fix PR68550: do not handle ISL loop peeled statements

In case ISL did some loop peeling, like this:

  S_8(0);
  for (int c1 = 1; c1 <= 5; c1 += 1) {
    S_8(c1);
  }
  S_8(6);

we should not copy loop-phi nodes in S_8(0) or in S_8(6).

	PR tree-optimization/68550
	* graphite-isl-ast-to-gimple.c (copy_loop_phi_nodes): Add dump.
	(copy_bb_and_scalar_dependences): Do not code generate loop peeled
	statements.

	* gfortran.dg/graphite/pr68550-1.f90: New.
	* gfortran.dg/graphite/pr68550-2.f90: New.

git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@231206 138bc75d-0d04-0410-961f-82ee72b054a4

1 files changed, 26 insertions, 0 deletions

diff --git a/gcc/graphite-isl-ast-to-gimple.c b/gcc/graphite-isl-ast-to-gimple.c
index bfce3169549..3139f302ff0 100644
--- a/gcc/graphite-isl-ast-to-gimple.c
+++ b/gcc/graphite-isl-ast-to-gimple.c
@@ -2096,6 +2096,12 @@ translate_isl_ast_to_gimple::copy_loop_phi_nodes (basic_block bb,
       codegen_error = !copy_loop_phi_args (phi, ibp_old_bb, new_phi,
 					  ibp_new_bb, true);
       update_stmt (new_phi);
+
+      if (dump_file)
+	{
+	  fprintf (dump_file, "[codegen] creating loop-phi node: ");
+	  print_gimple_stmt (dump_file, new_phi, 0, 0);
+	}
     }
 
   return true;
@@ -2894,6 +2900,26 @@ translate_isl_ast_to_gimple::copy_bb_and_scalar_dependences (basic_block bb,
 	      return NULL;
 	    }
 
+	  /* In case ISL did some loop peeling, like this:
+
+	       S_8(0);
+	       for (int c1 = 1; c1 <= 5; c1 += 1) {
+	         S_8(c1);
+	       }
+	       S_8(6);
+
+	     there should be no loop-phi nodes in S_8(0).
+
+	     FIXME: We need to reason about dynamic instances of S_8, i.e., the
+	     values of all scalar variables: for the moment we instantiate only
+	     SCEV analyzable expressions on the iteration domain, and we need to
+	     extend that to reductions that cannot be analyzed by SCEV.  */
+	  if (!bb_in_sese_p (phi_bb, region->if_region->true_region->region))
+	    {
+	      codegen_error = true;
+	      return NULL;
+	    }
+
 	  if (dump_file)
 	    fprintf (dump_file, "[codegen] bb_%d contains loop phi nodes.\n",
 		     bb->index);