Merge from trunk revision 8e4a738d2540ab6aff77506d368bf4e3fa6963bd.

19 files changed, 294 insertions, 42 deletions

diff --git a/gcc/c/ChangeLog b/gcc/c/ChangeLog
index b97fb74..9afa103 100644
--- a/gcc/c/ChangeLog
+++ b/gcc/c/ChangeLog
@@ -1,3 +1,64 @@
+2021-02-01  Martin Sebor  <msebor@redhat.com>
+
+	PR middle-end/97172
+	* c-decl.c (free_attr_access_data): New function.
+	(c_parse_final_cleanups): Call free_attr_access_data.
+
+2021-01-16  Kwok Cheung Yeung  <kcy@codesourcery.com>
+
+	* c-parser.c (c_parser_omp_clause_detach): New.
+	(c_parser_omp_all_clauses): Handle PRAGMA_OMP_CLAUSE_DETACH clause.
+	(OMP_TASK_CLAUSE_MASK): Add mask for PRAGMA_OMP_CLAUSE_DETACH.
+	* c-typeck.c (c_finish_omp_clauses): Handle PRAGMA_OMP_CLAUSE_DETACH
+	clause.  Prevent use of detach with mergeable and overriding the
+	data sharing mode of the event handle.
+
+2021-01-15  Jakub Jelinek  <jakub@redhat.com>
+
+	* c-typeck.c (c_finish_omp_clauses): For reduction build array with
+	unqualified element type and then call c_build_qualified_type on the
+	ARRAY_TYPE.
+
+2021-01-07  Richard Biener  <rguenther@suse.de>
+
+	* gimple-parser.c (c_parser_gimple_compound_statement): Only
+	reallocate loop array if it is too small.
+
+2020-12-16  Martin Uecker  <muecker@gwdg.de>
+
+	PR c/98047
+	* c-typeck.c (build_modify_expr): Drop qualifiers.
+
+2020-12-16  Martin Uecker  <muecker@gwdg.de>
+
+	PR c/98260
+	* c-parser.c (c_parser_expression): Look into
+	nop expression when marking expressions as read.
+
+2020-12-14  Martin Liska  <mliska@suse.cz>
+
+	PR sanitizer/98204
+	* c-typeck.c (pointer_diff): Do not emit a top-level
+	sanitization.
+	(build_binary_op): Likewise.
+
+2020-12-09  Tobias Burnus  <tobias@codesourcery.com>
+
+	* c-parser.c (c_parser_omp_allocate): New.
+	(c_parser_omp_construct): Call it.
+
+2020-12-09  Richard Biener  <rguenther@suse.de>
+
+	PR c/98200
+	* gimple-parser.c (c_parser_gimple_postfix_expression): Return
+	early on error.
+
+2020-12-07  Martin Uecker  <muecker@gwdg.de>
+
+	PR c/97981
+	* c-typeck.c (convert_lvalue_to_rvalue): Move the code
+	that drops qualifiers to the end of the function.
+
 2020-11-26  Martin Uecker  <muecker@gwdg.de>
 
 	PR c/65455
@@ -7396,7 +7457,7 @@
 	* c-decl.c: Likewise.  Include gt-c-c-decl.h, not gt-c-decl.h.
 	* c-parser.c: Likewise.  Include gt-c-c-parser.h, not gt-c-parser.h.
 
-Copyright (C) 2012-2020 Free Software Foundation, Inc.
+Copyright (C) 2012-2021 Free Software Foundation, Inc.
 
 Copying and distribution of this file, with or without modification,
 are permitted in any medium without royalty provided the copyright
diff --git a/gcc/c/Make-lang.in b/gcc/c/Make-lang.in
index 4b2e616..a1cdee8 100644
--- a/gcc/c/Make-lang.in
+++ b/gcc/c/Make-lang.in
@@ -1,5 +1,5 @@
 # Top level -*- makefile -*- fragment for GNU C - C language.
-# Copyright (C) 1994-2020 Free Software Foundation, Inc.
+# Copyright (C) 1994-2021 Free Software Foundation, Inc.
 
