OpenMP: Add -Wopenmp and use it

The new warning has two purposes: First, it makes clearer to the
user that it is about OpenMP and, secondly and more importantly,
it permits to use -Wno-openmp.

The newly added -Wopenmp is enabled by default and replaces the
'0' (always warning) in several OpenMP-related warning calls.
For code shared with OpenACC, it only uses OPT_Wopenmp for
'flag_openmp | flag_openmp_simd'.

gcc/c-family/ChangeLog:

	* c.opt (Wopenmp): Add, enable by default.

gcc/c/ChangeLog:

	* c-parser.cc (c_parser_omp_clause_num_threads,
	c_parser_omp_clause_num_tasks, c_parser_omp_clause_grainsize,
	c_parser_omp_clause_priority, c_parser_omp_clause_schedule,
	c_parser_omp_clause_num_teams, c_parser_omp_clause_thread_limit,
	c_parser_omp_clause_dist_schedule, c_parser_omp_depobj,
	c_parser_omp_scan_loop_body, c_parser_omp_assumption_clauses):
	Add OPT_Wopenmp to warning_at.

gcc/cp/ChangeLog:

	* parser.cc (cp_parser_omp_clause_dist_schedule,
	cp_parser_omp_scan_loop_body, cp_parser_omp_assumption_clauses,
	cp_parser_omp_depobj): Add OPT_Wopenmp to warning_at.
	* semantics.cc (finish_omp_clauses): Likewise.

gcc/ChangeLog:

	* doc/invoke.texi (-Wopenmp): Add.
	* gimplify.cc (gimplify_omp_for): Add OPT_Wopenmp to warning_at.
	* omp-expand.cc (expand_omp_ordered_sink): Likewise.
	* omp-general.cc (omp_check_context_selector): Likewise.
	* omp-low.cc (scan_omp_for, check_omp_nesting_restrictions,
	lower_omp_ordered_clauses): Likewise.
	* omp-simd-clone.cc (simd_clone_clauses_extract): Likewise.

gcc/fortran/ChangeLog:

	* lang.opt (Wopenmp): Add, enabled by dafault and documented in C.
	* openmp.cc (gfc_match_omp_declare_target, resolve_positive_int_expr,
	resolve_nonnegative_int_expr, resolve_omp_clauses,
	gfc_resolve_omp_do_blocks): Use OPT_Wopenmp with gfc_warning{,_now}.

12 files changed, 105 insertions, 72 deletions

diff --git a/gcc/c-family/c.opt b/gcc/c-family/c.opt
index 3848f37..c3d45a6 100644
--- a/gcc/c-family/c.opt
+++ b/gcc/c-family/c.opt
@@ -1175,6 +1175,10 @@ Wopenacc-parallelism
 C C++ Var(warn_openacc_parallelism) Warning
 Warn about potentially suboptimal choices related to OpenACC parallelism.
 
+Wopenmp
+C ObjC C++ ObjC++ Warning Var(warn_openmp) Init(1)
+Warn about suspicious OpenMP code
+
 Wopenmp-simd
 C C++ Var(warn_openmp_simd) Warning LangEnabledBy(C C++,Wall)
 Warn if a simd directive is overridden by the vectorizer cost model.
diff --git a/gcc/c/c-parser.cc b/gcc/c/c-parser.cc
index 989c050..df9a079 100644
--- a/gcc/c/c-parser.cc
+++ b/gcc/c/c-parser.cc
@@ -16071,7 +16071,7 @@ c_parser_omp_clause_num_threads (c_parser *parser, tree list)
       protected_set_expr_location (c, expr_loc);
       if (c == boolean_true_node)
 	{
-	  warning_at (expr_loc, 0,
+	  warning_at (expr_loc, OPT_Wopenmp,
 		      "%<num_threads%> value must be positive");
 	  t = integer_one_node;
 	}
@@ -16132,7 +16132,8 @@ c_parser_omp_clause_num_tasks (c_parser *parser, tree list)
 	SET_EXPR_LOCATION (c, expr_loc);
       if (c == boolean_true_node)
 	{
-	  warning_at (expr_loc, 0, "%<num_tasks%> value must be positive");
+	  warning_at (expr_loc, OPT_Wopenmp,
+		      "%<num_tasks%> value must be positive");
 	  t = integer_one_node;
 	}
 
@@ -16193,7 +16194,8 @@ c_parser_omp_clause_grainsize (c_parser *parser, tree list)
 	SET_EXPR_LOCATION (c, expr_loc);
       if (c == boolean_true_node)
 	{
-	  warning_at (expr_loc, 0, "%<grainsize%> value must be positive");
+	  warning_at (expr_loc, OPT_Wopenmp,
+		      "%<grainsize%> value must be positive");
 	  t = integer_one_node;
 	}
 
