RE: [PATCH 1/2][frontend] Add novector C++ pragma

[Tamar Christina <Tamar.Christina@arm.com>]

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> > +
> > +	cp_token *tok = pragma_tok;
> > +
> > +	do
> >   	  {
> > -	    tok = cp_lexer_consume_token (parser->lexer);
> > -	    ivdep = cp_parser_pragma_ivdep (parser, tok);
> > -	    tok = cp_lexer_peek_token (the_parser->lexer);
> > +	    switch (cp_parser_pragma_kind (tok))
> > +	      {
> > +		case PRAGMA_IVDEP:
> > +		  {
> > +		    if (tok != pragma_tok)
> > +		      tok = cp_lexer_consume_token (parser->lexer);
> > +		    ivdep = cp_parser_pragma_ivdep (parser, tok);
> > +		    tok = cp_lexer_peek_token (the_parser->lexer);
> > +		    break;
> > +		  }
> > +		case PRAGMA_UNROLL:
> > +		  {
> > +		    if (tok != pragma_tok)
> > +		      tok = cp_lexer_consume_token (parser->lexer);
> > +		    unroll = cp_parser_pragma_unroll (parser, tok);
> > +		    tok = cp_lexer_peek_token (the_parser->lexer);
> > +		    break;
> > +		  }
> > +		case PRAGMA_NOVECTOR:
> > +		  {
> > +		    if (tok != pragma_tok)
> > +		      tok = cp_lexer_consume_token (parser->lexer);
> > +		    novector = cp_parser_pragma_novector (parser, tok);
> > +		    tok = cp_lexer_peek_token (the_parser->lexer);
> > +		    break;
> > +		  }
> > +		default:
> > +		  gcc_unreachable ();
> 
> This unreachable seems to assert that if a pragma follows one of these
> pragmas, it must be another one of these pragmas?  That seems wrong;
> instead of hitting gcc_unreachable() in that case we should fall through to the
> diagnostic below.
> 

Ah, good should. Since it has to exit two levels I had to introduce a bool
for controlling the loop iterations.  New patch below.

Bootstrapped Regtested on aarch64-none-linux-gnu and no issues.

Ok for master?

Thanks,
Tamar

gcc/cp/ChangeLog:

	* cp-tree.h (RANGE_FOR_NOVECTOR): New.
	(cp_convert_range_for, finish_while_stmt_cond, finish_do_stmt,
	finish_for_cond): Add novector param.
	* init.cc (build_vec_init): Default novector to false.
	* method.cc (build_comparison_op): Likewise.
	* parser.cc (cp_parser_statement): Likewise.
	(cp_parser_for, cp_parser_c_for, cp_parser_range_for,
	cp_convert_range_for, cp_parser_iteration_statement,
	cp_parser_omp_for_loop, cp_parser_pragma): Support novector.
	(cp_parser_pragma_novector): New.
	* pt.cc (tsubst_expr): Likewise.
	* semantics.cc (finish_while_stmt_cond, finish_do_stmt,
	finish_for_cond): Likewise.

gcc/ChangeLog:

	* doc/extend.texi: Document it.

gcc/testsuite/ChangeLog:

	* g++.dg/vect/vect.exp (support vect- prefix).
	* g++.dg/vect/vect-novector-pragma.cc: New test.

--- inline copy of patch ---

diff --git a/gcc/cp/cp-tree.h b/gcc/cp/cp-tree.h
index 8398223311194837441107cb335d497ff5f5ec1c..bece7bff1f01a23cfc94386fd3295a0be8c462fe 100644
--- a/gcc/cp/cp-tree.h
+++ b/gcc/cp/cp-tree.h
@@ -5377,6 +5377,7 @@ get_vec_init_expr (tree t)
 #define RANGE_FOR_UNROLL(NODE)	TREE_OPERAND (RANGE_FOR_STMT_CHECK (NODE), 4)
 #define RANGE_FOR_INIT_STMT(NODE) TREE_OPERAND (RANGE_FOR_STMT_CHECK (NODE), 5)
 #define RANGE_FOR_IVDEP(NODE)	TREE_LANG_FLAG_6 (RANGE_FOR_STMT_CHECK (NODE))
+#define RANGE_FOR_NOVECTOR(NODE) TREE_LANG_FLAG_5 (RANGE_FOR_STMT_CHECK (NODE))
 
 /* STMT_EXPR accessor.  */
 #define STMT_EXPR_STMT(NODE)	TREE_OPERAND (STMT_EXPR_CHECK (NODE), 0)
@@ -7286,7 +7287,7 @@ extern bool maybe_clone_body			(tree);
 
 /* In parser.cc */
 extern tree cp_convert_range_for (tree, tree, tree, tree, unsigned int, bool,
-				  unsigned short);
+				  unsigned short, bool);
 extern void cp_convert_omp_range_for (tree &, vec<tree, va_gc> *, tree &,
 				      tree &, tree &, tree &, tree &, tree &);
 extern void cp_finish_omp_range_for (tree, tree);
@@ -7609,16 +7610,19 @@ extern void begin_else_clause			(tree);
 extern void finish_else_clause			(tree);
 extern void finish_if_stmt			(tree);
 extern tree begin_while_stmt			(void);
-extern void finish_while_stmt_cond	(tree, tree, bool, unsigned short);
+extern void finish_while_stmt_cond	(tree, tree, bool, unsigned short,
+					 bool);
 extern void finish_while_stmt			(tree);
 extern tree begin_do_stmt			(void);
 extern void finish_do_body			(tree);
-extern void finish_do_stmt		(tree, tree, bool, unsigned short);
+extern void finish_do_stmt		(tree, tree, bool, unsigned short,
+					 bool);
 extern tree finish_return_stmt			(tree);
 extern tree begin_for_scope			(tree *);
 extern tree begin_for_stmt			(tree, tree);
 extern void finish_init_stmt			(tree);
-extern void finish_for_cond		(tree, tree, bool, unsigned short);
+extern void finish_for_cond		(tree, tree, bool, unsigned short,
+					 bool);
 extern void finish_for_expr			(tree, tree);
 extern void finish_for_stmt			(tree);
 extern tree begin_range_for_stmt		(tree, tree);
diff --git a/gcc/cp/init.cc b/gcc/cp/init.cc
index af6e30f511e142c7a594e742d128b2bf0aa8fb8d..5b735b27e6f5bc6b439ae64665902f4f1ca76f95 100644
--- a/gcc/cp/init.cc
+++ b/gcc/cp/init.cc
@@ -4846,7 +4846,7 @@ build_vec_init (tree base, tree maxindex, tree init,
       finish_init_stmt (for_stmt);
       finish_for_cond (build2 (GT_EXPR, boolean_type_node, iterator,
 			       build_int_cst (TREE_TYPE (iterator), -1)),
-		       for_stmt, false, 0);
+		       for_stmt, false, 0, false);
       /* We used to pass this decrement to finish_for_expr; now we add it to
 	 elt_init below so it's part of the same full-expression as the
 	 initialization, and thus happens before any potentially throwing
diff --git a/gcc/cp/method.cc b/gcc/cp/method.cc
index 91cf943f11089c0e6bcbe8377daa4e016f956d56..fce49c796199c2c65cd70684e2942fea1b6b2ebd 100644
--- a/gcc/cp/method.cc
+++ b/gcc/cp/method.cc
@@ -1645,7 +1645,8 @@ build_comparison_op (tree fndecl, bool defining, tsubst_flags_t complain)
 		      add_stmt (idx);
 		      finish_init_stmt (for_stmt);
 		      finish_for_cond (build2 (LE_EXPR, boolean_type_node, idx,
-					       maxval), for_stmt, false, 0);
+					       maxval), for_stmt, false, 0,
+					       false);
 		      finish_for_expr (cp_build_unary_op (PREINCREMENT_EXPR,
 							  TARGET_EXPR_SLOT (idx),
 							  false, complain),
diff --git a/gcc/cp/parser.cc b/gcc/cp/parser.cc
index dd3665c8ccf48a8a0b1ba2c06400fe50999ea240..092f991d7a1b6aab8482d50848fb9fb96c377509 100644
--- a/gcc/cp/parser.cc
+++ b/gcc/cp/parser.cc
@@ -2324,15 +2324,15 @@ static tree cp_parser_selection_statement
 static tree cp_parser_condition
   (cp_parser *);
 static tree cp_parser_iteration_statement
-  (cp_parser *, bool *, bool, unsigned short);
+  (cp_parser *, bool *, bool, unsigned short, bool);
 static bool cp_parser_init_statement
   (cp_parser *, tree *decl);
 static tree cp_parser_for
-  (cp_parser *, bool, unsigned short);
+  (cp_parser *, bool, unsigned short, bool);
 static tree cp_parser_c_for
-  (cp_parser *, tree, tree, bool, unsigned short);
+  (cp_parser *, tree, tree, bool, unsigned short, bool);
 static tree cp_parser_range_for
-  (cp_parser *, tree, tree, tree, bool, unsigned short, bool);
+  (cp_parser *, tree, tree, tree, bool, unsigned short, bool, bool);
 static void do_range_for_auto_deduction
   (tree, tree, tree, unsigned int);
 static tree cp_parser_perform_range_for_lookup
@@ -12414,7 +12414,8 @@ cp_parser_statement (cp_parser* parser, tree in_statement_expr,
 	case RID_DO:
 	case RID_FOR:
 	  std_attrs = process_stmt_hotness_attribute (std_attrs, attrs_loc);
-	  statement = cp_parser_iteration_statement (parser, if_p, false, 0);
+	  statement = cp_parser_iteration_statement (parser, if_p, false, 0,
+						     false);
 	  break;
 