 #This file is part of GCC.
 
diff --git a/gcc/c/c-aux-info.c b/gcc/c/c-aux-info.c
index bdeef52..bae5757 100644
--- a/gcc/c/c-aux-info.c
+++ b/gcc/c/c-aux-info.c
@@ -1,7 +1,7 @@
 /* Generate information regarding function declarations and definitions based
    on information stored in GCC's tree structure.  This code implements the
    -aux-info option.
-   Copyright (C) 1989-2020 Free Software Foundation, Inc.
+   Copyright (C) 1989-2021 Free Software Foundation, Inc.
    Contributed by Ron Guilmette (rfg@segfault.us.com).
 
 This file is part of GCC.
diff --git a/gcc/c/c-convert.c b/gcc/c/c-convert.c
index 8f0982d..d0035a3 100644
--- a/gcc/c/c-convert.c
+++ b/gcc/c/c-convert.c
@@ -1,5 +1,5 @@
 /* Language-level data type conversion for GNU C.
-   Copyright (C) 1987-2020 Free Software Foundation, Inc.
+   Copyright (C) 1987-2021 Free Software Foundation, Inc.
 
 This file is part of GCC.
 
diff --git a/gcc/c/c-decl.c b/gcc/c/c-decl.c
index 27f7722..be95643 100644
--- a/gcc/c/c-decl.c
+++ b/gcc/c/c-decl.c
@@ -1,5 +1,5 @@
 /* Process declarations and variables for C compiler.
-   Copyright (C) 1988-2020 Free Software Foundation, Inc.
+   Copyright (C) 1988-2021 Free Software Foundation, Inc.
 
 This file is part of GCC.
 
@@ -12146,6 +12146,27 @@ collect_source_refs (void)
       collect_source_ref (DECL_SOURCE_FILE (decl));
 }
 
+/* Free attribute access data that are not needed by the middle end. */
+
+static void
+free_attr_access_data ()
+{
+  struct cgraph_node *n;
+
+  /* Iterate over all functions declared in the translation unit.  */
+  FOR_EACH_FUNCTION (n)
+    {
+      tree fntype = TREE_TYPE (n->decl);
+      if (!fntype)
+	continue;
+      tree attrs = TYPE_ATTRIBUTES (fntype);
+      if (!attrs)
+	continue;
+
+      attr_access::free_lang_data (attrs);
+    }
+}
+
 /* Perform any final parser cleanups and generate initial debugging
    information.  */
 
@@ -12190,6 +12211,9 @@ c_parse_final_cleanups (void)
     c_write_global_declarations_1 (BLOCK_VARS (DECL_INITIAL (t)));
   c_write_global_declarations_1 (BLOCK_VARS (ext_block));
 
+  if (!in_lto_p)
+    free_attr_access_data ();
+
   timevar_stop (TV_PHASE_DEFERRED);
   timevar_start (TV_PHASE_PARSING);
 
diff --git a/gcc/c/c-errors.c b/gcc/c/c-errors.c
index d90587c..de98958 100644
--- a/gcc/c/c-errors.c
+++ b/gcc/c/c-errors.c
@@ -1,5 +1,5 @@
 /* Various diagnostic subroutines for the GNU C language.
-   Copyright (C) 2000-2020 Free Software Foundation, Inc.
+   Copyright (C) 2000-2021 Free Software Foundation, Inc.
    Contributed by Gabriel Dos Reis <gdr@codesourcery.com>
 
 This file is part of GCC.
diff --git a/gcc/c/c-fold.c b/gcc/c/c-fold.c
index bd21d24..68c74cc 100644
--- a/gcc/c/c-fold.c
+++ b/gcc/c/c-fold.c
@@ -1,5 +1,5 @@
 /* Support for fully folding sub-trees of an expression for C compiler.
-   Copyright (C) 1992-2020 Free Software Foundation, Inc.
+   Copyright (C) 1992-2021 Free Software Foundation, Inc.
 
