re PR middle-end/70550 (-Wuninitialized false positives in OpenMP code)

	PR middle-end/70550
	* tree.h (OMP_CLAUSE_FIRSTPRIVATE_IMPLICIT): Define.
	* gimplify.c (gimplify_adjust_omp_clauses_1): Set it for implicit
	firstprivate clauses.
	* omp-low.c (lower_send_clauses): Set TREE_NO_WARNING for
	OMP_CLAUSE_FIRSTPRIVATE_IMPLICIT !by_ref vars in task contexts.
	(lower_omp_target): Set TREE_NO_WARNING for
	non-addressable possibly uninitialized vars which are copied into
	addressable temporaries or copied for GOMP_MAP_FIRSTPRIVATE_INT.

	* c-c++-common/gomp/pr70550-1.c: New test.
	* c-c++-common/gomp/pr70550-2.c: New test.

From-SVN: r234779

7 files changed, 182 insertions, 2 deletions

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index d0ae429..e31d7cf 100644
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,15 @@
+2016-04-06  Jakub Jelinek  <jakub@redhat.com>
+
+	PR middle-end/70550
+	* tree.h (OMP_CLAUSE_FIRSTPRIVATE_IMPLICIT): Define.
+	* gimplify.c (gimplify_adjust_omp_clauses_1): Set it for implicit
+	firstprivate clauses.
+	* omp-low.c (lower_send_clauses): Set TREE_NO_WARNING for
+	OMP_CLAUSE_FIRSTPRIVATE_IMPLICIT !by_ref vars in task contexts.
+	(lower_omp_target): Set TREE_NO_WARNING for
+	non-addressable possibly uninitialized vars which are copied into
+	addressable temporaries or copied for GOMP_MAP_FIRSTPRIVATE_INT.
+
 2016-04-05  John David Anglin  <danglin@gcc.gnu.org>
 
 	* config/pa/predicates.md (integer_store_memory_operand): Accept
diff --git a/gcc/gimplify.c b/gcc/gimplify.c
index b9757db..f29d608 100644
--- a/gcc/gimplify.c
+++ b/gcc/gimplify.c
@@ -7742,6 +7742,8 @@ gimplify_adjust_omp_clauses_1 (splay_tree_node n, void *data)
 	   && (flags & GOVD_WRITTEN) == 0
 	   && omp_shared_to_firstprivate_optimizable_decl_p (decl))
     OMP_CLAUSE_SHARED_READONLY (clause) = 1;
+  else if (code == OMP_CLAUSE_FIRSTPRIVATE && (flags & GOVD_EXPLICIT) == 0)
+    OMP_CLAUSE_FIRSTPRIVATE_IMPLICIT (clause) = 1;
   else if (code == OMP_CLAUSE_MAP && (flags & GOVD_MAP_0LEN_ARRAY) != 0)
     {
       tree nc = build_omp_clause (input_location, OMP_CLAUSE_MAP);
diff --git a/gcc/omp-low.c b/gcc/omp-low.c
index 3fd6eb3..52a8005 100644
--- a/gcc/omp-low.c
+++ b/gcc/omp-low.c
@@ -6107,8 +6107,15 @@ lower_send_clauses (tree clauses, gimple_seq *ilist, gimple_seq *olist,
 
