re PR c/53937 (Pack'ing struct causes gcc to not recognize that an field's address is aligned)

2012-07-13  Richard Guenther  <rguenther@suse.de>

	PR middle-end/53937
	* builtins.c (get_pointer_alignment_1): Handle constant
	pointers.

From-SVN: r189458

gcc/ChangeLog

+2012-07-13  Richard Guenther  <rguenther@suse.de>
+
+	PR middle-end/53937
+	* builtins.c (get_pointer_alignment_1): Handle constant
+	pointers.
+
 2012-07-13  Richard Sandiford  <rdsandiford@googlemail.com>
 	    Steven Bosscher  <steven@gcc.gnu.org>
 	    Bernd Schmidt  <bernds@codesourcery.com>

gcc/builtins.c

@@ -536,6 +536,13 @@ get_pointer_alignment_1 (tree exp, unsigned int *alignp,
 	  return false;
 	}
     }
+  else if (TREE_CODE (exp) == INTEGER_CST)
+    {
+      *alignp = BIGGEST_ALIGNMENT;
+      *bitposp = ((TREE_INT_CST_LOW (exp) * BITS_PER_UNIT)
+		  & (BIGGEST_ALIGNMENT - 1));
+      return true;
+    }
 
   *bitposp = 0;
   *alignp = BITS_PER_UNIT;