@@ -16241,7 +16243,8 @@ c_parser_omp_clause_priority (c_parser *parser, tree list)
 	SET_EXPR_LOCATION (c, expr_loc);
       if (c == boolean_true_node)
 	{
-	  warning_at (expr_loc, 0, "%<priority%> value must be non-negative");
+	  warning_at (expr_loc, OPT_Wopenmp,
+		      "%<priority%> value must be non-negative");
 	  t = integer_one_node;
 	}
 
@@ -17383,7 +17386,7 @@ c_parser_omp_clause_schedule (c_parser *parser, tree list)
 	  protected_set_expr_location (s, loc);
 	  if (s == boolean_true_node)
 	    {
-	      warning_at (loc, 0,
+	      warning_at (loc, OPT_Wopenmp,
 			  "chunk size value must be positive");
 	      t = integer_one_node;
 	    }
@@ -17545,7 +17548,8 @@ c_parser_omp_clause_num_teams (c_parser *parser, tree list)
       protected_set_expr_location (c, upper_loc);
       if (c == boolean_true_node)
 	{
-	  warning_at (upper_loc, 0, "%<num_teams%> value must be positive");
+	  warning_at (upper_loc, OPT_Wopenmp,
+		      "%<num_teams%> value must be positive");
 	  upper = integer_one_node;
 	}
       if (lower)
@@ -17555,15 +17559,17 @@ c_parser_omp_clause_num_teams (c_parser *parser, tree list)
 	  protected_set_expr_location (c, lower_loc);
 	  if (c == boolean_true_node)
 	    {
-	      warning_at (lower_loc, 0, "%<num_teams%> value must be positive");
+	      warning_at (lower_loc, OPT_Wopenmp,
+			  "%<num_teams%> value must be positive");
 	      lower = NULL_TREE;
 	    }
 	  else if (TREE_CODE (lower) == INTEGER_CST
 		   && TREE_CODE (upper) == INTEGER_CST
 		   && tree_int_cst_lt (upper, lower))
 	    {
-	      warning_at (lower_loc, 0, "%<num_teams%> lower bound %qE bigger "
-					"than upper bound %qE", lower, upper);
+	      warning_at (lower_loc, OPT_Wopenmp,
+			  "%<num_teams%> lower bound %qE bigger than upper "
+			  "bound %qE", lower, upper);
 	      lower = NULL_TREE;
 	    }
 	}
@@ -17610,7 +17616,8 @@ c_parser_omp_clause_thread_limit (c_parser *parser, tree list)
       protected_set_expr_location (c, expr_loc);
       if (c == boolean_true_node)
 	{
-	  warning_at (expr_loc, 0, "%<thread_limit%> value must be positive");
+	  warning_at (expr_loc, OPT_Wopenmp,
+		      "%<thread_limit%> value must be positive");
 	  t = integer_one_node;
 	}
 
@@ -18840,7 +18847,7 @@ c_parser_omp_clause_dist_schedule (c_parser *parser, tree list)
   /* check_no_duplicate_clause (list, OMP_CLAUSE_DIST_SCHEDULE,
 				"dist_schedule"); */
   if (omp_find_clause (list, OMP_CLAUSE_DIST_SCHEDULE))
-    warning_at (loc, 0, "too many %qs clauses", "dist_schedule");
+    warning_at (loc, OPT_Wopenmp, "too many %qs clauses", "dist_schedule");
   if (t == error_mark_node)
     return list;
 