       switch (OMP_CLAUSE_CODE (c))
 	{
-	case OMP_CLAUSE_PRIVATE:
 	case OMP_CLAUSE_FIRSTPRIVATE:
+	  if (OMP_CLAUSE_FIRSTPRIVATE_IMPLICIT (c)
+	      && !by_ref
+	      && is_task_ctx (ctx))
+	    TREE_NO_WARNING (var) = 1;
+	  do_in = true;
+	  break;
+
+	case OMP_CLAUSE_PRIVATE:
 	case OMP_CLAUSE_COPYIN:
 	case OMP_CLAUSE__LOOPTEMP_:
 	  do_in = true;
@@ -16083,7 +16090,16 @@ lower_omp_target (gimple_stmt_iterator *gsi_p, omp_context *ctx)
 			|| map_kind == GOMP_MAP_POINTER
 			|| map_kind == GOMP_MAP_TO_PSET
 			|| map_kind == GOMP_MAP_FORCE_DEVICEPTR)
-		      gimplify_assign (avar, var, &ilist);
+		      {
+			/* If we need to initialize a temporary
+			   with VAR because it is not addressable, and
+			   the variable hasn't been initialized yet, then
+			   we'll get a warning for the store to avar.
+			   Don't warn in that case, the mapping might
+			   be implicit.  */
+			TREE_NO_WARNING (var) = 1;
+			gimplify_assign (avar, var, &ilist);
+		      }
 		    avar = build_fold_addr_expr (avar);
 		    gimplify_assign (x, avar, &ilist);
 		    if ((GOMP_MAP_COPY_FROM_P (map_kind)
@@ -16252,6 +16268,8 @@ lower_omp_target (gimple_stmt_iterator *gsi_p, omp_context *ctx)
 		tree t = var;
 		if (is_reference (var))
 		  t = build_simple_mem_ref (var);
+		else if (OMP_CLAUSE_FIRSTPRIVATE_IMPLICIT (c))
+		  TREE_NO_WARNING (var) = 1;
 		if (TREE_CODE (type) != POINTER_TYPE)
 		  t = fold_convert (pointer_sized_int_node, t);
 		t = fold_convert (TREE_TYPE (x), t);
@@ -16263,6 +16281,8 @@ lower_omp_target (gimple_stmt_iterator *gsi_p, omp_context *ctx)
 	      {
 		tree avar = create_tmp_var (TREE_TYPE (var));
 		mark_addressable (avar);
+		if (OMP_CLAUSE_FIRSTPRIVATE_IMPLICIT (c))
+		  TREE_NO_WARNING (var) = 1;
 		gimplify_assign (avar, var, &ilist);
 		avar = build_fold_addr_expr (avar);
 		gimplify_assign (x, avar, &ilist);
diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog
index 2e5954c..5c4b95f 100644
--- a/gcc/testsuite/ChangeLog
+++ b/gcc/testsuite/ChangeLog
@@ -1,3 +1,9 @@
+2016-04-06  Jakub Jelinek  <jakub@redhat.com>
+
+	PR middle-end/70550
+	* c-c++-common/gomp/pr70550-1.c: New test.
+	* c-c++-common/gomp/pr70550-2.c: New test.
+
 2016-04-05  Nathan Sidwell  <nathan@acm.org>
 