 This file is part of GCC.
 
diff --git a/gcc/c/c-lang.c b/gcc/c/c-lang.c
index 5d52c42..778a6f2 100644
--- a/gcc/c/c-lang.c
+++ b/gcc/c/c-lang.c
@@ -1,5 +1,5 @@
 /* Language-specific hook definitions for C front end.
-   Copyright (C) 1991-2020 Free Software Foundation, Inc.
+   Copyright (C) 1991-2021 Free Software Foundation, Inc.
 
 This file is part of GCC.
 
diff --git a/gcc/c/c-lang.h b/gcc/c/c-lang.h
index 7e9a276..2f62ee1 100644
--- a/gcc/c/c-lang.h
+++ b/gcc/c/c-lang.h
@@ -1,5 +1,5 @@
 /* Definitions for C language specific types.
-   Copyright (C) 2009-2020 Free Software Foundation, Inc.
+   Copyright (C) 2009-2021 Free Software Foundation, Inc.
 
 This file is part of GCC.
 
diff --git a/gcc/c/c-objc-common.c b/gcc/c/c-objc-common.c
index 378288f..a68249d 100644
--- a/gcc/c/c-objc-common.c
+++ b/gcc/c/c-objc-common.c
@@ -1,5 +1,5 @@
 /* Some code common to C and ObjC front ends.
-   Copyright (C) 2001-2020 Free Software Foundation, Inc.
+   Copyright (C) 2001-2021 Free Software Foundation, Inc.
 
 This file is part of GCC.
 
diff --git a/gcc/c/c-objc-common.h b/gcc/c/c-objc-common.h
index 76f9db7..7d35a06 100644
--- a/gcc/c/c-objc-common.h
+++ b/gcc/c/c-objc-common.h
@@ -1,5 +1,5 @@
 /* Language hooks common to C and ObjC front ends.
-   Copyright (C) 2004-2020 Free Software Foundation, Inc.
+   Copyright (C) 2004-2021 Free Software Foundation, Inc.
    Contributed by Ziemowit Laski  <zlaski@apple.com>
 
 This file is part of GCC.
diff --git a/gcc/c/c-parser.c b/gcc/c/c-parser.c
index 87ee8f4..a8df208 100644
--- a/gcc/c/c-parser.c
+++ b/gcc/c/c-parser.c
@@ -1,5 +1,5 @@
 /* Parser for C and Objective-C.
-   Copyright (C) 1987-2020 Free Software Foundation, Inc.
+   Copyright (C) 1987-2021 Free Software Foundation, Inc.
 
    Parser actions based on the old Bison parser; structure somewhat
    influenced by and fragments based on the C++ parser.
@@ -10615,8 +10615,14 @@ c_parser_expression (c_parser *parser)
       c_parser_consume_token (parser);
       expr_loc = c_parser_peek_token (parser)->location;
       lhsval = expr.value;
-      while (TREE_CODE (lhsval) == COMPOUND_EXPR)
-	lhsval = TREE_OPERAND (lhsval, 1);
+      while (TREE_CODE (lhsval) == COMPOUND_EXPR
+	     || TREE_CODE (lhsval) == NOP_EXPR)
+	{
+	  if (TREE_CODE (lhsval) == COMPOUND_EXPR)
+	    lhsval = TREE_OPERAND (lhsval, 1);
+	  else
+	    lhsval = TREE_OPERAND (lhsval, 0);
+	}
       if (DECL_P (lhsval) || handled_component_p (lhsval))
 	mark_exp_read (lhsval);
       next = c_parser_expr_no_commas (parser, NULL);
@@ -15971,6 +15977,56 @@ c_parser_omp_clause_uniform (c_parser *parser, tree list)
   return list;
 }
 