 	case RID_BREAK:
@@ -13594,7 +13595,8 @@ cp_parser_condition (cp_parser* parser)
    not included. */
 
 static tree
-cp_parser_for (cp_parser *parser, bool ivdep, unsigned short unroll)
+cp_parser_for (cp_parser *parser, bool ivdep, unsigned short unroll,
+	       bool novector)
 {
   tree init, scope, decl;
   bool is_range_for;
@@ -13624,14 +13626,14 @@ cp_parser_for (cp_parser *parser, bool ivdep, unsigned short unroll)
 
   if (is_range_for)
     return cp_parser_range_for (parser, scope, init, decl, ivdep, unroll,
-				false);
+				novector, false);
   else
-    return cp_parser_c_for (parser, scope, init, ivdep, unroll);
+    return cp_parser_c_for (parser, scope, init, ivdep, unroll, novector);
 }
 
 static tree
 cp_parser_c_for (cp_parser *parser, tree scope, tree init, bool ivdep,
-		 unsigned short unroll)
+		 unsigned short unroll, bool novector)
 {
   /* Normal for loop */
   tree condition = NULL_TREE;
@@ -13658,7 +13660,7 @@ cp_parser_c_for (cp_parser *parser, tree scope, tree init, bool ivdep,
 		       "%<GCC unroll%> pragma");
       condition = error_mark_node;
     }
-  finish_for_cond (condition, stmt, ivdep, unroll);
+  finish_for_cond (condition, stmt, ivdep, unroll, novector);
   /* Look for the `;'.  */
   cp_parser_require (parser, CPP_SEMICOLON, RT_SEMICOLON);
 
@@ -13682,7 +13684,8 @@ cp_parser_c_for (cp_parser *parser, tree scope, tree init, bool ivdep,
 
 static tree
 cp_parser_range_for (cp_parser *parser, tree scope, tree init, tree range_decl,
-		     bool ivdep, unsigned short unroll, bool is_omp)
+		     bool ivdep, unsigned short unroll, bool novector,
+		     bool is_omp)
 {
   tree stmt, range_expr;
   auto_vec <cxx_binding *, 16> bindings;
@@ -13758,6 +13761,8 @@ cp_parser_range_for (cp_parser *parser, tree scope, tree init, tree range_decl,
 	RANGE_FOR_IVDEP (stmt) = 1;
       if (unroll)
 	RANGE_FOR_UNROLL (stmt) = build_int_cst (integer_type_node, unroll);
+      if (novector)
+	RANGE_FOR_NOVECTOR (stmt) = 1;
       finish_range_for_decl (stmt, range_decl, range_expr);
       if (!type_dependent_expression_p (range_expr)
 	  /* do_auto_deduction doesn't mess with template init-lists.  */
@@ -13770,7 +13775,7 @@ cp_parser_range_for (cp_parser *parser, tree scope, tree init, tree range_decl,
       stmt = begin_for_stmt (scope, init);
       stmt = cp_convert_range_for (stmt, range_decl, range_expr,
 				   decomp_first_name, decomp_cnt, ivdep,
-				   unroll);
+				   unroll, novector);
     }
   return stmt;
 }
@@ -13948,7 +13953,7 @@ warn_for_range_copy (tree decl, tree expr)
 tree
 cp_convert_range_for (tree statement, tree range_decl, tree range_expr,
 		      tree decomp_first_name, unsigned int decomp_cnt,
-		      bool ivdep, unsigned short unroll)
+		      bool ivdep, unsigned short unroll, bool novector)
 {
   tree begin, end;
   tree iter_type, begin_expr, end_expr;
@@ -14008,7 +14013,7 @@ cp_convert_range_for (tree statement, tree range_decl, tree range_expr,
 				 begin, ERROR_MARK,
 				 end, ERROR_MARK,
 				 NULL_TREE, NULL, tf_warning_or_error);
-  finish_for_cond (condition, statement, ivdep, unroll);
+  finish_for_cond (condition, statement, ivdep, unroll, novector);
 
   /* The new increment expression.  */
   expression = finish_unary_op_expr (input_location,
@@ -14175,7 +14180,7 @@ cp_parser_range_for_member_function (tree range, tree identifier)
 
 static tree
 cp_parser_iteration_statement (cp_parser* parser, bool *if_p, bool ivdep,
-			       unsigned short unroll)
+			       unsigned short unroll, bool novector)
 {
   cp_token *token;
   enum rid keyword;
@@ -14209,7 +14214,7 @@ cp_parser_iteration_statement (cp_parser* parser, bool *if_p, bool ivdep,
 	parens.require_open (parser);
 	/* Parse the condition.  */
 	condition = cp_parser_condition (parser);
-	finish_while_stmt_cond (condition, statement, ivdep, unroll);
+	finish_while_stmt_cond (condition, statement, ivdep, unroll, novector);
 	/* Look for the `)'.  */
 	parens.require_close (parser);
 	/* Parse the dependent statement.  */
@@ -14244,7 +14249,7 @@ cp_parser_iteration_statement (cp_parser* parser, bool *if_p, bool ivdep,
 	/* Parse the expression.  */
 	expression = cp_parser_expression (parser);
 	/* We're done with the do-statement.  */
-	finish_do_stmt (expression, statement, ivdep, unroll);
+	finish_do_stmt (expression, statement, ivdep, unroll, novector);
 	/* Look for the `)'.  */
 	parens.require_close (parser);
 	/* Look for the `;'.  */
@@ -14258,7 +14263,7 @@ cp_parser_iteration_statement (cp_parser* parser, bool *if_p, bool ivdep,
 	matching_parens parens;
 	parens.require_open (parser);
 