 	PR c++/70512
diff --git a/gcc/testsuite/c-c++-common/gomp/pr70550-1.c b/gcc/testsuite/c-c++-common/gomp/pr70550-1.c
new file mode 100644
index 0000000..493d417
--- /dev/null
+++ b/gcc/testsuite/c-c++-common/gomp/pr70550-1.c
@@ -0,0 +1,81 @@
+/* PR middle-end/70550 */
+/* { dg-do compile } */
+/* { dg-additional-options "-Wuninitialized" } */
+
+#ifdef __SIZEOF_INT128__
+typedef __int128 T;
+#else
+typedef long long T;
+#endif
+
+void bar (T);
+#pragma omp declare target (bar)
+
+void
+foo (void)
+{
+  {
+    int i;
+    #pragma omp target defaultmap(tofrom:scalar)	/* { dg-bogus "is used uninitialized in this function" } */
+    {
+      i = 26;
+      bar (i);
+    }
+  }
+  {
+    T j;
+    #pragma omp target defaultmap(tofrom:scalar)	/* { dg-bogus "is used uninitialized in this function" } */
+    {
+      j = 37;
+      bar (j);
+    }
+  }
+  {
+    int i;
+    #pragma omp target					/* { dg-bogus "is used uninitialized in this function" } */
+    {
+      i = 26;
+      bar (i);
+    }
+  }
+  {
+    T j;
+    #pragma omp target					/* { dg-bogus "is used uninitialized in this function" } */
+    {
+      j = 37;
+      bar (j);
+    }
+  }
+  {
+    int i;
+    #pragma omp target firstprivate (i)			/* { dg-warning "is used uninitialized in this function" } */
+    {
+      i = 26;
+      bar (i);
+    }
+  }
+  {
+    T j;
+    #pragma omp target firstprivate (j)			/* { dg-warning "is used uninitialized in this function" } */
+    {
+      j = 37;
+      bar (j);
+    }
+  }
+  {
+    int i;
+    #pragma omp target private (i)			/* { dg-bogus "is used uninitialized in this function" } */
+    {
+      i = 26;
+      bar (i);
+    }
+  }
+  {
+    T j;
+    #pragma omp target private (j)			/* { dg-bogus "is used uninitialized in this function" } */
+    {
+      j = 37;
+      bar (j);
+    }
+  }
+}
diff --git a/gcc/testsuite/c-c++-common/gomp/pr70550-2.c b/gcc/testsuite/c-c++-common/gomp/pr70550-2.c
new file mode 100644
index 0000000..31c34da
--- /dev/null
+++ b/gcc/testsuite/c-c++-common/gomp/pr70550-2.c
@@ -0,0 +1,55 @@
+/* PR middle-end/70550 */
+/* { dg-do compile } */
+/* { dg-additional-options "-Wuninitialized" } */
+
+void bar (int);
+
+void
+foo (void)
+{
+  int i, j, k, l, m, n, o, p, q;
+  #pragma omp task				/* { dg-bogus "is used uninitialized in this function" } */
+  {
+    i = 2;
+    bar (i);
+  }
+  #pragma omp taskloop				/* { dg-bogus "is used uninitialized in this function" } */
+  for (j = 0; j < 10; j++)
+    {
+      k = 7;
+      bar (k);
+    }
+  #pragma omp task firstprivate (l)		/* { dg-warning "is used uninitialized in this function" } */
+  {
+    l = 2;
+    bar (l);
+  }
+  #pragma omp taskloop firstprivate (m)		/* { dg-warning "is used uninitialized in this function" } */
+  for (j = 0; j < 10; j++)
+    {
+      m = 7;
+      bar (m);
+    }
+  #pragma omp task shared (n)			/* { dg-bogus "is used uninitialized in this function" } */
+  {
+    n = 2;
+    bar (n);
+  }
+  #pragma omp taskloop shared (o)		/* { dg-bogus "is used uninitialized in this function" } */
+  for (j = 0; j < 10; j++)
+    {
+      o = 7;
+      bar (o);
+    }
+  #pragma omp task private (p)			/* { dg-bogus "is used uninitialized in this function" } */
+  {
+    p = 2;
+    bar (p);
+  }
+  #pragma omp taskloop shared (q)		/* { dg-bogus "is used uninitialized in this function" } */
+  for (j = 0; j < 10; j++)
+    {
+      q = 7;
+      bar (q);
+    }
+}
diff --git a/gcc/tree.h b/gcc/tree.h
index 544a6a1..fa70596 100644
--- a/gcc/tree.h
+++ b/gcc/tree.h
@@ -1430,6 +1430,10 @@ extern void protected_set_expr_location (tree, location_t);
 #define OMP_CLAUSE_PRIVATE_TASKLOOP_IV(NODE) \
   TREE_PROTECTED (OMP_CLAUSE_SUBCODE_CHECK (NODE, OMP_CLAUSE_PRIVATE))
 
+/* True on a FIRSTPRIVATE clause if it has been added implicitly.  */
+#define OMP_CLAUSE_FIRSTPRIVATE_IMPLICIT(NODE) \
+  (OMP_CLAUSE_SUBCODE_CHECK (NODE, OMP_CLAUSE_FIRSTPRIVATE)->base.public_flag)
+
 /* True on a LASTPRIVATE clause if a FIRSTPRIVATE clause for the same
    decl is present in the chain.  */
 #define OMP_CLAUSE_LASTPRIVATE_FIRSTPRIVATE(NODE) \