@@ -21680,7 +21687,7 @@ c_parser_omp_depobj (c_parser *parser)
 		       && !operand_equal_p (destobj, depobj,
 					    OEP_MATCH_SIDE_EFFECTS
 					    | OEP_LEXICOGRAPHIC))
-		warning_at (EXPR_LOC_OR_LOC (destobj, c_loc), 0,
+		warning_at (EXPR_LOC_OR_LOC (destobj, c_loc), OPT_Wopenmp,
 			    "the %<destroy%> expression %qE should be the same "
 			    "as the %<depobj%> argument %qE", destobj, depobj);
 	      c_parens.skip_until_found_close (parser);
@@ -21915,7 +21922,7 @@ c_parser_omp_scan_loop_body (c_parser *parser, bool open_brace_parsed)
     substmt = c_parser_omp_structured_block_sequence (parser, PRAGMA_OMP_SCAN);
   else
     {
-      warning_at (c_parser_peek_token (parser)->location, 0,
+      warning_at (c_parser_peek_token (parser)->location, OPT_Wopenmp,
 		  "%<#pragma omp scan%> with zero preceding executable "
 		  "statements");
       substmt = build_empty_stmt (loc);
@@ -21963,8 +21970,9 @@ c_parser_omp_scan_loop_body (c_parser *parser, bool open_brace_parsed)
   else
     {
       if (found_scan)
-	warning_at (loc, 0, "%<#pragma omp scan%> with zero succeeding "
-			    "executable statements");
+	warning_at (loc, OPT_Wopenmp,
+		    "%<#pragma omp scan%> with zero succeeding executable "
+		    "statements");
       substmt = build_empty_stmt (loc);
     }
   substmt = build2 (OMP_SCAN, void_type_node, substmt, clauses);
@@ -26270,7 +26278,7 @@ c_parser_omp_assumption_clauses (c_parser *parser, bool is_assume)
 	}
       else if (startswith (p, "ext_"))
 	{
-	  warning_at (cloc, 0, "unknown assumption clause %qs", p);
+	  warning_at (cloc, OPT_Wopenmp, "unknown assumption clause %qs", p);
 	  c_parser_consume_token (parser);
 	  if (c_parser_next_token_is (parser, CPP_OPEN_PAREN))
 	    {
diff --git a/gcc/cp/parser.cc b/gcc/cp/parser.cc
index e4e2fea..2464d1a 100644
--- a/gcc/cp/parser.cc
+++ b/gcc/cp/parser.cc
@@ -41161,7 +41161,7 @@ cp_parser_omp_clause_dist_schedule (cp_parser *parser, tree list,
   /* check_no_duplicate_clause (list, OMP_CLAUSE_DIST_SCHEDULE,
 				"dist_schedule", location); */
   if (omp_find_clause (list, OMP_CLAUSE_DIST_SCHEDULE))
-    warning_at (location, 0, "too many %qs clauses", "dist_schedule");
+    warning_at (location, OPT_Wopenmp, "too many %qs clauses", "dist_schedule");
   OMP_CLAUSE_CHAIN (c) = list;
   return c;
 