+/* OpenMP 5.0:
+   detach ( event-handle ) */
+
+static tree
+c_parser_omp_clause_detach (c_parser *parser, tree list)
+{
+  matching_parens parens;
+  location_t clause_loc = c_parser_peek_token (parser)->location;
+
+  if (!parens.require_open (parser))
+    return list;
+
+  if (c_parser_next_token_is_not (parser, CPP_NAME)
+      || c_parser_peek_token (parser)->id_kind != C_ID_ID)
+    {
+      c_parser_error (parser, "expected identifier");
+      parens.skip_until_found_close (parser);
+      return list;
+    }
+
+  tree t = lookup_name (c_parser_peek_token (parser)->value);
+  if (t == NULL_TREE)
+    {
+      undeclared_variable (c_parser_peek_token (parser)->location,
+			   c_parser_peek_token (parser)->value);
+      parens.skip_until_found_close (parser);
+      return list;
+    }
+  c_parser_consume_token (parser);
+
+  tree type = TYPE_MAIN_VARIANT (TREE_TYPE (t));
+  if (!INTEGRAL_TYPE_P (type)
+      || TREE_CODE (type) != ENUMERAL_TYPE
+      || TYPE_NAME (type) != get_identifier ("omp_event_handle_t"))
+    {
+      error_at (clause_loc, "%<detach%> clause event handle "
+			    "has type %qT rather than "
+			    "%<omp_event_handle_t%>",
+			    type);
+      parens.skip_until_found_close (parser);
+      return list;
+    }
+
+  tree u = build_omp_clause (clause_loc, OMP_CLAUSE_DETACH);
+  OMP_CLAUSE_DECL (u) = t;
+  OMP_CLAUSE_CHAIN (u) = list;
+  parens.skip_until_found_close (parser);
+  return u;
+}
+
 /* Parse all OpenACC clauses.  The set clauses allowed by the directive
    is a bitmask in MASK.  Return the list of clauses found.  */
 
@@ -16237,6 +16293,10 @@ c_parser_omp_all_clauses (c_parser *parser, omp_clause_mask mask,
 	  clauses = c_parser_omp_clause_default (parser, clauses, false);
 	  c_name = "default";
 	  break;
+	case PRAGMA_OMP_CLAUSE_DETACH:
+	  clauses = c_parser_omp_clause_detach (parser, clauses);
+	  c_name = "detach";
+	  break;
 	case PRAGMA_OMP_CLAUSE_FIRSTPRIVATE:
 	  clauses = c_parser_omp_clause_firstprivate (parser, clauses);
 	  c_name = "firstprivate";
@@ -17250,6 +17310,55 @@ c_parser_oacc_wait (location_t loc, c_parser *parser, char *p_name)
   return stmt;
 }
 