-	statement = cp_parser_for (parser, ivdep, unroll);
+	statement = cp_parser_for (parser, ivdep, unroll, novector);
 
 	/* Look for the `)'.  */
 	parens.require_close (parser);
@@ -43815,7 +43820,7 @@ cp_parser_omp_for_loop (cp_parser *parser, enum tree_code code, tree clauses,
 	      cp_parser_require (parser, CPP_COLON, RT_COLON);
 
 	      init = cp_parser_range_for (parser, NULL_TREE, NULL_TREE, decl,
-					  false, 0, true);
+					  false, 0, false, true);
 
 	      cp_convert_omp_range_for (this_pre_body, for_block, decl,
 					orig_decl, init, orig_init,
@@ -49300,6 +49305,15 @@ cp_parser_pragma_unroll (cp_parser *parser, cp_token *pragma_tok)
   return unroll;
 }
 
+/* Parse a pragma GCC novector.  */
+
+static bool
+cp_parser_pragma_novector (cp_parser *parser, cp_token *pragma_tok)
+{
+  cp_parser_skip_to_pragma_eol (parser, pragma_tok);
+  return true;
+}
+
 /* Normal parsing of a pragma token.  Here we can (and must) use the
    regular lexer.  */
 
@@ -49605,58 +49619,73 @@ cp_parser_pragma (cp_parser *parser, enum pragma_context context, bool *if_p)
       break;
 
     case PRAGMA_IVDEP:
+    case PRAGMA_UNROLL:
+    case PRAGMA_NOVECTOR:
       {
-	if (context == pragma_external)
+	bool ivdep;
+	unsigned short unroll = 0;
+	bool novector = false;
+	const char *pragma_str;
+
+	switch (id)
 	  {
-	    error_at (pragma_tok->location,
-		      "%<#pragma GCC ivdep%> must be inside a function");
+	  case PRAGMA_IVDEP:
+	    pragma_str = "ivdep";
 	    break;
-	  }
-	const bool ivdep = cp_parser_pragma_ivdep (parser, pragma_tok);
-	unsigned short unroll;
-	cp_token *tok = cp_lexer_peek_token (the_parser->lexer);
-	if (tok->type == CPP_PRAGMA
-	    && cp_parser_pragma_kind (tok) == PRAGMA_UNROLL)
-	  {
-	    tok = cp_lexer_consume_token (parser->lexer);
-	    unroll = cp_parser_pragma_unroll (parser, tok);
-	    tok = cp_lexer_peek_token (the_parser->lexer);
-	  }
-	else
-	  unroll = 0;
-	if (tok->type != CPP_KEYWORD
-	    || (tok->keyword != RID_FOR
-		&& tok->keyword != RID_WHILE
-		&& tok->keyword != RID_DO))
-	  {
-	    cp_parser_error (parser, "for, while or do statement expected");
-	    return false;
-	  }
-	cp_parser_iteration_statement (parser, if_p, ivdep, unroll);
-	return true;
-      }
+	  case PRAGMA_UNROLL:
+	    pragma_str = "unroll";
+	    break;
+	  case PRAGMA_NOVECTOR:
+	    pragma_str = "novector";
+	    break;
+	  default:
+	    gcc_unreachable ();
+	}
 
-    case PRAGMA_UNROLL:
-      {
 	if (context == pragma_external)
 	  {
 	    error_at (pragma_tok->location,
-		      "%<#pragma GCC unroll%> must be inside a function");
+		      "%<#pragma GCC %s%> must be inside a function",
+		      pragma_str);
 	    break;
 	  }
-	const unsigned short unroll
-	  = cp_parser_pragma_unroll (parser, pragma_tok);
-	bool ivdep;
-	cp_token *tok = cp_lexer_peek_token (the_parser->lexer);
-	if (tok->type == CPP_PRAGMA
-	    && cp_parser_pragma_kind (tok) == PRAGMA_IVDEP)
+
+	cp_token *tok = pragma_tok;
+	bool has_more = true;
+	do
 	  {
-	    tok = cp_lexer_consume_token (parser->lexer);
-	    ivdep = cp_parser_pragma_ivdep (parser, tok);
+	    switch (cp_parser_pragma_kind (tok))
+	      {
+		case PRAGMA_IVDEP:
+		  {
+		    if (tok != pragma_tok)
+		      tok = cp_lexer_consume_token (parser->lexer);
+		    ivdep = cp_parser_pragma_ivdep (parser, tok);
+		    break;
+		  }
+		case PRAGMA_UNROLL:
+		  {
+		    if (tok != pragma_tok)
+		      tok = cp_lexer_consume_token (parser->lexer);
+		    unroll = cp_parser_pragma_unroll (parser, tok);
+		    break;
+		  }
+		case PRAGMA_NOVECTOR:
+		  {
+		    if (tok != pragma_tok)
+		      tok = cp_lexer_consume_token (parser->lexer);
+		    novector = cp_parser_pragma_novector (parser, tok);
+		    break;
+		  }
+		default:
+		  has_more = false;
+		  break;
+	      }
 	    tok = cp_lexer_peek_token (the_parser->lexer);
+	    has_more = has_more && tok->type == CPP_PRAGMA;
 	  }
-	else
-	  ivdep = false;
+	while (has_more);
+
 	if (tok->type != CPP_KEYWORD
 	    || (tok->keyword != RID_FOR
 		&& tok->keyword != RID_WHILE
@@ -49665,7 +49694,7 @@ cp_parser_pragma (cp_parser *parser, enum pragma_context context, bool *if_p)
 	    cp_parser_error (parser, "for, while or do statement expected");
 	    return false;
 	  }
-	cp_parser_iteration_statement (parser, if_p, ivdep, unroll);
+	cp_parser_iteration_statement (parser, if_p, ivdep, unroll, novector);
 	return true;
       }
 
diff --git a/gcc/cp/pt.cc b/gcc/cp/pt.cc
index 2345a18becc1160b9d12f3d88cccb66c8917373c..7b0d01a90e3c4012ec603ebe04cbbb31a7dd1570 100644
--- a/gcc/cp/pt.cc
+++ b/gcc/cp/pt.cc
@@ -19036,7 +19036,7 @@ tsubst_expr (tree t, tree args, tsubst_flags_t complain, tree in_decl)
       RECUR (FOR_INIT_STMT (t));
       finish_init_stmt (stmt);
       tmp = RECUR (FOR_COND (t));
-      finish_for_cond (tmp, stmt, false, 0);
+      finish_for_cond (tmp, stmt, false, 0, false);
       tmp = RECUR (FOR_EXPR (t));
       finish_for_expr (tmp, stmt);
       {
@@ -19073,6 +19073,7 @@ tsubst_expr (tree t, tree args, tsubst_flags_t complain, tree in_decl)
 	  {
 	    RANGE_FOR_IVDEP (stmt) = RANGE_FOR_IVDEP (t);
 	    RANGE_FOR_UNROLL (stmt) = RANGE_FOR_UNROLL (t);
+	    RANGE_FOR_NOVECTOR (stmt) = RANGE_FOR_NOVECTOR (t);
 	    finish_range_for_decl (stmt, decl, expr);
 	    if (decomp_first && decl != error_mark_node)
 	      cp_finish_decomp (decl, decomp_first, decomp_cnt);
@@ -19083,7 +19084,8 @@ tsubst_expr (tree t, tree args, tsubst_flags_t complain, tree in_decl)
 				     ? tree_to_uhwi (RANGE_FOR_UNROLL (t)) : 0);
 	    stmt = cp_convert_range_for (stmt, decl, expr,
 					 decomp_first, decomp_cnt,
-					 RANGE_FOR_IVDEP (t), unroll);
+					 RANGE_FOR_IVDEP (t), unroll,
+					 RANGE_FOR_NOVECTOR (t));
 	  }
 
