re PR target/80723 (FAIL gcc.target/i386/cadd.c scan assembler sbb)

	PR target/80723
	* config/i386/i386.c (ix86_rtx_cost) [case PLUS]: Ignore the
	cost of adding a carry flag for ADC instruction.
	[case MINUS]: Ignore the cost of subtracting a carry flag
	for SBB instruction.

From-SVN: r247991

gcc/ChangeLog

+2017-05-12  Uros Bizjak  <ubizjak@gmail.com>
+
+	PR target/80723
+	* config/i386/i386.c (ix86_rtx_cost) [case PLUS]: Ignore the
+	cost of adding a carry flag for ADC instruction.
+	[case MINUS]: Ignore the cost of subtracting a carry flag
+	for SBB instruction.
+
 2017-05-12  Steven Munroe  <munroesj@gcc.gnu.org>
 
 	* config.gcc (powerpc*-*-*): Add bmi2intrin.h, bmiintrin.h,
@@ -8,7 +16,7 @@
 
 2017-05-12  Jeff Law  <law@redhat.com>
 
-	* tree-vrp.c (vrp_dom_walker::before_dom_childern): Push unwinding
+	* tree-vrp.c (vrp_dom_walker::before_dom_children): Push unwinding
 	markers.
 
 2017-05-12  Peter Bergner  <bergner@vnet.ibm.com>

gcc/config/i386/i386.c

@@ -40913,9 +40913,16 @@ ix86_rtx_costs (rtx x, machine_mode mode, int outer_code_i, int opno,
 	    }
 	  else if (GET_CODE (XEXP (x, 0)) == PLUS)
 	    {
-	      *total = cost->lea;
-	      *total += rtx_cost (XEXP (XEXP (x, 0), 0), mode,
-				  outer_code, opno, speed);
+	      /* Add with carry, ignore the cost of adding a carry flag.  */
+	      if (ix86_carry_flag_operator (XEXP (XEXP (x, 0), 0), mode))
+		*total = cost->add;
+	      else
+		{
+		  *total = cost->lea;
+		  *total += rtx_cost (XEXP (XEXP (x, 0), 0), mode,
+				      outer_code, opno, speed);
+		}
+
 	      *total += rtx_cost (XEXP (XEXP (x, 0), 1), mode,
 				  outer_code, opno, speed);
 	      *total += rtx_cost (XEXP (x, 1), mode,
@@ -40926,6 +40933,20 @@ ix86_rtx_costs (rtx x, machine_mode mode, int outer_code_i, int opno,
       /* FALLTHRU */
 
     case MINUS:
+      /* Subtract with borrow, ignore the cost of subtracting a carry flag.  */
+      if (GET_MODE_CLASS (mode) == MODE_INT
+	  && GET_MODE_SIZE (mode) <= UNITS_PER_WORD
+	  && GET_CODE (XEXP (x, 0)) == MINUS
+	  && ix86_carry_flag_operator (XEXP (XEXP (x, 0), 1), mode))
+	{
+	  *total = cost->add;
+	  *total += rtx_cost (XEXP (XEXP (x, 0), 0), mode,
+			      outer_code, opno, speed);
+	  *total += rtx_cost (XEXP (x, 1), mode,
+			      outer_code, opno, speed);
+	  return true;
+	}
+
       if (SSE_FLOAT_MODE_P (mode) && TARGET_SSE_MATH)
 	{
 	  /* ??? SSE cost should be used here.  */