@@ -43233,7 +43233,7 @@ cp_parser_omp_depobj (cp_parser *parser, cp_token *pragma_tok)
 		  && destobj != error_mark_node
 		  && !operand_equal_p (destobj, depobj, OEP_MATCH_SIDE_EFFECTS
 							| OEP_LEXICOGRAPHIC))
-		warning_at (EXPR_LOC_OR_LOC (destobj, c_loc), 0,
+		warning_at (EXPR_LOC_OR_LOC (destobj, c_loc), OPT_Wopenmp,
 			    "the %<destroy%> expression %qE should be the same "
 			    "as the %<depobj%> argument %qE", destobj, depobj);
 	      if (!c_parens.require_close (parser))
@@ -44106,8 +44106,9 @@ cp_parser_omp_scan_loop_body (cp_parser *parser)
     substmt = cp_parser_omp_structured_block_sequence (parser, PRAGMA_OMP_SCAN);
   else
     {
-      warning_at (tok->location, 0, "%<#pragma omp scan%> with zero preceding "
-				    "executable statements");
+      warning_at (tok->location, OPT_Wopenmp,
+		  "%<#pragma omp scan%> with zero preceding executable "
+		  "statements");
       substmt = build_empty_stmt (tok->location);
     }
   substmt = build2 (OMP_SCAN, void_type_node, substmt, NULL_TREE);
@@ -44153,8 +44154,9 @@ cp_parser_omp_scan_loop_body (cp_parser *parser)
   else
     {
       if (found_scan)
-	warning_at (tok->location, 0, "%<#pragma omp scan%> with zero "
-				      "succeeding executable statements");
+	warning_at (tok->location, OPT_Wopenmp,
+		    "%<#pragma omp scan%> with zero succeeding executable "
+		    "statements");
       substmt = build_empty_stmt (tok->location);
     }
   substmt = build2_loc (tok->location, OMP_SCAN, void_type_node, substmt,
@@ -47851,7 +47853,7 @@ cp_parser_omp_assumption_clauses (cp_parser *parser, cp_token *pragma_tok,
 	}
       else if (startswith (p, "ext_"))
 	{
-	  warning_at (cloc, 0, "unknown assumption clause %qs", p);
+	  warning_at (cloc, OPT_Wopenmp, "unknown assumption clause %qs", p);
 	  cp_lexer_consume_token (parser->lexer);
 	  if (cp_lexer_next_token_is (parser->lexer, CPP_OPEN_PAREN))
 	    for (size_t n = cp_parser_skip_balanced_tokens (parser, 1) - 1;
diff --git a/gcc/cp/semantics.cc b/gcc/cp/semantics.cc
index f0a8372..3bf5864 100644
--- a/gcc/cp/semantics.cc
+++ b/gcc/cp/semantics.cc
@@ -7561,7 +7561,9 @@ finish_omp_clauses (tree clauses, enum c_omp_region_type ort)
 				      "positive");
 			  break;
 			default:
-			  warning_at (OMP_CLAUSE_LOCATION (c), 0,
+			  warning_at (OMP_CLAUSE_LOCATION (c),
+				      (flag_openmp || flag_openmp_simd)
+				      ? OPT_Wopenmp : 0,
 				      "%qs value must be positive",
 				      omp_clause_code_name
 				      [OMP_CLAUSE_CODE (c)]);
@@ -7596,7 +7598,7 @@ finish_omp_clauses (tree clauses, enum c_omp_region_type ort)
 		      if (TREE_CODE (t) == INTEGER_CST
 			  && tree_int_cst_sgn (t) != 1)
 			{
-			  warning_at (OMP_CLAUSE_LOCATION (c), 0,
+			  warning_at (OMP_CLAUSE_LOCATION (c), OPT_Wopenmp,
 				      "%qs value must be positive",
 				      omp_clause_code_name
 				      [OMP_CLAUSE_CODE (c)]);
@@ -7610,7 +7612,7 @@ finish_omp_clauses (tree clauses, enum c_omp_region_type ort)
 			  && TREE_CODE (upper) == INTEGER_CST
 			  && tree_int_cst_lt (upper, t))
 			{
-			  warning_at (OMP_CLAUSE_LOCATION (c), 0,
+			  warning_at (OMP_CLAUSE_LOCATION (c), OPT_Wopenmp,
 				      "%<num_teams%> lower bound %qE bigger "
 				      "than upper bound %qE", t, upper);
 			  t = NULL_TREE;
@@ -7643,7 +7645,7 @@ finish_omp_clauses (tree clauses, enum c_omp_region_type ort)
 		  if (TREE_CODE (t) == INTEGER_CST
 		      && tree_int_cst_sgn (t) != 1)
 		  {
-		    warning_at (OMP_CLAUSE_LOCATION (c), 0,
+		    warning_at (OMP_CLAUSE_LOCATION (c), OPT_Wopenmp,
 			      "chunk size value must be positive");
 		    t = integer_one_node;
 		  }
@@ -7739,7 +7741,7 @@ finish_omp_clauses (tree clauses, enum c_omp_region_type ort)
 		  if (TREE_CODE (t) == INTEGER_CST
 		      && tree_int_cst_sgn (t) != 1)
 		    {
-		      warning_at (OMP_CLAUSE_LOCATION (c), 0,
+		      warning_at (OMP_CLAUSE_LOCATION (c), OPT_Wopenmp,
 				  "%<thread_limit%> value must be positive");
 		      t = integer_one_node;
 		    }
@@ -7935,7 +7937,7 @@ finish_omp_clauses (tree clauses, enum c_omp_region_type ort)
 	    }
 	  else if (bitmap_bit_p (&aligned_head, DECL_UID (t)))
 	    {
-	      warning_at (OMP_CLAUSE_LOCATION (c), 0,
+	      warning_at (OMP_CLAUSE_LOCATION (c), OPT_Wopenmp,
 			"%qD appears more than once in %<allocate%> clauses",
 			t);
 	      remove = true;
@@ -8707,7 +8709,7 @@ finish_omp_clauses (tree clauses, enum c_omp_region_type ort)
 		  if (TREE_CODE (t) == INTEGER_CST
 		      && tree_int_cst_sgn (t) != 1)
 		    {
-		      warning_at (OMP_CLAUSE_LOCATION (c), 0,
+		      warning_at (OMP_CLAUSE_LOCATION (c), OPT_Wopenmp,
 				  "%<grainsize%> value must be positive");
 		      t = integer_one_node;
 		    }
@@ -8737,7 +8739,7 @@ finish_omp_clauses (tree clauses, enum c_omp_region_type ort)
 		  if (TREE_CODE (t) == INTEGER_CST
 		      && tree_int_cst_sgn (t) == -1)
 		    {
-		      warning_at (OMP_CLAUSE_LOCATION (c), 0,
+		      warning_at (OMP_CLAUSE_LOCATION (c), OPT_Wopenmp,
 				  "%<priority%> value must be non-negative");
 		      t = integer_one_node;
 		    }
diff --git a/gcc/doc/invoke.texi b/gcc/doc/invoke.texi
index 7801f80..23e2b74 100644
--- a/gcc/doc/invoke.texi
+++ b/gcc/doc/invoke.texi
@@ -383,7 +383,7 @@ Objective-C and Objective-C++ Dialects}.
 -Wnormalized=@r{[}none@r{|}id@r{|}nfc@r{|}nfkc@r{]}
 -Wnull-dereference  -Wno-odr
 -Wopenacc-parallelism
--Wopenmp-simd
+-Wopenmp -Wopenmp-simd
 -Wno-overflow  -Woverlength-strings  -Wno-override-init-side-effects
 -Wpacked  -Wno-packed-bitfield-compat  -Wpacked-not-aligned  -Wpadded
 -Wparentheses  -Wno-pedantic-ms-format
@@ -9957,6 +9957,11 @@ Enabled by default.
 @item -Wopenacc-parallelism
 Warn about potentially suboptimal choices related to OpenACC parallelism.
 
