[backport from gcc-4.7/trunk via ARM/embedded-4_6-branch <mikpe@it.uu.se>]

From: Richard Sandiford <richard dot sandiford at linaro dot org>
Subject: Use gen_int_mode in expand_builtin_memset_args
Date: Mon, 28 Mar 2011 16:47:35 +0100
List-Archive: <http://gcc.gnu.org/ml/gcc-patches/>

This patch fixes a case where expand_builtin_memset_args was creating
a zero- rather than sign-extended character-sized CONST_INT.  The problem
showed up on s390, where a character was being passed as (const_int 171)
rather than (const_int -85).

Tested on x86_64-linux-gnu.  Andreas also confirms that it fixes
the s390 failure.  OK to install?

Richard

gcc/

2011-09-19  chengbin  <bin.cheng@arm.com>

	Backport r171632 from mainline
	2011-03-28  Richard Sandiford  <richard.sandiford@linaro.org>

	* builtins.c (expand_builtin_memset_args): Use gen_int_mode
	instead of GEN_INT.

--- gcc-4.6.2/gcc/builtins.c.~1~	2011-10-06 21:57:52.000000000 +0200
+++ gcc-4.6.2/gcc/builtins.c	2011-12-17 19:11:53.000000000 +0100
@@ -3972,6 +3972,7 @@ expand_builtin_memset_args (tree dest, t
 {
   tree fndecl, fn;
   enum built_in_function fcode;
+  enum machine_mode val_mode;
   char c;
   unsigned int dest_align;
   rtx dest_mem, dest_addr, len_rtx;
@@ -4006,14 +4007,14 @@ expand_builtin_memset_args (tree dest, t
 
   len_rtx = expand_normal (len);
   dest_mem = get_memory_rtx (dest, len);
+  val_mode = TYPE_MODE (unsigned_char_type_node);
 
   if (TREE_CODE (val) != INTEGER_CST)
     {
       rtx val_rtx;
 
       val_rtx = expand_normal (val);
-      val_rtx = convert_to_mode (TYPE_MODE (unsigned_char_type_node),
-				 val_rtx, 0);
+      val_rtx = convert_to_mode (val_mode, val_rtx, 0);
 
       /* Assume that we can memset by pieces if we can store
        * the coefficients by pieces (in the required modes).
@@ -4024,8 +4025,7 @@ expand_builtin_memset_args (tree dest, t
 				  builtin_memset_read_str, &c, dest_align,
 				  true))
 	{
-	  val_rtx = force_reg (TYPE_MODE (unsigned_char_type_node),
-			       val_rtx);
+	  val_rtx = force_reg (val_mode, val_rtx);
 	  store_by_pieces (dest_mem, tree_low_cst (len, 1),
 			   builtin_memset_gen_str, val_rtx, dest_align,
 			   true, 0);
@@ -4051,7 +4051,8 @@ expand_builtin_memset_args (tree dest, t
 				  true))
 	store_by_pieces (dest_mem, tree_low_cst (len, 1),
 			 builtin_memset_read_str, &c, dest_align, true, 0);
-      else if (!set_storage_via_setmem (dest_mem, len_rtx, GEN_INT (c),
+      else if (!set_storage_via_setmem (dest_mem, len_rtx,
+					gen_int_mode (c, val_mode),
 					dest_align, expected_align,
 					expected_size))
 	goto do_libcall;