Re: [Patch, C++] Add C++ FE support for #pragma ivdep

[Tobias Burnus <burnus at net-b dot de>]

*PING* - with a slightly updated patch attached. Changes: New test case 
for an error message plus matching the wording to the C version.

Tobias

On October 10, 2013, Tobias Burnus wrote:
> This patch depends on the middle-end / C FE patch: 
> http://gcc.gnu.org/ml/gcc-patches/2013-10/msg00655.html
>
> It adds parsing support for #pragma ivdep and annotates the condition 
> of C-like for loops such that one can later set the vectorization safe 
> length (loop->safelen) to INT_MAX.  I considered to add the annotation 
> also to C++11's range-based loops, but as those are unlikely to 
> vectorize, I didn't do so. (If one does, one might end up having a 
> CLEANUP_POINT_EXPR around the annotate; that implies that the annotate 
> internal function is not the direct predecessor of the GIMPLE_COND.)
>
> Another question is how much diagnostic one gives, e.g. when there is 
> no condition: Should there be an error, a warning or should the pragma 
> then silently ignored?
>
> Build and regtested on x86-64-gnu-linux.
> OK for the trunk?
>
> Tobias

2013-08-22  Tobias Burnus  <burnus@net-b.de>

	PR other/33426
	* parser.c (cp_parser_iteration_statement,
	cp_parser_for, cp_parser_c_for, cp_parser_pragma): Handle
	IVDEP pragma.

	* g++.dg/parse/ivdep.C: New.
	* g++.dg/vect/pr33426-ivdep.cc: New.

diff --git a/gcc/cp/parser.c b/gcc/cp/parser.c
index 10a7b96..46f6d18 100644
--- a/gcc/cp/parser.c
+++ b/gcc/cp/parser.c
@@ -1970,13 +1970,13 @@ static tree cp_parser_selection_statement
 static tree cp_parser_condition
   (cp_parser *);
 static tree cp_parser_iteration_statement
-  (cp_parser *);
+  (cp_parser *, bool);
 static bool cp_parser_for_init_statement
   (cp_parser *, tree *decl);
 static tree cp_parser_for
-  (cp_parser *);
+  (cp_parser *, bool);
 static tree cp_parser_c_for
-  (cp_parser *, tree, tree);
+  (cp_parser *, tree, tree, bool);
 static tree cp_parser_range_for
   (cp_parser *, tree, tree, tree);
 static void do_range_for_auto_deduction
@@ -9231,7 +9231,7 @@ cp_parser_statement (cp_parser* parser, tree in_statement_expr,
 	case RID_WHILE:
 	case RID_DO:
 	case RID_FOR:
-	  statement = cp_parser_iteration_statement (parser);
+	  statement = cp_parser_iteration_statement (parser, false);
 	  break;
 
 	case RID_BREAK:
@@ -9892,7 +9892,7 @@ cp_parser_condition (cp_parser* parser)
    not included. */
 
 static tree
-cp_parser_for (cp_parser *parser)
+cp_parser_for (cp_parser *parser, bool ivdep)
 {
   tree init, scope, decl;
   bool is_range_for;
@@ -9906,11 +9906,11 @@ cp_parser_for (cp_parser *parser)
   if (is_range_for)
     return cp_parser_range_for (parser, scope, init, decl);
   else
-    return cp_parser_c_for (parser, scope, init);
+    return cp_parser_c_for (parser, scope, init, ivdep);
 }
 
 static tree
-cp_parser_c_for (cp_parser *parser, tree scope, tree init)
+cp_parser_c_for (cp_parser *parser, tree scope, tree init, bool ivdep)
 {
   /* Normal for loop */
   tree condition = NULL_TREE;
@@ -9924,7 +9924,20 @@ cp_parser_c_for (cp_parser *parser, tree scope, tree init)
 
