[Bug debug/103836] New: '-fcompare-debug' failure (length) w/ -fopenacc --param openacc-kernels=decompose

[Bug debug/103836] New: '-fcompare-debug' failure (length) w/ -fopenacc --param openacc-kernels=decompose

[asolokha at gmx dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=103836

            Bug ID: 103836
           Summary: '-fcompare-debug' failure (length) w/ -fopenacc
                    --param openacc-kernels=decompose
           Product: gcc
           Version: 12.0
            Status: UNCONFIRMED
          Keywords: openacc
          Severity: normal
          Priority: P3
         Component: debug
          Assignee: unassigned at gcc dot gnu.org
          Reporter: asolokha at gmx dot com
  Target Milestone: ---

Created attachment 52061
  --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=52061&action=edit
diff -u o5cia6mf.*.gkd

g++ 12.0.0 20211219 snapshot (g:fcbf94a5be9e0c1ecad92da773a6632b86b7f70a) fails
-fcompare-debug check when compiling the following testcase w/, extracted from
gcc/testsuite/c-c++-common/goacc/nesting-1.c, w/ -fopenacc --param
openacc-kernels=decompose:

extern int i;

void
f_acc_kernels (void)
{
#pragma acc kernels
  {
#pragma acc loop
    for (i = 0; i < 2; ++i)
      ;
  }
}

% x86_64-unknown-linux-gnu-g++-12.0.0 -O1 -fcompare-debug -fopenacc --param
openacc-kernels=decompose -c o5cia6mf.c
x86_64-unknown-linux-gnu-g++-12.0.0: error: o5cia6mf.c: '-fcompare-debug'
failure (length)

Diff between two gkd files attached. I can reproduce the issue only w/ C++
front-end.

[Bug debug/103836] '-fcompare-debug' failure (length) w/ -fopenacc --param openacc-kernels=decompose

[jakub at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=103836

Jakub Jelinek <jakub at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |burnus at gcc dot gnu.org,
                   |                            |jakub at gcc dot gnu.org,
                   |                            |tschwinge at gcc dot gnu.org
             Status|UNCONFIRMED                 |NEW
     Ever confirmed|0                           |1
   Last reconfirmed|                            |2021-12-27

--- Comment #1 from Jakub Jelinek <jakub at gcc dot gnu.org> ---
 void foo ()
 {
+  # DEBUG BEGIN_STMT
   #pragma omp target oacc_kernels
     {
       int i.0;

+      # DEBUG BEGIN_STMT
+      # DEBUG BEGIN_STMT
       #pragma acc loop private(i.0) private(i)
       for (i.0 = 0; i.0 < 2; i.0 = i.0 + 1)
         {
           i = i.0;
+          # DEBUG BEGIN_STMT
         }
     }
 }

difference at gimplification time is ok, but
 void foo ()
 {
+  # DEBUG BEGIN_STMT
   #pragma omp target oacc_data_kernels
     {
       try
@@ -10,12 +11,18 @@ void foo ()
           {
             int i.0;

+            #pragma omp target oacc_parallel_kernels_gang_single async(-1)
num_gangs(1)
+              {
+                # DEBUG BEGIN_STMT
+                # DEBUG BEGIN_STMT
+              }
             #pragma omp target oacc_kernels async(-1)
               {
                 #pragma acc loop private(i.0) private(i)
                 for (i.0 = 0; i.0 < 2; i.0 = i.0 + 1)
                   {
                     i = i.0;
+                    # DEBUG BEGIN_STMT
                   }
               }
             __builtin_GOACC_wait (-2, 0);
from omp_oacc_kernels_decompose is not.  Debug stmts shouldn't affect
code-generation decisions.

[Bug middle-end/103836] '-fcompare-debug' failure (length) w/ -fopenacc --param openacc-kernels=decompose

[marxin at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=103836

Martin Liška <marxin at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |marxin at gcc dot gnu.org

--- Comment #2 from Martin Liška <marxin at gcc dot gnu.org> ---
Started with r11-8242-g3395dfc4da8ad1fc.

[Bug middle-end/103836] '-fcompare-debug' failure (length) w/ -fopenacc --param openacc-kernels=decompose

[cvs-commit at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=103836

--- Comment #3 from CVS Commits <cvs-commit at gcc dot gnu.org> ---
The master branch has been updated by Thomas Schwinge <tschwinge@gcc.gnu.org>:

https://gcc.gnu.org/g:c14ea6a72fb1ae66e3d32ac8329558497c6e4403

commit r12-7478-gc14ea6a72fb1ae66e3d32ac8329558497c6e4403
Author: Thomas Schwinge <thomas@codesourcery.com>
Date:   Wed Jan 19 14:04:42 2022 +0100

    Catch 'GIMPLE_DEBUG' misbehavior in OpenACC 'kernels' decomposition
[PR100400, PR103836, PR104061]

    Actually fixing it is a separate task, but it seems prudent to at least
catch
    it, and document via a few test cases.

            gcc/
            PR middle-end/100400
            PR middle-end/103836
            PR middle-end/104061
            * omp-oacc-kernels-decompose.cc (decompose_kernels_region_body):
            Catch 'GIMPLE_DEBUG'.
            gcc/testsuite/
            PR middle-end/100400
            PR middle-end/103836
            PR middle-end/104061
            * c-c++-common/goacc/kernels-decompose-pr100400-1-1.c: New.
            * c-c++-common/goacc/kernels-decompose-pr100400-1-2.c: New.
            * c-c++-common/goacc/kernels-decompose-pr100400-1-3.c: New.
            * c-c++-common/goacc/kernels-decompose-pr100400-1-4.c: New.
            * c-c++-common/goacc/kernels-decompose-pr103836-1-1.c: New.
            * c-c++-common/goacc/kernels-decompose-pr103836-1-2.c: New.
            * c-c++-common/goacc/kernels-decompose-pr103836-1-3.c: New.
            * c-c++-common/goacc/kernels-decompose-pr103836-1-4.c: New.
            * c-c++-common/goacc/kernels-decompose-pr104061-1-1.c: New.
            * c-c++-common/goacc/kernels-decompose-pr104061-1-2.c: New.
            * c-c++-common/goacc/kernels-decompose-pr104061-1-3.c: New.
            * c-c++-common/goacc/kernels-decompose-pr104061-1-4.c: New.