+/* OpenMP 5.0:
+   # pragma omp allocate (list)  [allocator(allocator)]  */
+
+static void
+c_parser_omp_allocate (location_t loc, c_parser *parser)
+{
+  tree allocator = NULL_TREE;
+  tree nl = c_parser_omp_var_list_parens (parser, OMP_CLAUSE_ALLOCATE, NULL_TREE);
+  if (c_parser_next_token_is (parser, CPP_NAME))
+    {
+      matching_parens parens;
+      const char *p = IDENTIFIER_POINTER (c_parser_peek_token (parser)->value);
+      c_parser_consume_token (parser);
+      if (strcmp ("allocator", p) != 0)
+	error_at (c_parser_peek_token (parser)->location,
+		  "expected %<allocator%>");
+      else if (parens.require_open (parser))
+	{
+	  location_t expr_loc = c_parser_peek_token (parser)->location;
+	  c_expr expr = c_parser_expr_no_commas (parser, NULL);
+	  expr = convert_lvalue_to_rvalue (expr_loc, expr, false, true);
+	  allocator = expr.value;
+	  allocator = c_fully_fold (allocator, false, NULL);
+	  tree orig_type
+	    = expr.original_type ? expr.original_type : TREE_TYPE (allocator);
+	  orig_type = TYPE_MAIN_VARIANT (orig_type);
+	  if (!INTEGRAL_TYPE_P (TREE_TYPE (allocator))
+	      || TREE_CODE (orig_type) != ENUMERAL_TYPE
+	      || TYPE_NAME (orig_type)
+		 != get_identifier ("omp_allocator_handle_t"))
+	    {
+	      error_at (expr_loc, "%<allocator%> clause allocator expression "
+				"has type %qT rather than "
+				"%<omp_allocator_handle_t%>",
+				TREE_TYPE (allocator));
+	      allocator = NULL_TREE;
+	    }
+	  parens.skip_until_found_close (parser);
+	}
+    }
+  c_parser_skip_to_pragma_eol (parser);
+
+  if (allocator)
+    for (tree c = nl; c != NULL_TREE; c = OMP_CLAUSE_CHAIN (c))
+      OMP_CLAUSE_ALLOCATE_ALLOCATOR (c) = allocator;
+
+  sorry_at (loc, "%<#pragma omp allocate%> not yet supported");
+}
+
 /* OpenMP 2.5:
    # pragma omp atomic new-line
      expression-stmt
@@ -19135,7 +19244,8 @@ c_parser_omp_single (location_t loc, c_parser *parser, bool *if_p)
 	| (OMP_CLAUSE_MASK_1 << PRAGMA_OMP_CLAUSE_DEPEND)	\
 	| (OMP_CLAUSE_MASK_1 << PRAGMA_OMP_CLAUSE_PRIORITY)	\
 	| (OMP_CLAUSE_MASK_1 << PRAGMA_OMP_CLAUSE_ALLOCATE)	\
-	| (OMP_CLAUSE_MASK_1 << PRAGMA_OMP_CLAUSE_IN_REDUCTION))
+	| (OMP_CLAUSE_MASK_1 << PRAGMA_OMP_CLAUSE_IN_REDUCTION)	\
+	| (OMP_CLAUSE_MASK_1 << PRAGMA_OMP_CLAUSE_DETACH))
 
 static tree
 c_parser_omp_task (location_t loc, c_parser *parser, bool *if_p)
@@ -21537,6 +21647,9 @@ c_parser_omp_construct (c_parser *parser, bool *if_p)
       strcpy (p_name, "#pragma wait");
       stmt = c_parser_oacc_wait (loc, parser, p_name);
       break;
+    case PRAGMA_OMP_ALLOCATE:
+      c_parser_omp_allocate (loc, parser);
+      return;
     case PRAGMA_OMP_ATOMIC:
       c_parser_omp_atomic (loc, parser, false);
       return;
diff --git a/gcc/c/c-parser.h b/gcc/c/c-parser.h
index bf9e75e..773aa43 100644
--- a/gcc/c/c-parser.h
+++ b/gcc/c/c-parser.h
@@ -1,5 +1,5 @@
 /* Declarations for the parser for C and Objective-C.
-   Copyright (C) 1987-2020 Free Software Foundation, Inc.
+   Copyright (C) 1987-2021 Free Software Foundation, Inc.
 
    Parser actions based on the old Bison parser; structure somewhat
    influenced by and fragments based on the C++ parser.
diff --git a/gcc/c/c-tree.h b/gcc/c/c-tree.h
index 1f783db..a671a3e 100644
--- a/gcc/c/c-tree.h
+++ b/gcc/c/c-tree.h
@@ -1,5 +1,5 @@
 /* Definitions for C parsing and type checking.
-   Copyright (C) 1987-2020 Free Software Foundation, Inc.
+   Copyright (C) 1987-2021 Free Software Foundation, Inc.
 
