mips.c (mips_add_offset): Use gen_int_mode for CONST_HIGH_PART result.

* config/mips/mips.c (mips_add_offset): Use gen_int_mode for
CONST_HIGH_PART result.

From-SVN: r146995

gcc/ChangeLog

+2009-04-29  James E. Wilson  <wilson@codesourcery.com>
+
+	* config/mips/mips.c (mips_add_offset): Use gen_int_mode for
+	CONST_HIGH_PART result.
+
 2009-04-29  Anatoly Sokolov  <aesok@post.ru>
 
 	* config/avr/avr.c (initial_elimination_offset): Rename to

gcc/config/mips/mips.c

@@ -2703,8 +2703,10 @@ mips_add_offset (rtx temp, rtx reg, HOST_WIDE_INT offset)
 	}
       else
 	{
-	  /* Leave OFFSET as a 16-bit offset and put the excess in HIGH.  */
-	  high = GEN_INT (CONST_HIGH_PART (offset));
+	  /* Leave OFFSET as a 16-bit offset and put the excess in HIGH.
+	     The addition inside the macro CONST_HIGH_PART may cause an
+	     overflow, so we need to force a sign-extension check.  */
+	  high = gen_int_mode (CONST_HIGH_PART (offset), Pmode);
 	  offset = CONST_LOW_PART (offset);
 	}
       high = mips_force_temporary (temp, high);