-loops=4 -fdump-tree-parloops-details
-fdump-tree-optimized" } */

void abort (void);

int g_sum=0;
int x[500][500];

__attribute__((noinline))
void parloop (int N)
{
  int i, j;
  int sum;

  /* Double reduction is currently not supported, outer loop is not
     parallelized.  Inner reduction is detected, inner loop is
     parallelized.  */
  sum = 0;
  for (i = 0; i < N; i++)
    for (j = 0; j < N; j++)
      sum += x[i][j];

  g_sum = sum;
}

int main(void)
{
  parloop(500);

  return 0;
}


/* { dg-final { scan-tree-dump-times "parallelizing outer loop" 1 "parloops" {
xfail *-*-* } } } */
/* { dg-final { scan-tree-dump-times "loopfn" 4 "optimized" } } */
...

[Bug tree-optimization/66851] support double reduction in parloops

[vries at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=66851

--- Comment #1 from vries at gcc dot gnu.org ---
Created attachment 35963
  --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=35963&action=edit
Tentative patch

[Bug tree-optimization/66851] support double reduction in parloops

[vries at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=66851

vries at gcc dot gnu.org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
           Keywords|                            |missed-optimization, patch
            Version|unknown                     |6.0
           Assignee|unassigned at gcc dot gnu.org      |vries at gcc dot gnu.org

--- Comment #2 from vries at gcc dot gnu.org ---
https://gcc.gnu.org/ml/gcc-patches/2015-07/msg01057.html

[Bug tree-optimization/66851] support double reduction in parloops

[vries at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=66851

--- Comment #3 from vries at gcc dot gnu.org ---
pinged: https://gcc.gnu.org/ml/gcc-patches/2015-07/msg02034.html

[Bug tree-optimization/66851] support double reduction in parloops

[vries at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=66851

--- Comment #4 from vries at gcc dot gnu.org ---
https://gcc.gnu.org/ml/gcc-cvs/2015-07/msg01090.html

Author: vries
Date: Tue Jul 28 07:54:04 2015
New Revision: 226300

URL: https://gcc.gnu.org/viewcvs?rev=226300&root=gcc&view=rev
Log:
Handle double reduction in parloops

2015-07-28  Tom de Vries  <tom@codesourcery.com>

        * tree-parloops.c (reduc_stmt_res): New function.
        (initialize_reductions, add_field_for_reduction)
        (create_phi_for_local_result, create_loads_for_reductions)
        (create_stores_for_reduction, build_new_reduction): Handle case that
        reduc_stmt is a phi.
        (gather_scalar_reductions): Allow double_reduc reductions.

        * gcc.dg/autopar/uns-outer-4.c: Remove xfail on scan for parallelizing
        outer loop.

        * testsuite/libgomp.c/uns-outer-4.c: New test.

Added:
    trunk/libgomp/testsuite/libgomp.c/uns-outer-4.c
Modified:
    trunk/gcc/ChangeLog
    trunk/gcc/testsuite/ChangeLog
    trunk/gcc/testsuite/gcc.dg/autopar/uns-outer-4.c
    trunk/gcc/tree-parloops.c
    trunk/libgomp/ChangeLog

[Bug tree-optimization/66851] support double reduction in parloops

[vries at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=66851

vries at gcc dot gnu.org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|UNCONFIRMED                 |RESOLVED
         Resolution|---                         |FIXED

--- Comment #5 from vries at gcc dot gnu.org ---
Patch and test-case committed, marking resolved-fixed.