re PR tree-optimization/53085 (writes to volatile struct members is missing)

2012-04-24  Richard Guenther  <rguenther@suse.de>

	PR tree-optimization/53085
	* tree-ssa-pre.c (eliminate): Do not eliminate volatile redundant
	stores.

	* g++.dg/torture/pr53085.C: New testcase.

From-SVN: r186764

gcc/ChangeLog

 2012-04-24  Richard Guenther  <rguenther@suse.de>
 
+	PR tree-optimization/53085
+	* tree-ssa-pre.c (eliminate): Do not eliminate volatile redundant
+	stores.
+
+2012-04-24  Richard Guenther  <rguenther@suse.de>
+
 	* tree-if-conv.c (main_tree_if_conversion): Move bb under
 	ENABLE_CHECKING.
 

gcc/testsuite/ChangeLog

+2012-04-24  Richard Guenther  <rguenther@suse.de>
+
+	PR tree-optimization/53085
+	* g++.dg/torture/pr53085.C: New testcase.
+
 2012-04-24  Andrew Pinski  <apinski@cavium.com>
 
 	PR tree-opt/33512

gcc/testsuite/g++.dg/torture/pr53085.C

+// { dg-do compile }
+// { dg-skip-if "" { *-*-* } { "-fno-fat-lto-objects" } { "" } }
+// { dg-options "-fdump-tree-optimized" }
+
+class aa{
+    void f();
+private:
+    volatile int a;
+};
+
+void aa::f(){
+    a=1;
+    a=1;
+}
+
+// { dg-final { scan-tree-dump-times "a ={v} 1;" 2 "optimized" } }
+// { dg-final { cleanup-tree-dump "optimized" } }

gcc/tree-ssa-pre.c

@@ -4409,6 +4409,7 @@ eliminate (void)
 	     has the same value number as its rhs.  If so, the store is
 	     dead.  */
 	  else if (gimple_assign_single_p (stmt)
+		   && !gimple_has_volatile_ops (stmt)
 		   && !is_gimple_reg (gimple_assign_lhs (stmt))
 		   && (TREE_CODE (rhs) == SSA_NAME
 		       || is_gimple_min_invariant (rhs)))