   /* If there's a condition, process it.  */
   if (cp_lexer_next_token_is_not (parser->lexer, CPP_SEMICOLON))
-    condition = cp_parser_condition (parser);
+    {
+      condition = cp_parser_condition (parser);
+      if (ivdep)
+	{
+	  condition = build1 (ANNOTATE_EXPR, TREE_TYPE (condition), condition);
+	  SET_ANNOTATE_EXPR_ID (condition, annot_expr_ivdep_kind);
+	}
+    }
+  else if (ivdep)
+    {
+      cp_parser_error (parser, "missing loop condition in loop with "
+		       "%<GCC ivdep%> pragma");
+      condition = error_mark_node;
+    }
   finish_for_cond (condition, stmt);
   /* Look for the `;'.  */
   cp_parser_require (parser, CPP_SEMICOLON, RT_SEMICOLON);
@@ -10287,7 +10300,7 @@ cp_parser_range_for_member_function (tree range, tree identifier)
    Returns the new WHILE_STMT, DO_STMT, FOR_STMT or RANGE_FOR_STMT.  */
 
 static tree
-cp_parser_iteration_statement (cp_parser* parser)
+cp_parser_iteration_statement (cp_parser* parser, bool ivdep)
 {
   cp_token *token;
   enum rid keyword;
@@ -10360,7 +10373,7 @@ cp_parser_iteration_statement (cp_parser* parser)
 	/* Look for the `('.  */
 	cp_parser_require (parser, CPP_OPEN_PAREN, RT_OPEN_PAREN);
 
-	statement = cp_parser_for (parser);
+	statement = cp_parser_for (parser, ivdep);
 
 	/* Look for the `)'.  */
 	cp_parser_require (parser, CPP_CLOSE_PAREN, RT_CLOSE_PAREN);
@@ -30906,6 +30919,20 @@ cp_parser_pragma (cp_parser *parser, enum pragma_context context)
 		"%<#pragma omp sections%> construct");
       break;
 
+    case PRAGMA_IVDEP:
+      {
+	cp_parser_skip_to_pragma_eol (parser, pragma_tok);
+	cp_token *tok;
+	tok = cp_lexer_peek_token (the_parser->lexer);
+	if (tok->type != CPP_KEYWORD || tok->keyword != RID_FOR)
+	  {
+	    cp_parser_error (parser, "for statement expected");
+	    return false;
+	  }
+	cp_parser_iteration_statement (parser, true);
+	return true;
+      }
+
     default:
       gcc_assert (id >= PRAGMA_FIRST_EXTERNAL);
       c_invoke_pragma_handler (id);
diff --git a/gcc/testsuite/g++.dg/parse/ivdep.C b/gcc/testsuite/g++.dg/parse/ivdep.C
new file mode 100644
index 0000000..23d51de
--- /dev/null
+++ b/gcc/testsuite/g++.dg/parse/ivdep.C
@@ -0,0 +1,11 @@
+/* { dg-do compile } */
+
+/* PR other/33426 */
+
+void foo(int n, int *a, int *b, int *c, int *d, int *e) {
+  int i, j;
+#pragma GCC ivdep
+  for (i = 0; ; ++i) { /* { dg-error "missing loop condition in loop with 'GCC ivdep' pragma before ';' token" } */
+    a[i] = b[i] + c[i];
+  }
+}
diff --git a/gcc/testsuite/g++.dg/vect/pr33426-ivdep.cc b/gcc/testsuite/g++.dg/vect/pr33426-ivdep.cc
new file mode 100644
index 0000000..7f867c6
--- /dev/null
+++ b/gcc/testsuite/g++.dg/vect/pr33426-ivdep.cc
@@ -0,0 +1,19 @@
+/* { dg-do compile } */
+/* { dg-require-effective-target vect_float } */
+/* { dg-options "-O3 -fopt-info-vec-optimized" } */
+
+/* PR other/33426 */
+/* Testing whether #pragma ivdep is working.  */
+
+void foo(int n, int *a, int *b, int *c, int *d, int *e) {
+  int i;
+#pragma GCC ivdep
+  for (i = 0; i < n; ++i) {
+    a[i] = b[i] + c[i];
+  }
+}
+
+/* { dg-message "loop vectorized" "" { target *-*-* } 0 } */
+/* { dg-bogus "version" "" { target *-*-* } 0 } */
+/* { dg-bogus "alias" "" { target *-*-* } 0 } */
+/* { dg-final { cleanup-tree-dump "vect" } } */