 This file is part of GCC.
 
diff --git a/gcc/c/c-typeck.c b/gcc/c/c-typeck.c
index cdc491a..8ef0843 100644
--- a/gcc/c/c-typeck.c
+++ b/gcc/c/c-typeck.c
@@ -1,5 +1,5 @@
 /* Build expressions with type checking for C compiler.
-   Copyright (C) 1987-2020 Free Software Foundation, Inc.
+   Copyright (C) 1987-2021 Free Software Foundation, Inc.
 
 This file is part of GCC.
 
@@ -2080,9 +2080,6 @@ convert_lvalue_to_rvalue (location_t loc, struct c_expr exp,
     exp = default_function_array_conversion (loc, exp);
   if (!VOID_TYPE_P (TREE_TYPE (exp.value)))
     exp.value = require_complete_type (loc, exp.value);
-  if (convert_p && !error_operand_p (exp.value)
-      && (TREE_CODE (TREE_TYPE (exp.value)) != ARRAY_TYPE))
-    exp.value = convert (build_qualified_type (TREE_TYPE (exp.value), TYPE_UNQUALIFIED), exp.value);
   if (really_atomic_lvalue (exp.value))
     {
       vec<tree, va_gc> *params;
@@ -2119,6 +2116,9 @@ convert_lvalue_to_rvalue (location_t loc, struct c_expr exp,
       exp.value = build4 (TARGET_EXPR, nonatomic_type, tmp, func_call,
 			  NULL_TREE, NULL_TREE);
     }
+  if (convert_p && !error_operand_p (exp.value)
+      && (TREE_CODE (TREE_TYPE (exp.value)) != ARRAY_TYPE))
+    exp.value = convert (build_qualified_type (TREE_TYPE (exp.value), TYPE_UNQUALIFIED), exp.value);
   return exp;
 }
 
@@ -3949,10 +3949,9 @@ pointer_diff (location_t loc, tree op0, tree op1, tree *instrument_expr)
     pedwarn (loc, OPT_Wpointer_arith,
 	     "pointer to a function used in subtraction");
 
-  if (sanitize_flags_p (SANITIZE_POINTER_SUBTRACT))
+  if (current_function_decl != NULL_TREE
+      && sanitize_flags_p (SANITIZE_POINTER_SUBTRACT))
     {
-      gcc_assert (current_function_decl != NULL_TREE);
-
       op0 = save_expr (op0);
       op1 = save_expr (op1);
 
@@ -6276,16 +6275,9 @@ build_modify_expr (location_t location, tree lhs, tree lhs_origtype,
 		    "enum conversion in assignment is invalid in C++");
     }
 
-  /* If the lhs is atomic, remove that qualifier.  */
-  if (is_atomic_op)
-    {
-      lhstype = build_qualified_type (lhstype, 
-				      (TYPE_QUALS (lhstype)
-				       & ~TYPE_QUAL_ATOMIC));
-      olhstype = build_qualified_type (olhstype, 
-				       (TYPE_QUALS (lhstype)
-					& ~TYPE_QUAL_ATOMIC));
-    }
+  /* Remove qualifiers.  */
+  lhstype = build_qualified_type (lhstype, TYPE_UNQUALIFIED);
+  olhstype = build_qualified_type (olhstype, TYPE_UNQUALIFIED);
 
   /* Convert new value to destination type.  Fold it first, then
      restore any excess precision information, for the sake of
@@ -12324,6 +12316,7 @@ build_binary_op (location_t location, enum tree_code code,
 	}
 
