machmode.h (GET_MODE_UNIT_PRECISION): New macro.

gcc/
	* machmode.h (GET_MODE_UNIT_PRECISION): New macro.
	* simplify-rtx.c (simplify_truncation): New function,
	extracted from simplify_subreg and (in small part) from
	simplify_unary_operation_1.
	(simplify_unary_operation_1) <TRUNCATE>: Use it.  Remove sign bit
	test for !TRULY_NOOP_TRUNCATION_MODES_P.
	(simplify_subreg): Use simplify_truncate for lowpart subregs
	where both the inner and outer modes are scalar integers.
	* config/mips/mips.c (mips_truncated_op_cost): New function.
	(mips_rtx_costs): Adjust test for BADDU.
	* config/mips/mips.md (*baddu_di<mode>): Push truncates to operands.

From-SVN: r192186

gcc/ChangeLog

+2012-10-07  Richard Sandiford  <rdsandiford@googlemail.com>
+
+	* machmode.h (GET_MODE_UNIT_PRECISION): New macro.
+	* simplify-rtx.c (simplify_truncation): New function,
+	extracted from simplify_subreg and (in small part) from
+	simplify_unary_operation_1.
+	(simplify_unary_operation_1) <TRUNCATE>: Use it.  Remove sign bit
+	test for !TRULY_NOOP_TRUNCATION_MODES_P.
+	(simplify_subreg): Use simplify_truncate for lowpart subregs
+	where both the inner and outer modes are scalar integers.
+	* config/mips/mips.c (mips_truncated_op_cost): New function.
+	(mips_rtx_costs): Adjust test for BADDU.
+	* config/mips/mips.md (*baddu_di<mode>): Push truncates to operands.
+
 2012-10-07  Jan Hubicka  <jh@suse.cz>
 
 	* ipa-inline-analysis.c (do_estimate_edge_time): Return actual

gcc/config/mips/mips.c

@@ -3557,6 +3557,17 @@ mips_set_reg_reg_cost (enum machine_mode mode)
     }
 }
 
+/* Return the cost of an operand X that can be trucated for free.
+   SPEED says whether we're optimizing for size or speed.  */
+
+static int
+mips_truncated_op_cost (rtx x, bool speed)
+{
+  if (GET_CODE (x) == TRUNCATE)
+    x = XEXP (x, 0);
+  return set_src_cost (x, speed);
+}
+
 /* Implement TARGET_RTX_COSTS.  */
 
 static bool
@@ -3937,12 +3948,13 @@ mips_rtx_costs (rtx x, int code, int outer_code, int opno ATTRIBUTE_UNUSED,
     case ZERO_EXTEND:
       if (outer_code == SET
 	  && ISA_HAS_BADDU
-	  && (GET_CODE (XEXP (x, 0)) == TRUNCATE
-	      || GET_CODE (XEXP (x, 0)) == SUBREG)
 	  && GET_MODE (XEXP (x, 0)) == QImode
-	  && GET_CODE (XEXP (XEXP (x, 0), 0)) == PLUS)
+	  && GET_CODE (XEXP (x, 0)) == PLUS)
 	{
-	  *total = set_src_cost (XEXP (XEXP (x, 0), 0), speed);
+	  rtx plus = XEXP (x, 0);
+	  *total = (COSTS_N_INSNS (1)
+		    + mips_truncated_op_cost (XEXP (plus, 0), speed)
+		    + mips_truncated_op_cost (XEXP (plus, 1), speed));
 	  return true;
 	}
       *total = mips_zero_extend_cost (mode, XEXP (x, 0));

gcc/config/mips/mips.md

@@ -1306,9 +1306,8 @@
 (define_insn "*baddu_di<mode>"
   [(set (match_operand:GPR 0 "register_operand" "=d")
         (zero_extend:GPR
-	 (truncate:QI
-	  (plus:DI (match_operand:DI 1 "register_operand" "d")
-		   (match_operand:DI 2 "register_operand" "d")))))]
+	 (plus:QI (truncate:QI (match_operand:DI 1 "register_operand" "d"))
+		  (truncate:QI (match_operand:DI 2 "register_operand" "d")))))]
   "ISA_HAS_BADDU && TARGET_64BIT"
   "baddu\\t%0,%1,%2"
   [(set_attr "alu_type" "add")])

gcc/machmode.h

@@ -217,6 +217,11 @@ extern const unsigned char mode_inner[NUM_MACHINE_MODES];
 #define GET_MODE_UNIT_BITSIZE(MODE) \
   ((unsigned short) (GET_MODE_UNIT_SIZE (MODE) * BITS_PER_UNIT))
 
+#define GET_MODE_UNIT_PRECISION(MODE)		\
+  (GET_MODE_INNER (MODE) == VOIDmode		\
+   ? GET_MODE_PRECISION (MODE)			\
+   : GET_MODE_PRECISION (GET_MODE_INNER (MODE)))
+
 /* Get the number of units in the object.  */
 
 extern const unsigned char mode_nunits[NUM_MACHINE_MODES];