re PR target/77613 (Powerpc64le: redundant swaps in autovectorised loop)

[gcc]

2016-09-16  Bill Schmidt  <wschmidt@linux.vnet.ibm.com>

	PR target/77613
	* config/rs6000/rs6000.c (rtx_is_swappable_p): Add support for
	splat with truncate.

[gcc/testsuite]

2016-09-16  Bill Schmidt  <wschmidt@linux.vnet.ibm.com>

	PR target/77613
	* gcc.target/powerpc/swaps-p8-25.c: New.

From-SVN: r240199

gcc/ChangeLog

+2016-09-16  Bill Schmidt  <wschmidt@linux.vnet.ibm.com>
+
+	PR target/77613
+	* config/rs6000/rs6000.c (rtx_is_swappable_p): Add support for
+	splat with truncate.
+
 2016-09-16  Jason Merrill  <jason@redhat.com>
 
 	* hwint.h (least_bit_hwi, pow2_or_zerop, pow2p_hwi, ctz_or_zero):

gcc/config/rs6000/rs6000.c

@@ -39101,10 +39101,15 @@ rtx_is_swappable_p (rtx op, unsigned int *special)
 	 handling.  */
       if (GET_CODE (XEXP (op, 0)) == CONST_INT)
 	return 1;
-      else if (GET_CODE (XEXP (op, 0)) == REG
+      else if (REG_P (XEXP (op, 0))
 	       && GET_MODE_INNER (GET_MODE (op)) == GET_MODE (XEXP (op, 0)))
 	/* This catches V2DF and V2DI splat, at a minimum.  */
 	return 1;
+      else if (GET_CODE (XEXP (op, 0)) == TRUNCATE
+	       && REG_P (XEXP (XEXP (op, 0), 0))
+	       && GET_MODE_INNER (GET_MODE (op)) == GET_MODE (XEXP (op, 0)))
+	/* This catches splat of a truncated value.  */
+	return 1;
       else if (GET_CODE (XEXP (op, 0)) == VEC_SELECT)
 	/* If the duplicated item is from a select, defer to the select
 	   processing to see if we can change the lane for the splat.  */

gcc/testsuite/ChangeLog

+2016-09-16  Bill Schmidt  <wschmidt@linux.vnet.ibm.com>
+
+	PR target/77613
+	* gcc.target/powerpc/swaps-p8-25.c: New.
+
 2016-09-16  Jakub Jelinek  <jakub@redhat.com>
 
 	PR c++/77482

gcc/testsuite/gcc.target/powerpc/swaps-p8-25.c

+/* { dg-do compile { target { powerpc64le-*-* } } } */
+/* { dg-skip-if "do not override -mcpu" { powerpc*-*-* } { "-mcpu=*" } { "-mcpu=power8" } } */
+/* { dg-options "-mcpu=power8 -O3 " } */
+/* { dg-final { scan-assembler "lxvd2x" } } */
+/* { dg-final { scan-assembler "stxvd2x" } } */
+/* { dg-final { scan-assembler-not "xxpermdi" } } */
+
+/* Verify that swap optimization works correctly for a truncating splat.  */
+
+/* Test case to resolve PR77613.  */
+
+void pr77613 (signed short a, signed short *x, signed short *y)
+{
+  unsigned long i;
+
+  for (i = 0; i < 1024; i++)
+    y[i] = a * x[i] + y[i];
+}