re PR tree-optimization/60577 (inefficient FDO instrumentation code)

2014-03-21  Richard Biener  <rguenther@suse.de>

	PR tree-optimization/60577
	* tree-core.h (struct tree_base): Document nothrow_flag use
	in VAR_DECL_NONALIASED.
	* tree.h (VAR_DECL_NONALIASED): New.
	(may_be_aliased): Adjust.
	* coverage.c (build_var): Set VAR_DECL_NONALIASED.

	* gcc.dg/tree-ssa/ssa-lim-11.c: New testcase.

From-SVN: r208746

gcc/ChangeLog

+2014-03-21  Richard Biener  <rguenther@suse.de>
+
+	PR tree-optimization/60577
+	* tree-core.h (struct tree_base): Document nothrow_flag use
+	in VAR_DECL_NONALIASED.
+	* tree.h (VAR_DECL_NONALIASED): New.
+	(may_be_aliased): Adjust.
+	* coverage.c (build_var): Set VAR_DECL_NONALIASED.
+
 2014-03-20  Eric Botcazou  <ebotcazou@adacore.com>
 
 	* expr.c (expand_expr_real_1): Remove outdated comment.

gcc/coverage.c

@@ -721,6 +721,7 @@ build_var (tree fn_decl, tree type, int counter)
   DECL_NAME (var) = get_identifier (buf);
   TREE_STATIC (var) = 1;
   TREE_ADDRESSABLE (var) = 1;
+  DECL_NONALIASED (var) = 1;
   DECL_ALIGN (var) = TYPE_ALIGN (type);
 
   return var;

gcc/testsuite/ChangeLog

+2014-03-21  Richard Biener  <rguenther@suse.de>
+
+	PR tree-optimization/60577
+	* gcc.dg/tree-ssa/ssa-lim-11.c: New testcase.
+
 2014-03-21  Tobias Burnus  <burnus@net-b.de>
 
 	PR fortran/60599

gcc/testsuite/gcc.dg/tree-ssa/ssa-lim-11.c

+/* { dg-do compile } */
+/* { dg-options "-O -fprofile-arcs -fdump-tree-lim1-details" } */
+
+struct thread_param
+{
+  long* buf;
+  long iterations;
+  long accesses;
+} param;
+
+void access_buf(struct thread_param* p)
+{
+  long i,j;
+  long iterations = p->iterations;
+  long accesses = p->accesses;
+  for (i=0; i<iterations; i++)
+    {
+      long* pbuf = p->buf;
+      for (j=0; j<accesses; j++)
+	pbuf[j] += 1;
+    }
+}
+
+/* { dg-final { scan-tree-dump-times "Executing store motion of __gcov0.access_buf\\\[\[01\]\\\] from loop 1" 2 "lim1" } } */
+/* { dg-final { cleanup-tree-dump "lim1" } } */

gcc/tree-core.h

@@ -987,6 +987,9 @@ struct GTY(()) tree_base {
        SSA_NAME_IN_FREELIST in
           SSA_NAME
 
+       VAR_DECL_NONALIASED in
+	  VAR_DECL
+
    deprecated_flag:
 
        TREE_DEPRECATED in

gcc/tree.h

@@ -2441,6 +2441,10 @@ extern void decl_fini_priority_insert (tree, priority_type);
 #define DECL_NONLOCAL_FRAME(NODE)  \
   (VAR_DECL_CHECK (NODE)->base.default_def_flag)
 
+/* In a VAR_DECL, nonzero if this variable is not aliased by any pointer.  */
+#define DECL_NONALIASED(NODE) \
+  (VAR_DECL_CHECK (NODE)->base.nothrow_flag)
+
 /* This field is used to reference anything in decl.result and is meant only
    for use by the garbage collector.  */
 #define DECL_RESULT_FLD(NODE) \
@@ -4462,12 +4466,14 @@ static inline bool
 may_be_aliased (const_tree var)
 {
   return (TREE_CODE (var) != CONST_DECL
-	  && !((TREE_STATIC (var) || TREE_PUBLIC (var) || DECL_EXTERNAL (var))
-	       && TREE_READONLY (var)
-	       && !TYPE_NEEDS_CONSTRUCTING (TREE_TYPE (var)))
 	  && (TREE_PUBLIC (var)
 	      || DECL_EXTERNAL (var)
-	      || TREE_ADDRESSABLE (var)));
+	      || TREE_ADDRESSABLE (var))
+	  && !((TREE_STATIC (var) || TREE_PUBLIC (var) || DECL_EXTERNAL (var))
+	       && ((TREE_READONLY (var)
+		    && !TYPE_NEEDS_CONSTRUCTING (TREE_TYPE (var)))
+		   || (TREE_CODE (var) == VAR_DECL
+		       && DECL_NONALIASED (var)))));
 }
 
 /* Return pointer to optimization flags of FNDECL.  */