       if ((code0 == POINTER_TYPE || code1 == POINTER_TYPE)
+	  && current_function_decl != NULL_TREE
 	  && sanitize_flags_p (SANITIZE_POINTER_COMPARE))
 	{
 	  op0 = save_expr (op0);
@@ -13861,6 +13854,8 @@ c_finish_omp_clauses (tree clauses, enum c_omp_region_type ort)
   tree simdlen = NULL_TREE, safelen = NULL_TREE;
   bool branch_seen = false;
   bool copyprivate_seen = false;
+  bool mergeable_seen = false;
+  tree *detach_seen = NULL;
   bool linear_variable_step_check = false;
   tree *nowait_clause = NULL;
   tree ordered_clause = NULL_TREE;
@@ -13986,7 +13981,9 @@ c_finish_omp_clauses (tree clauses, enum c_omp_region_type ort)
 	      size = size_binop (MINUS_EXPR, size, size_one_node);
 	      size = save_expr (size);
 	      tree index_type = build_index_type (size);
-	      tree atype = build_array_type (type, index_type);
+	      tree atype = build_array_type (TYPE_MAIN_VARIANT (type),
+					     index_type);
+	      atype = c_build_qualified_type (atype, TYPE_QUALS (type));
 	      tree ptype = build_pointer_type (type);
 	      if (TREE_CODE (TREE_TYPE (t)) == ARRAY_TYPE)
 		t = build_fold_addr_expr (t);
@@ -14942,6 +14939,21 @@ c_finish_omp_clauses (tree clauses, enum c_omp_region_type ort)
 	  pc = &OMP_CLAUSE_CHAIN (c);
 	  continue;
 
+	case OMP_CLAUSE_DETACH:
+	  t = OMP_CLAUSE_DECL (c);
+	  if (detach_seen)
+	    {
+	      error_at (OMP_CLAUSE_LOCATION (c),
+			"too many %qs clauses on a task construct",
+			"detach");
+	      remove = true;
+	      break;
+	    }
+	  detach_seen = pc;
+	  pc = &OMP_CLAUSE_CHAIN (c);
+	  c_mark_addressable (t);
+	  continue;
+
 	case OMP_CLAUSE_IF:
 	case OMP_CLAUSE_NUM_THREADS:
 	case OMP_CLAUSE_NUM_TEAMS:
@@ -14950,7 +14962,6 @@ c_finish_omp_clauses (tree clauses, enum c_omp_region_type ort)
 	case OMP_CLAUSE_UNTIED:
 	case OMP_CLAUSE_COLLAPSE:
 	case OMP_CLAUSE_FINAL:
-	case OMP_CLAUSE_MERGEABLE:
 	case OMP_CLAUSE_DEVICE:
 	case OMP_CLAUSE_DIST_SCHEDULE:
 	case OMP_CLAUSE_PARALLEL:
@@ -14984,6 +14995,11 @@ c_finish_omp_clauses (tree clauses, enum c_omp_region_type ort)
 	  pc = &OMP_CLAUSE_CHAIN (c);
 	  continue;
 
+	case OMP_CLAUSE_MERGEABLE:
+	  mergeable_seen = true;
+	  pc = &OMP_CLAUSE_CHAIN (c);
+	  continue;
+
 	case OMP_CLAUSE_NOGROUP:
 	  nogroup_seen = pc;
 	  pc = &OMP_CLAUSE_CHAIN (c);
@@ -15235,6 +15251,41 @@ c_finish_omp_clauses (tree clauses, enum c_omp_region_type ort)
       *nogroup_seen = OMP_CLAUSE_CHAIN (*nogroup_seen);
     }
 
