expr.c (expand_expr_real_1): Only use BLKmode for volatile accesses which are…

expr.c (expand_expr_real_1): Only use BLKmode for volatile accesses which are not naturally aligned.

	* expr.c (expand_expr_real_1): Only use BLKmode for volatile
	accesses which are not naturally aligned.

From-SVN: r171347

gcc/ChangeLog

+2011-03-23  Julian Brown  <julian@codesourcery.com>
+
+	* expr.c (expand_expr_real_1): Only use BLKmode for volatile
+	accesses which are not naturally aligned.
+
 2011-03-23  Richard Sandiford  <richard.sandiford@linaro.org>
 
 	PR target/47553

gcc/expr.c

@@ -9147,8 +9147,11 @@ expand_expr_real_1 (tree exp, rtx target, enum machine_mode tmode,
 		&& modifier != EXPAND_CONST_ADDRESS
 		&& modifier != EXPAND_INITIALIZER)
 	    /* If the field is volatile, we always want an aligned
-	       access.  */
-	    || (volatilep && flag_strict_volatile_bitfields > 0)
+	       access.  Only do this if the access is not already naturally
+	       aligned, otherwise "normal" (non-bitfield) volatile fields
+	       become non-addressable.  */
+	    || (volatilep && flag_strict_volatile_bitfields > 0
+		&& (bitpos % GET_MODE_ALIGNMENT (mode) != 0))
 	    /* If the field isn't aligned enough to fetch as a memref,
 	       fetch it as a bit field.  */
 	    || (mode1 != BLKmode