+@opindex Wopenmp
+@opindex Wno-openmp
+@item -Wno-openmp
+Warn about suspicious OpenMP code.
+
 @opindex Wopenmp-simd
 @opindex Wno-openmp-simd
 @item -Wopenmp-simd
diff --git a/gcc/fortran/lang.opt b/gcc/fortran/lang.opt
index 08c7539..adcfc28 100644
--- a/gcc/fortran/lang.opt
+++ b/gcc/fortran/lang.opt
@@ -289,6 +289,10 @@ Wopenacc-parallelism
 Fortran
 ; Documented in C
 
+Wopenmp
+Fortran
+; Documented in C
+
 Wopenmp-simd
 Fortran
 ; Documented in C
diff --git a/gcc/fortran/openmp.cc b/gcc/fortran/openmp.cc
index b9ac611..794df19 100644
--- a/gcc/fortran/openmp.cc
+++ b/gcc/fortran/openmp.cc
@@ -21,6 +21,7 @@ along with GCC; see the file COPYING3.  If not see
 #include "config.h"
 #include "system.h"
 #include "coretypes.h"
+#include "options.h"
 #include "gfortran.h"
 #include "arith.h"
 #include "match.h"
@@ -5563,8 +5564,9 @@ gfc_match_omp_declare_target (void)
       && !c->lists[OMP_LIST_ENTER]
       && !c->lists[OMP_LIST_TO]
       && !c->lists[OMP_LIST_LINK])
-    gfc_warning_now (0, "OMP DECLARE TARGET directive at %L with only "
-			"DEVICE_TYPE clause is ignored", &old_loc);
+    gfc_warning_now (OPT_Wopenmp,
+		     "OMP DECLARE TARGET directive at %L with only "
+		     "DEVICE_TYPE clause is ignored", &old_loc);
 
   gfc_buffer_error (true);
 
@@ -7030,7 +7032,8 @@ resolve_positive_int_expr (gfc_expr *expr, const char *clause)
   if (expr->expr_type == EXPR_CONSTANT
       && expr->ts.type == BT_INTEGER
       && mpz_sgn (expr->value.integer) <= 0)
-    gfc_warning (0, "INTEGER expression of %s clause at %L must be positive",
+    gfc_warning ((flag_openmp || flag_openmp_simd) ? OPT_Wopenmp : 0,
+		 "INTEGER expression of %s clause at %L must be positive",
 		 clause, &expr->where);
 }
 
@@ -7041,8 +7044,9 @@ resolve_nonnegative_int_expr (gfc_expr *expr, const char *clause)
   if (expr->expr_type == EXPR_CONSTANT
       && expr->ts.type == BT_INTEGER
       && mpz_sgn (expr->value.integer) < 0)
-    gfc_warning (0, "INTEGER expression of %s clause at %L must be "
-		 "non-negative", clause, &expr->where);
+    gfc_warning ((flag_openmp || flag_openmp_simd) ? OPT_Wopenmp : 0,
+		 "INTEGER expression of %s clause at %L must be non-negative",
+		 clause, &expr->where);
 }
 
