OpenMP (C only): For 'omp allocate', really walk tree for 'alloctor' check

Walk expression tree of the 'allocator' clause of 'omp allocate' to
detect more cases where the allocator expression depends on code between
a variable declaration and its associated '#pragma omp allocate'. It also
contains the fix for the 'allocator((omp_allocator_handle_t)-1)' ICE, also
tested for in previous commit.

The changes of this commit were supposed to be part of
  r14-3863-g35f498d8dfc8e579eaba2ff2d2b96769c632fd58
  OpenMP (C only): omp allocate - extend parsing support, improve diagnostic
which also contains the associated testcase changes but were left out (oops!).

gcc/c/ChangeLog:

	* c-parser.cc (struct c_omp_loc_tree): New.
	(c_check_omp_allocate_allocator_r): New; checking moved from ...
	(c_parser_omp_allocate): ... here. Call it via walk_tree. Avoid
	ICE with tree_to_shwi for invalid too-large value.

1 files changed, 61 insertions, 41 deletions

diff --git a/gcc/c/c-parser.cc b/gcc/c/c-parser.cc
index 643ec02..b9a1b75 100644
--- a/gcc/c/c-parser.cc
+++ b/gcc/c/c-parser.cc
@@ -19343,6 +19343,61 @@ c_parser_oacc_wait (location_t loc, c_parser *parser, char *p_name)
   return stmt;
 }
 
+struct c_omp_loc_tree
+{
+  location_t loc;
+  tree var;
+};
+
+/* Check whether the expression used in the allocator clause is declared or
+   modified between the variable declaration and its allocate directive.  */
+static tree
+c_check_omp_allocate_allocator_r (tree *tp, int *, void *data)
+{
+  tree var = ((struct c_omp_loc_tree *) data)->var;
+  location_t loc = ((struct c_omp_loc_tree *) data)->loc;
+  if (TREE_CODE (*tp) == VAR_DECL && c_check_in_current_scope (*tp))
+    {
+      if (linemap_location_before_p (line_table, DECL_SOURCE_LOCATION (var),
+				     DECL_SOURCE_LOCATION (*tp)))
+	{
+	  error_at (loc, "variable %qD used in the %<allocator%> clause must "
+			 "be declared before %qD", *tp, var);
+	  inform (DECL_SOURCE_LOCATION (*tp), "declared here");
+	  inform (DECL_SOURCE_LOCATION (var),
+		  "to be allocated variable declared here");
+	  return *tp;
+	}
+      else
+	{
+	  gcc_assert (cur_stmt_list
+		      && TREE_CODE (cur_stmt_list) == STATEMENT_LIST);
+
+	  tree_stmt_iterator l = tsi_last (cur_stmt_list);
+	  while (!tsi_end_p (l))
+	    {
+	      if (linemap_location_before_p (line_table, EXPR_LOCATION (*l),
+					     DECL_SOURCE_LOCATION (var)))
+		  break;
+	      if (TREE_CODE (*l) == MODIFY_EXPR
+		  && TREE_OPERAND (*l, 0) == *tp)
+		{
+		  error_at (loc,
+			    "variable %qD used in the %<allocator%> clause "
+			    "must not be modified between declaration of %qD "
+			    "and its %<allocate%> directive", *tp, var);
+		  inform (EXPR_LOCATION (*l), "modified here");
+		  inform (DECL_SOURCE_LOCATION (var),
+			  "to be allocated variable declared here");
+		  return *tp;
+		}
+	      --l;
+	    }
+	}
+    }
+  return NULL_TREE;
+}
+
 /* OpenMP 5.x:
    # pragma omp allocate (list)  clauses
 
@@ -19465,8 +19520,8 @@ c_parser_omp_allocate (c_parser *parser)
 	    error_at (loc, "%<allocator%> clause required for "
 			   "static variable %qD", var);
 	  else if (allocator
-		   && (tree_int_cst_sgn (allocator) != 1
-		       || tree_to_shwi (allocator) > 8))
+		   && (wi::to_widest (allocator) < 1
+		       || wi::to_widest (allocator) > 8))
 	    /* 8 = largest predefined memory allocator. */
 	    error_at (allocator_loc,
 		      "%<allocator%> clause requires a predefined allocator as "
@@ -19477,46 +19532,11 @@ c_parser_omp_allocate (c_parser *parser)
 		      "%qD not yet supported", var);
 	  continue;
 	}
-      if (allocator
-	  && TREE_CODE (allocator) == VAR_DECL
-	  && c_check_in_current_scope (var))
+      if (allocator)
 	{
-	  if (linemap_location_before_p (line_table, DECL_SOURCE_LOCATION (var),
-					 DECL_SOURCE_LOCATION (allocator)))
-	    {
-	      error_at (OMP_CLAUSE_LOCATION (nl),
-			"allocator variable %qD must be declared before %qD",
-			allocator, var);
-	      inform (DECL_SOURCE_LOCATION (allocator),
-		      "allocator declared here");
-	      inform (DECL_SOURCE_LOCATION (var), "declared here");
-	    }
-	  else
-	   {
-	     gcc_assert (cur_stmt_list
-			 && TREE_CODE (cur_stmt_list) == STATEMENT_LIST);
-	     tree_stmt_iterator l = tsi_last (cur_stmt_list);
-	     while (!tsi_end_p (l))
-	       {
-		 if (linemap_location_before_p (line_table, EXPR_LOCATION (*l),
-						DECL_SOURCE_LOCATION (var)))
-		   break;
-		 if (TREE_CODE (*l) == MODIFY_EXPR
-		     && TREE_OPERAND (*l, 0) == allocator)
-		   {
-		     error_at (EXPR_LOCATION (*l),
-			       "allocator variable %qD, used in the "
-			       "%<allocate%> directive for %qD, must not be "
-			       "modified between declaration of %qD and its "
-			       "%<allocate%> directive",
-			       allocator, var, var);
-		     inform (DECL_SOURCE_LOCATION (var), "declared here");
-		     inform (OMP_CLAUSE_LOCATION (nl), "used here");
-		     break;
-		  }
-		--l;
-	     }
-	   }
+	  struct c_omp_loc_tree data
+	    = {EXPR_LOC_OR_LOC (allocator, OMP_CLAUSE_LOCATION (nl)), var};
+	  walk_tree (&allocator, c_check_omp_allocate_allocator_r, &data, NULL);
 	}
       DECL_ATTRIBUTES (var) = tree_cons (get_identifier ("omp allocate"),
 					 build_tree_list (allocator, alignment),