 	bool prev = note_iteration_stmt_body_start ();
@@ -19096,7 +19098,7 @@ tsubst_expr (tree t, tree args, tsubst_flags_t complain, tree in_decl)
     case WHILE_STMT:
       stmt = begin_while_stmt ();
       tmp = RECUR (WHILE_COND (t));
-      finish_while_stmt_cond (tmp, stmt, false, 0);
+      finish_while_stmt_cond (tmp, stmt, false, 0, false);
       {
 	bool prev = note_iteration_stmt_body_start ();
 	RECUR (WHILE_BODY (t));
@@ -19114,7 +19116,7 @@ tsubst_expr (tree t, tree args, tsubst_flags_t complain, tree in_decl)
       }
       finish_do_body (stmt);
       tmp = RECUR (DO_COND (t));
-      finish_do_stmt (tmp, stmt, false, 0);
+      finish_do_stmt (tmp, stmt, false, 0, false);
       break;
 
     case IF_STMT:
diff --git a/gcc/cp/semantics.cc b/gcc/cp/semantics.cc
index 8fb47fd179eb2af2e82bf31d188023e9b9d41de9..b79975109c22ebcfcb060b4f20f32f69f3c3c444 100644
--- a/gcc/cp/semantics.cc
+++ b/gcc/cp/semantics.cc
@@ -1148,7 +1148,7 @@ begin_while_stmt (void)
 
 void
 finish_while_stmt_cond (tree cond, tree while_stmt, bool ivdep,
-			unsigned short unroll)
+			unsigned short unroll, bool novector)
 {
   cond = maybe_convert_cond (cond);
   finish_cond (&WHILE_COND (while_stmt), cond);
@@ -1168,6 +1168,13 @@ finish_while_stmt_cond (tree cond, tree while_stmt, bool ivdep,
 						     annot_expr_unroll_kind),
 				      build_int_cst (integer_type_node,
 						     unroll));
+  if (novector && cond != error_mark_node)
+    WHILE_COND (while_stmt) = build3 (ANNOTATE_EXPR,
+				      TREE_TYPE (WHILE_COND (while_stmt)),
+				      WHILE_COND (while_stmt),
+				      build_int_cst (integer_type_node,
+						     annot_expr_no_vector_kind),
+				      integer_zero_node);
   simplify_loop_decl_cond (&WHILE_COND (while_stmt), WHILE_BODY (while_stmt));
 }
 
@@ -1212,7 +1219,8 @@ finish_do_body (tree do_stmt)
    COND is as indicated.  */
 
 void
-finish_do_stmt (tree cond, tree do_stmt, bool ivdep, unsigned short unroll)
+finish_do_stmt (tree cond, tree do_stmt, bool ivdep, unsigned short unroll,
+		bool novector)
 {
   cond = maybe_convert_cond (cond);
   end_maybe_infinite_loop (cond);
@@ -1229,6 +1237,10 @@ finish_do_stmt (tree cond, tree do_stmt, bool ivdep, unsigned short unroll)
     cond = build3 (ANNOTATE_EXPR, TREE_TYPE (cond), cond,
 		   build_int_cst (integer_type_node, annot_expr_unroll_kind),
 		   build_int_cst (integer_type_node, unroll));
+  if (novector && cond != error_mark_node)
+    cond = build3 (ANNOTATE_EXPR, TREE_TYPE (cond), cond,
+		   build_int_cst (integer_type_node, annot_expr_no_vector_kind),
+		   integer_zero_node);
   DO_COND (do_stmt) = cond;
 }
 
@@ -1325,7 +1337,7 @@ finish_init_stmt (tree for_stmt)
    FOR_STMT.  */
 
 void
-finish_for_cond (tree cond, tree for_stmt, bool ivdep, unsigned short unroll)
+finish_for_cond (tree cond, tree for_stmt, bool ivdep, unsigned short unroll, bool novector)
 {
   cond = maybe_convert_cond (cond);
   finish_cond (&FOR_COND (for_stmt), cond);
@@ -1345,6 +1357,13 @@ finish_for_cond (tree cond, tree for_stmt, bool ivdep, unsigned short unroll)
 						 annot_expr_unroll_kind),
 				  build_int_cst (integer_type_node,
 						 unroll));
+  if (novector && cond != error_mark_node)
+    FOR_COND (for_stmt) = build3 (ANNOTATE_EXPR,
+				  TREE_TYPE (FOR_COND (for_stmt)),
+				  FOR_COND (for_stmt),
+				  build_int_cst (integer_type_node,
+						 annot_expr_no_vector_kind),
+				  integer_zero_node);
   simplify_loop_decl_cond (&FOR_COND (for_stmt), FOR_BODY (for_stmt));
 }
 
diff --git a/gcc/doc/extend.texi b/gcc/doc/extend.texi
index 3040a9bdea65d27f8d20572b4ed37375f5fe949b..baac6643d1abbf33d592e68aca49ac83e3c29188 100644
--- a/gcc/doc/extend.texi
+++ b/gcc/doc/extend.texi
@@ -24349,6 +24349,25 @@ void ignore_vec_dep (int *a, int k, int c, int m)
 @}
 @end smallexample
 
+@cindex pragma GCC novector
+@item #pragma GCC novector
+
+With this pragma, the programmer asserts that the following loop should be
+prevented from executing concurrently with SIMD (single instruction multiple
+data) instructions.
+
+For example, the compiler cannot vectorize the following loop with the pragma:
+
+@smallexample
+void foo (int n, int *a, int *b, int *c)
+@{
+  int i, j;
+#pragma GCC novector
+  for (i = 0; i < n; ++i)
+    a[i] = b[i] + c[i];
+@}
+@end smallexample
+
 @cindex pragma GCC unroll @var{n}
 @item #pragma GCC unroll @var{n}
 
diff --git a/gcc/testsuite/g++.dg/vect/vect-novector-pragma.cc b/gcc/testsuite/g++.dg/vect/vect-novector-pragma.cc
new file mode 100644
index 0000000000000000000000000000000000000000..8c6ff22fcaabaa97516be72b77acbd44df86b1d2
--- /dev/null
+++ b/gcc/testsuite/g++.dg/vect/vect-novector-pragma.cc
@@ -0,0 +1,69 @@
+/* { dg-do compile } */
+/* { dg-require-effective-target vect_int } */
+
+#include <vector>
+
+void f4 (std::vector<int> a, std::vector<int> b, int n)
+{
+    int i = 0;
+#pragma GCC novector
+    while (i < (n & -8))
+      {
+        a[i] += b[i];
+        i++;
+      }
+}
+
+void f5 (std::vector<int> a, std::vector<int> b, int n)
+{
+    int i = 0;
+#pragma GCC novector
+#pragma GCC ivdep
+#pragma GCC unroll 2
+    while (i < (n & -8))
+      {
+        a[i] += b[i];
+        i++;
+      }
+}
+
+void f6 (std::vector<int> a, std::vector<int> b, int n)
+{
+    int i = 0;
+#pragma GCC ivdep
+#pragma GCC novector
+#pragma GCC unroll 2
+    while (i < (n & -8))
+      {
+        a[i] += b[i];
+        i++;
+      }
+}
+
+void f7 (std::vector<int> a, std::vector<int> b, int n)
+{
+    int i = 0;
+#pragma GCC ivdep
+#pragma GCC unroll 2
+#pragma GCC novector
+    while (i < (n & -8))
+      {
+        a[i] += b[i];
+        i++;
+      }
+}
+
+#if __cpp_range_based_for
+void f8 (std::vector<int> a, std::vector<int> b, int n)
+{
+    int i = 0;
+#pragma GCC novector
+    for (int x : b)
+      {
+        a[i] += x;
+        i++;
+      }
+}
+#endif
+
+/* { dg-final { scan-tree-dump-not "LOOP VECTORIZED" "vect" } } */
diff --git a/gcc/testsuite/g++.dg/vect/vect.exp b/gcc/testsuite/g++.dg/vect/vect.exp
index df273233f47a788024bbe61128eaa96b639cb3b8..fc77120a83173c65ad147e8bb7c29ac82f06bb6d 100644
--- a/gcc/testsuite/g++.dg/vect/vect.exp
+++ b/gcc/testsuite/g++.dg/vect/vect.exp
@@ -64,7 +64,7 @@ dg-init
 