 /* Emits error when symbol is pointer, cray pointer or cray pointee
@@ -7605,8 +7609,8 @@ resolve_omp_clauses (gfc_code *code, gfc_omp_clauses *omp_clauses,
       else if (expr->expr_type == EXPR_CONSTANT
 	       && expr->ts.type == BT_INTEGER
 	       && mpz_sgn (expr->value.integer) <= 0)
-	gfc_warning (0, "INTEGER expression of SCHEDULE clause's chunk_size "
-		     "at %L must be positive", &expr->where);
+	gfc_warning (OPT_Wopenmp, "INTEGER expression of SCHEDULE clause's "
+		     "chunk_size at %L must be positive", &expr->where);
     }
   if (omp_clauses->sched_kind != OMP_SCHED_NONE
       && omp_clauses->sched_nonmonotonic)
@@ -7916,8 +7920,8 @@ resolve_omp_clauses (gfc_code *code, gfc_omp_clauses *omp_clauses,
 	    }
 	  if (n->sym->mark == 1)
 	    {
-	      gfc_warning (0, "%qs appears more than once in %<allocate%> "
-			   "at %L" , n->sym->name, &n->where);
+	      gfc_warning (OPT_Wopenmp, "%qs appears more than once in "
+			   "%<allocate%> at %L" , n->sym->name, &n->where);
 	      /* We have already seen this variable so it is a duplicate.
 		 Remove it.  */
 	      if (prev != NULL && prev->next == n)
@@ -8915,8 +8919,8 @@ resolve_omp_clauses (gfc_code *code, gfc_omp_clauses *omp_clauses,
       && omp_clauses->num_teams_upper->expr_type == EXPR_CONSTANT
       && mpz_cmp (omp_clauses->num_teams_lower->value.integer,
 		  omp_clauses->num_teams_upper->value.integer) > 0)
-    gfc_warning (0, "NUM_TEAMS lower bound at %L larger than upper bound at %L",
-		 &omp_clauses->num_teams_lower->where,
+    gfc_warning (OPT_Wopenmp, "NUM_TEAMS lower bound at %L larger than upper "
+		 "bound at %L", &omp_clauses->num_teams_lower->where,
 		 &omp_clauses->num_teams_upper->where);
   if (omp_clauses->device)
     resolve_scalar_int_expr (omp_clauses->device, "DEVICE");
@@ -9753,13 +9757,15 @@ gfc_resolve_omp_do_blocks (gfc_code *code, gfc_namespace *ns)
 	      else
 		{
 		  if (block->op == EXEC_OMP_SCAN)
-		    gfc_warning (0, "!$OMP SCAN at %L with zero executable "
+		    gfc_warning (OPT_Wopenmp,
+				 "!$OMP SCAN at %L with zero executable "
 				 "statements in preceding structured block "
 				 "sequence", &block->loc);
 		  if ((block->op == EXEC_OMP_SCAN && !block->next)
 		      || (block->next && block->next->op == EXEC_OMP_SCAN
 			  && !block->next->next))
-		    gfc_warning (0, "!$OMP SCAN at %L with zero executable "
+		    gfc_warning (OPT_Wopenmp,
+				 "!$OMP SCAN at %L with zero executable "
 				 "statements in succeeding structured block "
 				 "sequence", block->op == EXEC_OMP_SCAN
 				 ? &block->loc : &block->next->loc);
diff --git a/gcc/gimplify.cc b/gcc/gimplify.cc
index d52d71b..02f85e7 100644
--- a/gcc/gimplify.cc
+++ b/gcc/gimplify.cc
@@ -14382,7 +14382,7 @@ gimplify_omp_for (tree *expr_p, gimple_seq *pre_p)
 					       OMP_CLAUSE_LASTPRIVATE))
 		  if (OMP_CLAUSE_DECL (c3) == decl)
 		    {
-		      warning_at (OMP_CLAUSE_LOCATION (c3), 0,
+		      warning_at (OMP_CLAUSE_LOCATION (c3), OPT_Wopenmp,
 				  "conditional %<lastprivate%> on loop "
 				  "iterator %qD ignored", decl);
 		      OMP_CLAUSE_LASTPRIVATE_CONDITIONAL (c3) = 0;
@@ -14490,7 +14490,7 @@ gimplify_omp_for (tree *expr_p, gimple_seq *pre_p)
 					   OMP_CLAUSE_LASTPRIVATE))
 	      if (OMP_CLAUSE_DECL (c3) == decl)
 		{
-		  warning_at (OMP_CLAUSE_LOCATION (c3), 0,
+		  warning_at (OMP_CLAUSE_LOCATION (c3), OPT_Wopenmp,
 			      "conditional %<lastprivate%> on loop "
 			      "iterator %qD ignored", decl);
