re PR tree-optimization/65204 (Aligned address optimization not detected)

2015-04-13  Richard Biener  <rguenther@suse.de>

	PR tree-optimization/65204
	* tree-ssa-ccp.c (evaluate_stmt): Always evaluate address
	takens for bit-CCP.

	* gcc.dg/tree-ssa/ssa-ccp-35.c: New testcase.

From-SVN: r222049

gcc/ChangeLog

@@ -1,3 +1,9 @@
+2015-04-13  Richard Biener  <rguenther@suse.de>
+
+	PR tree-optimization/65204
+	* tree-ssa-ccp.c (evaluate_stmt): Always evaluate address
+	takens for bit-CCP.
+
 2015-04-13  Richard Biener  <rguenther@suse.de>
 
 	PR target/65660

gcc/testsuite/ChangeLog

@@ -1,3 +1,8 @@
+2015-04-13  Richard Biener  <rguenther@suse.de>
+
+	PR tree-optimization/65204
+	* gcc.dg/tree-ssa/ssa-ccp-35.c: New testcase.
+
 2015-04-13  Terry Guo  <terry.guo@arm.com>
 
 	PR target/65710

gcc/testsuite/gcc.dg/tree-ssa/ssa-ccp-35.c

@@ -0,0 +1,15 @@
+/* { dg-do compile } */
+/* { dg-options "-O2 -fdump-tree-ccp1" } */
+
+typedef char char16[16] __attribute__ ((aligned (16)));
+char16 c16[4] __attribute__ ((aligned (4)));
+
+int f5 (int i)
+{
+  __SIZE_TYPE__ s = (__SIZE_TYPE__)&c16[i];
+  /* 0 */
+  return 3 & s;
+}
+
+/* { dg-final { scan-tree-dump "return 0;" "ccp1" } } */
+/* { dg-final { cleanup-tree-dump "ccp1" } } */

gcc/tree-ssa-ccp.c

@@ -1748,7 +1748,9 @@ evaluate_stmt (gimple stmt)
 
   /* Resort to simplification for bitwise tracking.  */
   if (flag_tree_bit_ccp
-      && (likelyvalue == CONSTANT || is_gimple_call (stmt))
+      && (likelyvalue == CONSTANT || is_gimple_call (stmt)
+	  || (gimple_assign_single_p (stmt)
+	      && gimple_assign_rhs_code (stmt) == ADDR_EXPR))
       && !is_constant)
     {
       enum gimple_code code = gimple_code (stmt);