omp-low.c (lower_oacc_reductions): Adjust variable lookup to use maybe_lookup_decl...

2016-08-17  Chung-Lin Tang  <cltang@codesourcery.com>

	* omp-low.c (lower_oacc_reductions): Adjust variable lookup to use
	maybe_lookup_decl, to handle nested acc loop directives.

	testsuite/
	* c-c++-common/goacc/reduction-6.c: New testcase.

From-SVN: r239530

gcc/ChangeLog

@@ -1,3 +1,8 @@
+2016-08-17  Chung-Lin Tang  <cltang@codesourcery.com>
+
+	* omp-low.c (lower_oacc_reductions): Adjust variable lookup to use
+	maybe_lookup_decl, to handle nested acc loop directives.
+
 2016-08-17  Richard Biener  <rguenther@suse.de>
 
 	PR tree-optimization/76490

gcc/omp-low.c

@@ -5660,10 +5660,19 @@ lower_oacc_reductions (location_t loc, tree clauses, tree level, bool inner,
 		outgoing = var;
 		incoming = omp_reduction_init_op (loc, rcode, type);
 	      }
-	    else if (ctx->outer)
-	      incoming = outgoing = lookup_decl (orig, ctx->outer);
 	    else
-	      incoming = outgoing = orig;
+	      {
+		/* Try to look at enclosing contexts for reduction var,
+		   use original if no mapping found.  */
+		tree t = NULL_TREE;
+		omp_context *c = ctx->outer;
+		while (c && !t)
+		  {
+		    t = maybe_lookup_decl (orig, c);
+		    c = c->outer;
+		  }
+		incoming = outgoing = (t ? t : orig);
+	      }
 	      
 	  has_outer_reduction:;
 	  }

gcc/testsuite/ChangeLog

@@ -1,3 +1,7 @@
+2016-08-17  Chung-Lin Tang  <cltang@codesourcery.com>
+
+	* c-c++-common/goacc/reduction-6.c: New testcase.
+
 2016-08-17  Richard Biener  <rguenther@suse.de>
 
 	PR tree-optimization/76490

gcc/testsuite/c-c++-common/goacc/reduction-6.c

@@ -0,0 +1,58 @@
+/* Check if different occurences of the reduction clause on
+   OpenACC loop nests will compile.  */
+
+int foo (int N)
+{
+  int a = 0, b = 0, c = 0, d = 0, e = 0;
+
+  #pragma acc parallel
+  {
+    #pragma acc loop
+    for (int i = 0; i < N; i++)
+      {
+        #pragma acc loop reduction(+:a)
+	for (int j = 0; j < N; j++)
+	  a += 1;
+      }
+  }
+
+  #pragma acc parallel
+  {
+    #pragma acc loop reduction(+:b)
+    for (int i = 0; i < N; i++)
+      {
+        #pragma acc loop
+	for (int j = 0; j < N; j++)
+	  b += 1;
+      }
+  }
+
+  #pragma acc parallel
+  {
+    #pragma acc loop reduction(+:c)
+    for (int i = 0; i < N; i++)
+      {
+        #pragma acc loop reduction(+:c)
+	for (int j = 0; j < N; j++)
+	  c += 1;
+      }
+  }
+
+  #pragma acc parallel loop
+  for (int i = 0; i < N; i++)
+    {
+      #pragma acc loop reduction(+:d)
+      for (int j = 0; j < N; j++)
+	d += 1;
+    }
+
+  #pragma acc parallel loop reduction(+:e)
+  for (int i = 0; i < N; i++)
+    {
+      #pragma acc loop reduction(+:e)
+      for (int j = 0; j < N; j++)
+	e += 1;
+    }
+
+  return a + b + c + d + e;
+}