 		  OMP_CLAUSE_LASTPRIVATE_CONDITIONAL (c3) = 0;
diff --git a/gcc/omp-expand.cc b/gcc/omp-expand.cc
index 5c6a7f2..8281ec6 100644
--- a/gcc/omp-expand.cc
+++ b/gcc/omp-expand.cc
@@ -3416,8 +3416,9 @@ expand_omp_ordered_sink (gimple_stmt_iterator *gsi, struct omp_for_data *fd,
 	      forward = tree_int_cst_sgn (step) != -1;
 	    }
 	  if (forward ^ OMP_CLAUSE_DOACROSS_SINK_NEGATIVE (deps))
-	    warning_at (loc, 0, "%qs clause with %<sink%> modifier "
-				"waiting for lexically later iteration",
+	    warning_at (loc, OPT_Wopenmp,
+			"%qs clause with %<sink%> modifier "
+			"waiting for lexically later iteration",
 			OMP_CLAUSE_DOACROSS_DEPEND (c)
 			? "depend" : "doacross");
 	  break;
@@ -3555,9 +3556,9 @@ expand_omp_ordered_sink (gimple_stmt_iterator *gsi, struct omp_for_data *fd,
 			       build_int_cst (itype, 0));
 	  if (integer_zerop (t) && !warned_step)
 	    {
-	      warning_at (loc, 0, "%qs clause with %<sink%> modifier "
-				  "refers to iteration never in the iteration "
-				  "space",
+	      warning_at (loc, OPT_Wopenmp,
+			  "%qs clause with %<sink%> modifier refers to "
+			  "iteration never in the iteration space",
 			  OMP_CLAUSE_DOACROSS_DEPEND (c)
 			  ? "depend" : "doacross");
 	      warned_step = true;
diff --git a/gcc/omp-general.cc b/gcc/omp-general.cc
index b88d593..8241574 100644
--- a/gcc/omp-general.cc
+++ b/gcc/omp-general.cc
@@ -1201,12 +1201,12 @@ omp_check_context_selector (location_t loc, tree ctx)
 			  return error_mark_node;
 			}
 		      else if (TREE_PURPOSE (t2))
-			warning_at (loc, 0,
+			warning_at (loc, OPT_Wopenmp,
 				    "unknown property %qs of %qs selector",
 				    IDENTIFIER_POINTER (TREE_PURPOSE (t2)),
 				    props[i].selector);
 		      else
-			warning_at (loc, 0,
+			warning_at (loc, OPT_Wopenmp,
 				    "unknown property %qE of %qs selector",
 				    TREE_VALUE (t2), props[i].selector);
 		      break;
diff --git a/gcc/omp-low.cc b/gcc/omp-low.cc
index 161bcfe..dd802ca 100644
--- a/gcc/omp-low.cc
+++ b/gcc/omp-low.cc
@@ -2844,12 +2844,13 @@ scan_omp_for (gomp_for *stmt, omp_context *outer_ctx)
 	      tree_code outer_op = OMP_CLAUSE_REDUCTION_CODE (outer_clause);
 	      if (outer_var == local_var && outer_op != local_op)
 		{
-		  warning_at (OMP_CLAUSE_LOCATION (local_clause), 0,
-			      "conflicting reduction operations for %qE",
-			      local_var);
-		  inform (OMP_CLAUSE_LOCATION (outer_clause),
-			  "location of the previous reduction for %qE",
-			  outer_var);
+		  if (warning_at (OMP_CLAUSE_LOCATION (local_clause),
+				  OPT_Wopenmp, "conflicting reduction "
+					       "operations for %qE",
+				  local_var))
+		    inform (OMP_CLAUSE_LOCATION (outer_clause),
+			    "location of the previous reduction for %qE",
+			    outer_var);
 		}
 	      if (outer_var == local_var)
 		{
@@ -2880,7 +2881,7 @@ scan_omp_for (gomp_for *stmt, omp_context *outer_ctx)
 			}
 		    }
 		  if (!found)
-		    warning_at (gimple_location (curr_loop->stmt), 0,
+		    warning_at (gimple_location (curr_loop->stmt), OPT_Wopenmp,
 				"nested loop in reduction needs "
 				"reduction clause for %qE",
 				local_var);
@@ -3427,12 +3428,12 @@ check_omp_nesting_restrictions (gimple *stmt, omp_context *ctx)
 		  ctx->cancellable = true;
 		  if (omp_find_clause (gimple_omp_for_clauses (ctx->stmt),
 				       OMP_CLAUSE_NOWAIT))
-		    warning_at (gimple_location (stmt), 0,
+		    warning_at (gimple_location (stmt), OPT_Wopenmp,