 # Main loop.
 et-dg-runtest g++-dg-runtest [lsort [glob -nocomplain \
-	$srcdir/$subdir/{pr,simd}*.{c,cc,S} ]] "" $DEFAULT_VECTCFLAGS
+	$srcdir/$subdir/{pr,simd,vect-}*.{c,cc,S} ]] "" $DEFAULT_VECTCFLAGS
 et-dg-runtest g++-dg-runtest [lsort [glob -nocomplain \
 	$srcdir/$subdir/slp-pr*.{c,cc,S} ]] "" $VECT_SLP_CFLAGS


[-- Attachment #2: rb17578.patch --]
[-- Type: application/octet-stream, Size: 21761 bytes --]

diff --git a/gcc/cp/cp-tree.h b/gcc/cp/cp-tree.h
index 8398223311194837441107cb335d497ff5f5ec1c..bece7bff1f01a23cfc94386fd3295a0be8c462fe 100644
--- a/gcc/cp/cp-tree.h
+++ b/gcc/cp/cp-tree.h
@@ -5377,6 +5377,7 @@ get_vec_init_expr (tree t)
 #define RANGE_FOR_UNROLL(NODE)	TREE_OPERAND (RANGE_FOR_STMT_CHECK (NODE), 4)
 #define RANGE_FOR_INIT_STMT(NODE) TREE_OPERAND (RANGE_FOR_STMT_CHECK (NODE), 5)
 #define RANGE_FOR_IVDEP(NODE)	TREE_LANG_FLAG_6 (RANGE_FOR_STMT_CHECK (NODE))
+#define RANGE_FOR_NOVECTOR(NODE) TREE_LANG_FLAG_5 (RANGE_FOR_STMT_CHECK (NODE))
 
 /* STMT_EXPR accessor.  */
 #define STMT_EXPR_STMT(NODE)	TREE_OPERAND (STMT_EXPR_CHECK (NODE), 0)
@@ -7286,7 +7287,7 @@ extern bool maybe_clone_body			(tree);
 
 /* In parser.cc */
 extern tree cp_convert_range_for (tree, tree, tree, tree, unsigned int, bool,
-				  unsigned short);
+				  unsigned short, bool);
 extern void cp_convert_omp_range_for (tree &, vec<tree, va_gc> *, tree &,
 				      tree &, tree &, tree &, tree &, tree &);
 extern void cp_finish_omp_range_for (tree, tree);
@@ -7609,16 +7610,19 @@ extern void begin_else_clause			(tree);
 extern void finish_else_clause			(tree);
 extern void finish_if_stmt			(tree);
 extern tree begin_while_stmt			(void);
-extern void finish_while_stmt_cond	(tree, tree, bool, unsigned short);
+extern void finish_while_stmt_cond	(tree, tree, bool, unsigned short,
+					 bool);
 extern void finish_while_stmt			(tree);
 extern tree begin_do_stmt			(void);
 extern void finish_do_body			(tree);
-extern void finish_do_stmt		(tree, tree, bool, unsigned short);
+extern void finish_do_stmt		(tree, tree, bool, unsigned short,
+					 bool);
 extern tree finish_return_stmt			(tree);
 extern tree begin_for_scope			(tree *);
 extern tree begin_for_stmt			(tree, tree);
 extern void finish_init_stmt			(tree);
-extern void finish_for_cond		(tree, tree, bool, unsigned short);
+extern void finish_for_cond		(tree, tree, bool, unsigned short,
+					 bool);
 extern void finish_for_expr			(tree, tree);
 extern void finish_for_stmt			(tree);
 extern tree begin_range_for_stmt		(tree, tree);
diff --git a/gcc/cp/init.cc b/gcc/cp/init.cc
index af6e30f511e142c7a594e742d128b2bf0aa8fb8d..5b735b27e6f5bc6b439ae64665902f4f1ca76f95 100644
--- a/gcc/cp/init.cc
+++ b/gcc/cp/init.cc
@@ -4846,7 +4846,7 @@ build_vec_init (tree base, tree maxindex, tree init,
       finish_init_stmt (for_stmt);
       finish_for_cond (build2 (GT_EXPR, boolean_type_node, iterator,
 			       build_int_cst (TREE_TYPE (iterator), -1)),
-		       for_stmt, false, 0);
+		       for_stmt, false, 0, false);
       /* We used to pass this decrement to finish_for_expr; now we add it to
 	 elt_init below so it's part of the same full-expression as the
 	 initialization, and thus happens before any potentially throwing
diff --git a/gcc/cp/method.cc b/gcc/cp/method.cc
index 91cf943f11089c0e6bcbe8377daa4e016f956d56..fce49c796199c2c65cd70684e2942fea1b6b2ebd 100644
--- a/gcc/cp/method.cc
+++ b/gcc/cp/method.cc
@@ -1645,7 +1645,8 @@ build_comparison_op (tree fndecl, bool defining, tsubst_flags_t complain)
 		      add_stmt (idx);
 		      finish_init_stmt (for_stmt);
 		      finish_for_cond (build2 (LE_EXPR, boolean_type_node, idx,
-					       maxval), for_stmt, false, 0);
+					       maxval), for_stmt, false, 0,
+					       false);
 		      finish_for_expr (cp_build_unary_op (PREINCREMENT_EXPR,
 							  TARGET_EXPR_SLOT (idx),
 							  false, complain),
diff --git a/gcc/cp/parser.cc b/gcc/cp/parser.cc
index dd3665c8ccf48a8a0b1ba2c06400fe50999ea240..092f991d7a1b6aab8482d50848fb9fb96c377509 100644
--- a/gcc/cp/parser.cc
+++ b/gcc/cp/parser.cc
@@ -2324,15 +2324,15 @@ static tree cp_parser_selection_statement
 static tree cp_parser_condition
   (cp_parser *);
 static tree cp_parser_iteration_statement
-  (cp_parser *, bool *, bool, unsigned short);
+  (cp_parser *, bool *, bool, unsigned short, bool);
 static bool cp_parser_init_statement
   (cp_parser *, tree *decl);
 static tree cp_parser_for
-  (cp_parser *, bool, unsigned short);
+  (cp_parser *, bool, unsigned short, bool);
 static tree cp_parser_c_for
-  (cp_parser *, tree, tree, bool, unsigned short);
+  (cp_parser *, tree, tree, bool, unsigned short, bool);
 static tree cp_parser_range_for
-  (cp_parser *, tree, tree, tree, bool, unsigned short, bool);
+  (cp_parser *, tree, tree, tree, bool, unsigned short, bool, bool);
 static void do_range_for_auto_deduction
   (tree, tree, tree, unsigned int);
 static tree cp_parser_perform_range_for_lookup
@@ -12414,7 +12414,8 @@ cp_parser_statement (cp_parser* parser, tree in_statement_expr,
 	case RID_DO:
 	case RID_FOR:
 	  std_attrs = process_stmt_hotness_attribute (std_attrs, attrs_loc);
-	  statement = cp_parser_iteration_statement (parser, if_p, false, 0);
+	  statement = cp_parser_iteration_statement (parser, if_p, false, 0,
+						     false);
 	  break;
 