+  if (detach_seen)
+    {
+      if (mergeable_seen)
+	{
+	  error_at (OMP_CLAUSE_LOCATION (*detach_seen),
+		    "%<detach%> clause must not be used together with "
+		    "%<mergeable%> clause");
+	  *detach_seen = OMP_CLAUSE_CHAIN (*detach_seen);
+	}
+      else
+	{
+	  tree detach_decl = OMP_CLAUSE_DECL (*detach_seen);
+
+	  for (pc = &clauses, c = clauses; c ; c = *pc)
+	    {
+	      bool remove = false;
+	      if ((OMP_CLAUSE_CODE (c) == OMP_CLAUSE_SHARED
+		   || OMP_CLAUSE_CODE (c) == OMP_CLAUSE_PRIVATE
+		   || OMP_CLAUSE_CODE (c) == OMP_CLAUSE_FIRSTPRIVATE
+		   || OMP_CLAUSE_CODE (c) == OMP_CLAUSE_LASTPRIVATE)
+		  && OMP_CLAUSE_DECL (c) == detach_decl)
+		{
+		  error_at (OMP_CLAUSE_LOCATION (c),
+			    "the event handle of a %<detach%> clause "
+			    "should not be in a data-sharing clause");
+		  remove = true;
+		}
+	      if (remove)
+		*pc = OMP_CLAUSE_CHAIN (c);
+	      else
+		pc = &OMP_CLAUSE_CHAIN (c);
+	    }
+	}
+    }
+
   bitmap_obstack_release (NULL);
   return clauses;
 }
diff --git a/gcc/c/config-lang.in b/gcc/c/config-lang.in
index 57578bb..b9cf5f3 100644
--- a/gcc/c/config-lang.in
+++ b/gcc/c/config-lang.in
@@ -1,5 +1,5 @@
 # Top level configure fragment for GNU C - C language.
-# Copyright (C) 1994-2020 Free Software Foundation, Inc.
+# Copyright (C) 1994-2021 Free Software Foundation, Inc.
 
 #This file is part of GCC.
 
diff --git a/gcc/c/gccspec.c b/gcc/c/gccspec.c
index 93136b4..db353a3 100644
--- a/gcc/c/gccspec.c
+++ b/gcc/c/gccspec.c
@@ -1,5 +1,5 @@
 /* Specific flags and argument handling of the C front-end.
-   Copyright (C) 1999-2020 Free Software Foundation, Inc.
+   Copyright (C) 1999-2021 Free Software Foundation, Inc.
 
 This file is part of GCC.
 
diff --git a/gcc/c/gimple-parser.c b/gcc/c/gimple-parser.c
index 5c0ed82..58b161b 100644
--- a/gcc/c/gimple-parser.c
+++ b/gcc/c/gimple-parser.c
@@ -1,5 +1,5 @@
 /* Parser for GIMPLE.
-   Copyright (C) 2016-2020 Free Software Foundation, Inc.
+   Copyright (C) 2016-2021 Free Software Foundation, Inc.
 
 This file is part of GCC.
 
@@ -616,8 +616,9 @@ c_parser_gimple_compound_statement (gimple_parser &parser, gimple_seq *seq)
 		      class loop *loop = alloc_loop ();
 		      loop->num = is_loop_header_of;
 		      loop->header = bb;
-		      vec_safe_grow_cleared (loops_for_fn (cfun)->larray,
-					     is_loop_header_of + 1, true);
+		      if (number_of_loops (cfun) <= (unsigned)is_loop_header_of)
+			vec_safe_grow_cleared (loops_for_fn (cfun)->larray,
+					       is_loop_header_of + 1, true);
 		      (*loops_for_fn (cfun)->larray)[is_loop_header_of] = loop;
 		      flow_loop_tree_node_add (loops_for_fn (cfun)->tree_root,
 					       loop);
@@ -1700,6 +1701,8 @@ c_parser_gimple_postfix_expression (gimple_parser &parser)
       expr.set_error ();
       break;
     }
+  if (expr.value == error_mark_node)
+    return expr;
   return c_parser_gimple_postfix_expression_after_primary
     (parser, EXPR_LOC_OR_LOC (expr.value, loc), expr);
 }
diff --git a/gcc/c/gimple-parser.h b/gcc/c/gimple-parser.h
index f3af1b0..6501bcf 100644
--- a/gcc/c/gimple-parser.h
+++ b/gcc/c/gimple-parser.h
@@ -1,5 +1,5 @@
 /* Declarations for the parser for GIMPLE.
-   Copyright (C) 2016-2020 Free Software Foundation, Inc.
+   Copyright (C) 2016-2021 Free Software Foundation, Inc.
 
 This file is part of GCC.