 				"%<cancel for%> inside "
 				"%<nowait%> for construct");
 		  if (omp_find_clause (gimple_omp_for_clauses (ctx->stmt),
 				       OMP_CLAUSE_ORDERED))
-		    warning_at (gimple_location (stmt), 0,
+		    warning_at (gimple_location (stmt), OPT_Wopenmp,
 				"%<cancel for%> inside "
 				"%<ordered%> for construct");
 		}
@@ -3452,7 +3453,7 @@ check_omp_nesting_restrictions (gimple *stmt, omp_context *ctx)
 		      if (omp_find_clause (gimple_omp_sections_clauses
 								(ctx->stmt),
 					   OMP_CLAUSE_NOWAIT))
-			warning_at (gimple_location (stmt), 0,
+			warning_at (gimple_location (stmt), OPT_Wopenmp,
 				    "%<cancel sections%> inside "
 				    "%<nowait%> sections construct");
 		    }
@@ -3465,7 +3466,7 @@ check_omp_nesting_restrictions (gimple *stmt, omp_context *ctx)
 		      if (omp_find_clause (gimple_omp_sections_clauses
 							(ctx->outer->stmt),
 					   OMP_CLAUSE_NOWAIT))
-			warning_at (gimple_location (stmt), 0,
+			warning_at (gimple_location (stmt), OPT_Wopenmp,
 				    "%<cancel sections%> inside "
 				    "%<nowait%> sections construct");
 		    }
@@ -3928,7 +3929,7 @@ check_omp_nesting_restrictions (gimple *stmt, omp_context *ctx)
 		      if (c && OMP_CLAUSE_DEVICE_ANCESTOR (c))
 			break;
 		    }
-		  warning_at (gimple_location (stmt), 0,
+		  warning_at (gimple_location (stmt), OPT_Wopenmp,
 			      "%qs construct inside of %qs region",
 			      stmt_name, ctx_stmt_name);
 		}
@@ -9783,8 +9784,8 @@ lower_omp_ordered_clauses (gimple_stmt_iterator *gsi_p, gomp_ordered *ord_stmt,
 				  wi::abs (wi::to_wide (fd.loops[i].step)),
 				  UNSIGNED))
 	    {
-	      warning_at (OMP_CLAUSE_LOCATION (c), 0,
-			  "ignoring sink clause with offset that is not "
+	      warning_at (OMP_CLAUSE_LOCATION (c), OPT_Wopenmp,
+			  "ignoring %<sink%> clause with offset that is not "
 			  "a multiple of the loop step");
 	      remove = true;
 	      goto next_ordered_clause;
diff --git a/gcc/omp-simd-clone.cc b/gcc/omp-simd-clone.cc
index 57b0793..3fbe428 100644
--- a/gcc/omp-simd-clone.cc
+++ b/gcc/omp-simd-clone.cc
@@ -387,13 +387,13 @@ simd_clone_clauses_extract (struct cgraph_node *node, tree clauses,
 		  step = fold_convert (ssizetype, step);
 		if (!tree_fits_shwi_p (step))
 		  {
-		    warning_at (OMP_CLAUSE_LOCATION (t), 0,
+		    warning_at (OMP_CLAUSE_LOCATION (t), OPT_Wopenmp,
 				"ignoring large linear step");
 		    return NULL;
 		  }
 		else if (integer_zerop (step))
 		  {
-		    warning_at (OMP_CLAUSE_LOCATION (t), 0,
+		    warning_at (OMP_CLAUSE_LOCATION (t), OPT_Wopenmp,
 				"ignoring zero linear step");
 		    return NULL;
 		  }
@@ -455,7 +455,7 @@ simd_clone_clauses_extract (struct cgraph_node *node, tree clauses,
  out:
   if (TYPE_ATOMIC (TREE_TYPE (TREE_TYPE (node->decl))))
     {
-      warning_at (DECL_SOURCE_LOCATION (node->decl), 0,
+      warning_at (DECL_SOURCE_LOCATION (node->decl), OPT_Wopenmp,
 		  "ignoring %<#pragma omp declare simd%> on function "
 		  "with %<_Atomic%> qualified return type");
       return NULL;
@@ -465,7 +465,7 @@ simd_clone_clauses_extract (struct cgraph_node *node, tree clauses,
     if (TYPE_ATOMIC (args[argno])
 	&& clone_info->args[argno].arg_type != SIMD_CLONE_ARG_TYPE_UNIFORM)
       {
-	warning_at (DECL_SOURCE_LOCATION (node->decl), 0,
+	warning_at (DECL_SOURCE_LOCATION (node->decl), OPT_Wopenmp,
 		    "ignoring %<#pragma omp declare simd%> on function "
 		    "with %<_Atomic%> qualified non-%<uniform%> argument");
 	args.release ();