 	case RID_BREAK:
@@ -13594,7 +13595,8 @@ cp_parser_condition (cp_parser* parser)
    not included. */
 
 static tree
-cp_parser_for (cp_parser *parser, bool ivdep, unsigned short unroll)
+cp_parser_for (cp_parser *parser, bool ivdep, unsigned short unroll,
+	       bool novector)
 {
   tree init, scope, decl;
   bool is_range_for;
@@ -13624,14 +13626,14 @@ cp_parser_for (cp_parser *parser, bool ivdep, unsigned short unroll)
 
   if (is_range_for)
     return cp_parser_range_for (parser, scope, init, decl, ivdep, unroll,
-				false);
+				novector, false);
   else
-    return cp_parser_c_for (parser, scope, init, ivdep, unroll);
+    return cp_parser_c_for (parser, scope, init, ivdep, unroll, novector);
 }
 
 static tree
 cp_parser_c_for (cp_parser *parser, tree scope, tree init, bool ivdep,
-		 unsigned short unroll)
+		 unsigned short unroll, bool novector)
 {
   /* Normal for loop */
   tree condition = NULL_TREE;
@@ -13658,7 +13660,7 @@ cp_parser_c_for (cp_parser *parser, tree scope, tree init, bool ivdep,
 		       "%<GCC unroll%> pragma");
       condition = error_mark_node;
     }
-  finish_for_cond (condition, stmt, ivdep, unroll);
+  finish_for_cond (condition, stmt, ivdep, unroll, novector);
   /* Look for the `;'.  */
   cp_parser_require (parser, CPP_SEMICOLON, RT_SEMICOLON);
 
@@ -13682,7 +13684,8 @@ cp_parser_c_for (cp_parser *parser, tree scope, tree init, bool ivdep,
 
 static tree
 cp_parser_range_for (cp_parser *parser, tree scope, tree init, tree range_decl,
-		     bool ivdep, unsigned short unroll, bool is_omp)
+		     bool ivdep, unsigned short unroll, bool novector,
+		     bool is_omp)
 {
   tree stmt, range_expr;
   auto_vec <cxx_binding *, 16> bindings;
@@ -13758,6 +13761,8 @@ cp_parser_range_for (cp_parser *parser, tree scope, tree init, tree range_decl,
 	RANGE_FOR_IVDEP (stmt) = 1;
       if (unroll)
 	RANGE_FOR_UNROLL (stmt) = build_int_cst (integer_type_node, unroll);
+      if (novector)
+	RANGE_FOR_NOVECTOR (stmt) = 1;
       finish_range_for_decl (stmt, range_decl, range_expr);
       if (!type_dependent_expression_p (range_expr)
 	  /* do_auto_deduction doesn't mess with template init-lists.  */
@@ -13770,7 +13775,7 @@ cp_parser_range_for (cp_parser *parser, tree scope, tree init, tree range_decl,
       stmt = begin_for_stmt (scope, init);
       stmt = cp_convert_range_for (stmt, range_decl, range_expr,
 				   decomp_first_name, decomp_cnt, ivdep,
-				   unroll);
+				   unroll, novector);
     }
   return stmt;
 }
@@ -13948,7 +13953,7 @@ warn_for_range_copy (tree decl, tree expr)
 tree
 cp_convert_range_for (tree statement, tree range_decl, tree range_expr,
 		      tree decomp_first_name, unsigned int decomp_cnt,
-		      bool ivdep, unsigned short unroll)
+		      bool ivdep, unsigned short unroll, bool novector)
 {
   tree begin, end;
   tree iter_type, begin_expr, end_expr;
@@ -14008,7 +14013,7 @@ cp_convert_range_for (tree statement, tree range_decl, tree range_expr,
 				 begin, ERROR_MARK,
 				 end, ERROR_MARK,
 				 NULL_TREE, NULL, tf_warning_or_error);
-  finish_for_cond (condition, statement, ivdep, unroll);
+  finish_for_cond (condition, statement, ivdep, unroll, novector);
 
   /* The new increment expression.  */
   expression = finish_unary_op_expr (input_location,
@@ -14175,7 +14180,7 @@ cp_parser_range_for_member_function (tree range, tree identifier)
 
 static tree
 cp_parser_iteration_statement (cp_parser* parser, bool *if_p, bool ivdep,
-			       unsigned short unroll)
+			       unsigned short unroll, bool novector)
 {
   cp_token *token;
   enum rid keyword;
@@ -14209,7 +14214,7 @@ cp_parser_iteration_statement (cp_parser* parser, bool *if_p, bool ivdep,
 	parens.require_open (parser);
 	/* Parse the condition.  */
 	condition = cp_parser_condition (parser);
-	finish_while_stmt_cond (condition, statement, ivdep, unroll);
+	finish_while_stmt_cond (condition, statement, ivdep, unroll, novector);
 	/* Look for the `)'.  */
 	parens.require_close (parser);
 	/* Parse the dependent statement.  */
@@ -14244,7 +14249,7 @@ cp_parser_iteration_statement (cp_parser* parser, bool *if_p, bool ivdep,
 	/* Parse the expression.  */
 	expression = cp_parser_expression (parser);
 	/* We're done with the do-statement.  */
-	finish_do_stmt (expression, statement, ivdep, unroll);
+	finish_do_stmt (expression, statement, ivdep, unroll, novector);
 	/* Look for the `)'.  */
 	parens.require_close (parser);
 	/* Look for the `;'.  */
@@ -14258,7 +14263,7 @@ cp_parser_iteration_statement (cp_parser* parser, bool *if_p, bool ivdep,
 	matching_parens parens;
 	parens.require_open (parser);
 
-	statement = cp_parser_for (parser, ivdep, unroll);
+	statement = cp_parser_for (parser, ivdep, unroll, novector);
 
 	/* Look for the `)'.  */
 	parens.require_close (parser);
@@ -43815,7 +43820,7 @@ cp_parser_omp_for_loop (cp_parser *parser, enum tree_code code, tree clauses,
 	      cp_parser_require (parser, CPP_COLON, RT_COLON);
 
 	      init = cp_parser_range_for (parser, NULL_TREE, NULL_TREE, decl,
-					  false, 0, true);
+					  false, 0, false, true);
 
 	      cp_convert_omp_range_for (this_pre_body, for_block, decl,
 					orig_decl, init, orig_init,
@@ -49300,6 +49305,15 @@ cp_parser_pragma_unroll (cp_parser *parser, cp_token *pragma_tok)
   return unroll;
 }
 
+/* Parse a pragma GCC novector.  */
+
+static bool
+cp_parser_pragma_novector (cp_parser *parser, cp_token *pragma_tok)
+{
+  cp_parser_skip_to_pragma_eol (parser, pragma_tok);
+  return true;
+}
+
 /* Normal parsing of a pragma token.  Here we can (and must) use the
    regular lexer.  */
 
