re PR middle-end/72781 (-Wuninitialized false positives in OpenMP code)

	PR middle-end/72781
	* omp-low.c (lower_lastprivate_clauses): Set TREE_NO_WARNING on the
	private vars for lastprivate and for linear iterator.

	* gcc.dg/gomp/pr72781.c: New test.

From-SVN: r239249

gcc/ChangeLog

 2016-08-08  Jakub Jelinek  <jakub@redhat.com>
 
+	PR middle-end/72781
+	* omp-low.c (lower_lastprivate_clauses): Set TREE_NO_WARNING on the
+	private vars for lastprivate and for linear iterator.
+
 	PR middle-end/68762
 	* omp-simd-clone.c: Include varasm.h.
 	(simd_clone_create): Copy over DECL_COMDAT, DECL_WEAK, DECL_EXTERNAL,

gcc/omp-low.c

@@ -5455,7 +5455,15 @@ lower_lastprivate_clauses (tree clauses, tree predicate, gimple_seq *stmt_list,
 	      new_var = lookup_decl (var, ctx->outer);
 	    }
 	  else
-	    new_var = lookup_decl (var, ctx);
+	    {
+	      new_var = lookup_decl (var, ctx);
+	      /* Avoid uninitialized warnings for lastprivate and
+		 for linear iterators.  */
+	      if (predicate
+		  && (OMP_CLAUSE_CODE (c) == OMP_CLAUSE_LASTPRIVATE
+		      || OMP_CLAUSE_LINEAR_NO_COPYIN (c)))
+		TREE_NO_WARNING (new_var) = 1;
+	    }
 
 	  if (simduid && DECL_HAS_VALUE_EXPR_P (new_var))
 	    {

gcc/testsuite/ChangeLog

 2016-08-08  Jakub Jelinek  <jakub@redhat.com>
 
+	PR middle-end/72781
+	* gcc.dg/gomp/pr72781.c: New test.
+
 	PR middle-end/68762
 	* g++.dg/vect/pr68762-1.cc: New test.
 	* g++.dg/vect/pr68762-2.cc: New test.

gcc/testsuite/gcc.dg/gomp/pr72781.c

+/* PR middle-end/72781 */
+/* { dg-do compile } */
+/* { dg-additional-options "-O2 -Wuninitialized" } */
+
+int u;
+
+void
+foo (int *p)
+{
+  int i;
+  #pragma omp for simd lastprivate(u) schedule (static, 32)	/* { dg-bogus "may be used uninitialized in this function" } */
+  for (i = 0; i < 1024; i++)
+    u = p[i];
+}
+
+void
+bar (int *p)
+{
+  int i;
+  #pragma omp taskloop simd lastprivate(u)	/* { dg-bogus "may be used uninitialized in this function" } */
+  for (i = 0; i < 1024; i++)
+    u = p[i];
+}