@@ -49605,58 +49619,73 @@ cp_parser_pragma (cp_parser *parser, enum pragma_context context, bool *if_p)
       break;
 
     case PRAGMA_IVDEP:
+    case PRAGMA_UNROLL:
+    case PRAGMA_NOVECTOR:
       {
-	if (context == pragma_external)
+	bool ivdep;
+	unsigned short unroll = 0;
+	bool novector = false;
+	const char *pragma_str;
+
+	switch (id)
 	  {
-	    error_at (pragma_tok->location,
-		      "%<#pragma GCC ivdep%> must be inside a function");
+	  case PRAGMA_IVDEP:
+	    pragma_str = "ivdep";
 	    break;
-	  }
-	const bool ivdep = cp_parser_pragma_ivdep (parser, pragma_tok);
-	unsigned short unroll;
-	cp_token *tok = cp_lexer_peek_token (the_parser->lexer);
-	if (tok->type == CPP_PRAGMA
-	    && cp_parser_pragma_kind (tok) == PRAGMA_UNROLL)
-	  {
-	    tok = cp_lexer_consume_token (parser->lexer);
-	    unroll = cp_parser_pragma_unroll (parser, tok);
-	    tok = cp_lexer_peek_token (the_parser->lexer);
-	  }
-	else
-	  unroll = 0;
-	if (tok->type != CPP_KEYWORD
-	    || (tok->keyword != RID_FOR
-		&& tok->keyword != RID_WHILE
-		&& tok->keyword != RID_DO))
-	  {
-	    cp_parser_error (parser, "for, while or do statement expected");
-	    return false;
-	  }
-	cp_parser_iteration_statement (parser, if_p, ivdep, unroll);
-	return true;
-      }
+	  case PRAGMA_UNROLL:
+	    pragma_str = "unroll";
+	    break;
+	  case PRAGMA_NOVECTOR:
+	    pragma_str = "novector";
+	    break;
+	  default:
+	    gcc_unreachable ();
+	}
 
-    case PRAGMA_UNROLL:
-      {
 	if (context == pragma_external)
 	  {
 	    error_at (pragma_tok->location,
-		      "%<#pragma GCC unroll%> must be inside a function");
+		      "%<#pragma GCC %s%> must be inside a function",
+		      pragma_str);
 	    break;
 	  }
-	const unsigned short unroll
-	  = cp_parser_pragma_unroll (parser, pragma_tok);
-	bool ivdep;
-	cp_token *tok = cp_lexer_peek_token (the_parser->lexer);
-	if (tok->type == CPP_PRAGMA
-	    && cp_parser_pragma_kind (tok) == PRAGMA_IVDEP)
+
+	cp_token *tok = pragma_tok;
+	bool has_more = true;
+	do
 	  {
-	    tok = cp_lexer_consume_token (parser->lexer);
-	    ivdep = cp_parser_pragma_ivdep (parser, tok);
+	    switch (cp_parser_pragma_kind (tok))
+	      {
+		case PRAGMA_IVDEP:
+		  {
+		    if (tok != pragma_tok)
+		      tok = cp_lexer_consume_token (parser->lexer);
+		    ivdep = cp_parser_pragma_ivdep (parser, tok);
+		    break;
+		  }
+		case PRAGMA_UNROLL:
+		  {
+		    if (tok != pragma_tok)
+		      tok = cp_lexer_consume_token (parser->lexer);
+		    unroll = cp_parser_pragma_unroll (parser, tok);
+		    break;
+		  }
+		case PRAGMA_NOVECTOR:
+		  {
+		    if (tok != pragma_tok)
+		      tok = cp_lexer_consume_token (parser->lexer);
+		    novector = cp_parser_pragma_novector (parser, tok);
+		    break;
+		  }
+		default:
+		  has_more = false;
+		  break;
+	      }
 	    tok = cp_lexer_peek_token (the_parser->lexer);
+	    has_more = has_more && tok->type == CPP_PRAGMA;
 	  }
-	else
-	  ivdep = false;
+	while (has_more);
+
 	if (tok->type != CPP_KEYWORD
 	    || (tok->keyword != RID_FOR
 		&& tok->keyword != RID_WHILE
@@ -49665,7 +49694,7 @@ cp_parser_pragma (cp_parser *parser, enum pragma_context context, bool *if_p)
 	    cp_parser_error (parser, "for, while or do statement expected");
 	    return false;
 	  }
-	cp_parser_iteration_statement (parser, if_p, ivdep, unroll);
+	cp_parser_iteration_statement (parser, if_p, ivdep, unroll, novector);
 	return true;
       }
 
diff --git a/gcc/cp/pt.cc b/gcc/cp/pt.cc
index 2345a18becc1160b9d12f3d88cccb66c8917373c..7b0d01a90e3c4012ec603ebe04cbbb31a7dd1570 100644
--- a/gcc/cp/pt.cc
+++ b/gcc/cp/pt.cc
@@ -19036,7 +19036,7 @@ tsubst_expr (tree t, tree args, tsubst_flags_t complain, tree in_decl)
       RECUR (FOR_INIT_STMT (t));
       finish_init_stmt (stmt);
       tmp = RECUR (FOR_COND (t));
-      finish_for_cond (tmp, stmt, false, 0);
+      finish_for_cond (tmp, stmt, false, 0, false);
       tmp = RECUR (FOR_EXPR (t));
       finish_for_expr (tmp, stmt);
       {
@@ -19073,6 +19073,7 @@ tsubst_expr (tree t, tree args, tsubst_flags_t complain, tree in_decl)
 	  {
 	    RANGE_FOR_IVDEP (stmt) = RANGE_FOR_IVDEP (t);
 	    RANGE_FOR_UNROLL (stmt) = RANGE_FOR_UNROLL (t);
+	    RANGE_FOR_NOVECTOR (stmt) = RANGE_FOR_NOVECTOR (t);
 	    finish_range_for_decl (stmt, decl, expr);
 	    if (decomp_first && decl != error_mark_node)
 	      cp_finish_decomp (decl, decomp_first, decomp_cnt);
@@ -19083,7 +19084,8 @@ tsubst_expr (tree t, tree args, tsubst_flags_t complain, tree in_decl)
 				     ? tree_to_uhwi (RANGE_FOR_UNROLL (t)) : 0);
 	    stmt = cp_convert_range_for (stmt, decl, expr,
 					 decomp_first, decomp_cnt,
-					 RANGE_FOR_IVDEP (t), unroll);
+					 RANGE_FOR_IVDEP (t), unroll,
+					 RANGE_FOR_NOVECTOR (t));
 	  }
 
 	bool prev = note_iteration_stmt_body_start ();
@@ -19096,7 +19098,7 @@ tsubst_expr (tree t, tree args, tsubst_flags_t complain, tree in_decl)
     case WHILE_STMT:
       stmt = begin_while_stmt ();
       tmp = RECUR (WHILE_COND (t));
-      finish_while_stmt_cond (tmp, stmt, false, 0);
+      finish_while_stmt_cond (tmp, stmt, false, 0, false);
       {
 	bool prev = note_iteration_stmt_body_start ();
 	RECUR (WHILE_BODY (t));
@@ -19114,7 +19116,7 @@ tsubst_expr (tree t, tree args, tsubst_flags_t complain, tree in_decl)
       }
       finish_do_body (stmt);
       tmp = RECUR (DO_COND (t));
-      finish_do_stmt (tmp, stmt, false, 0);
+      finish_do_stmt (tmp, stmt, false, 0, false);
       break;
 
     case IF_STMT:
diff --git a/gcc/cp/semantics.cc b/gcc/cp/semantics.cc
index 8fb47fd179eb2af2e82bf31d188023e9b9d41de9..b79975109c22ebcfcb060b4f20f32f69f3c3c444 100644
--- a/gcc/cp/semantics.cc
+++ b/gcc/cp/semantics.cc
@@ -1148,7 +1148,7 @@ begin_while_stmt (void)
 
 void
 finish_while_stmt_cond (tree cond, tree while_stmt, bool ivdep,
-			unsigned short unroll)
+			unsigned short unroll, bool novector)
 {
   cond = maybe_convert_cond (cond);
   finish_cond (&WHILE_COND (while_stmt), cond);
@@ -1168,6 +1168,13 @@ finish_while_stmt_cond (tree cond, tree while_stmt, bool ivdep,
 						     annot_expr_unroll_kind),
 				      build_int_cst (integer_type_node,
 						     unroll));
+  if (novector && cond != error_mark_node)
+    WHILE_COND (while_stmt) = build3 (ANNOTATE_EXPR,
+				      TREE_TYPE (WHILE_COND (while_stmt)),
+				      WHILE_COND (while_stmt),
+				      build_int_cst (integer_type_node,
+						     annot_expr_no_vector_kind),
+				      integer_zero_node);
   simplify_loop_decl_cond (&WHILE_COND (while_stmt), WHILE_BODY (while_stmt));
 }
 
@@ -1212,7 +1219,8 @@ finish_do_body (tree do_stmt)
    COND is as indicated.  */
 
 void
-finish_do_stmt (tree cond, tree do_stmt, bool ivdep, unsigned short unroll)
+finish_do_stmt (tree cond, tree do_stmt, bool ivdep, unsigned short unroll,
+		bool novector)
 {
   cond = maybe_convert_cond (cond);
   end_maybe_infinite_loop (cond);
@@ -1229,6 +1237,10 @@ finish_do_stmt (tree cond, tree do_stmt, bool ivdep, unsigned short unroll)
     cond = build3 (ANNOTATE_EXPR, TREE_TYPE (cond), cond,
 		   build_int_cst (integer_type_node, annot_expr_unroll_kind),
 		   build_int_cst (integer_type_node, unroll));
+  if (novector && cond != error_mark_node)
+    cond = build3 (ANNOTATE_EXPR, TREE_TYPE (cond), cond,
+		   build_int_cst (integer_type_node, annot_expr_no_vector_kind),
+		   integer_zero_node);
   DO_COND (do_stmt) = cond;
 }
 
@@ -1325,7 +1337,7 @@ finish_init_stmt (tree for_stmt)
    FOR_STMT.  */
 
 void
-finish_for_cond (tree cond, tree for_stmt, bool ivdep, unsigned short unroll)
+finish_for_cond (tree cond, tree for_stmt, bool ivdep, unsigned short unroll, bool novector)
 {
   cond = maybe_convert_cond (cond);
   finish_cond (&FOR_COND (for_stmt), cond);
@@ -1345,6 +1357,13 @@ finish_for_cond (tree cond, tree for_stmt, bool ivdep, unsigned short unroll)
 						 annot_expr_unroll_kind),
 				  build_int_cst (integer_type_node,
 						 unroll));
+  if (novector && cond != error_mark_node)
+    FOR_COND (for_stmt) = build3 (ANNOTATE_EXPR,
+				  TREE_TYPE (FOR_COND (for_stmt)),
+				  FOR_COND (for_stmt),
+				  build_int_cst (integer_type_node,
+						 annot_expr_no_vector_kind),
+				  integer_zero_node);
   simplify_loop_decl_cond (&FOR_COND (for_stmt), FOR_BODY (for_stmt));
 }
 
diff --git a/gcc/doc/extend.texi b/gcc/doc/extend.texi
index 3040a9bdea65d27f8d20572b4ed37375f5fe949b..baac6643d1abbf33d592e68aca49ac83e3c29188 100644
--- a/gcc/doc/extend.texi
+++ b/gcc/doc/extend.texi
@@ -24349,6 +24349,25 @@ void ignore_vec_dep (int *a, int k, int c, int m)
 @}
 @end smallexample
 
+@cindex pragma GCC novector
+@item #pragma GCC novector
+
+With this pragma, the programmer asserts that the following loop should be
+prevented from executing concurrently with SIMD (single instruction multiple
+data) instructions.
+
+For example, the compiler cannot vectorize the following loop with the pragma:
+
+@smallexample
+void foo (int n, int *a, int *b, int *c)
+@{
+  int i, j;
+#pragma GCC novector
+  for (i = 0; i < n; ++i)
+    a[i] = b[i] + c[i];
+@}
+@end smallexample
+
 @cindex pragma GCC unroll @var{n}
 @item #pragma GCC unroll @var{n}
 
diff --git a/gcc/testsuite/g++.dg/vect/vect-novector-pragma.cc b/gcc/testsuite/g++.dg/vect/vect-novector-pragma.cc
new file mode 100644
index 0000000000000000000000000000000000000000..8c6ff22fcaabaa97516be72b77acbd44df86b1d2
--- /dev/null
+++ b/gcc/testsuite/g++.dg/vect/vect-novector-pragma.cc
@@ -0,0 +1,69 @@
+/* { dg-do compile } */
+/* { dg-require-effective-target vect_int } */
+
+#include <vector>
+
+void f4 (std::vector<int> a, std::vector<int> b, int n)
+{
+    int i = 0;
+#pragma GCC novector
+    while (i < (n & -8))
+      {
+        a[i] += b[i];
+        i++;
+      }
+}
+
+void f5 (std::vector<int> a, std::vector<int> b, int n)
+{
+    int i = 0;
+#pragma GCC novector
+#pragma GCC ivdep
+#pragma GCC unroll 2
+    while (i < (n & -8))
+      {
+        a[i] += b[i];
+        i++;
+      }
+}
+
+void f6 (std::vector<int> a, std::vector<int> b, int n)
+{
+    int i = 0;
+#pragma GCC ivdep
+#pragma GCC novector
+#pragma GCC unroll 2
+    while (i < (n & -8))
+      {
+        a[i] += b[i];
+        i++;
+      }
+}
+
+void f7 (std::vector<int> a, std::vector<int> b, int n)
+{
+    int i = 0;
+#pragma GCC ivdep
+#pragma GCC unroll 2
+#pragma GCC novector
+    while (i < (n & -8))
+      {
+        a[i] += b[i];
+        i++;
+      }
+}
+
+#if __cpp_range_based_for
+void f8 (std::vector<int> a, std::vector<int> b, int n)
+{
+    int i = 0;
+#pragma GCC novector
+    for (int x : b)
+      {
+        a[i] += x;
+        i++;
+      }
+}
+#endif
+
+/* { dg-final { scan-tree-dump-not "LOOP VECTORIZED" "vect" } } */
diff --git a/gcc/testsuite/g++.dg/vect/vect.exp b/gcc/testsuite/g++.dg/vect/vect.exp
index df273233f47a788024bbe61128eaa96b639cb3b8..fc77120a83173c65ad147e8bb7c29ac82f06bb6d 100644
--- a/gcc/testsuite/g++.dg/vect/vect.exp
+++ b/gcc/testsuite/g++.dg/vect/vect.exp
@@ -64,7 +64,7 @@ dg-init
 
 # Main loop.
 et-dg-runtest g++-dg-runtest [lsort [glob -nocomplain \
-	$srcdir/$subdir/{pr,simd}*.{c,cc,S} ]] "" $DEFAULT_VECTCFLAGS
+	$srcdir/$subdir/{pr,simd,vect-}*.{c,cc,S} ]] "" $DEFAULT_VECTCFLAGS
 et-dg-runtest g++-dg-runtest [lsort [glob -nocomplain \
 	$srcdir/$subdir/slp-pr*.{c,cc,S} ]] "" $VECT_SLP_CFLAGS