cmd/asm,cmd/internal/obj/ppc64: add VPERMXOR to ppc64 assembler

VPERMXOR is missing from the Go assembler for ppc64. It has the
same format as VPERM. It was requested by an external user so
they could write an optimized algorithm in asm.

Change-Id: Icf4c682f7f46716ccae64e6ae3d62e8cec67f6c1
Reviewed-on: https://go-review.googlesource.com/c/151578
Run-TryBot: Lynn Boger <laboger@linux.vnet.ibm.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Carlos Eduardo Seo <cseo@linux.vnet.ibm.com>

src/cmd/asm/internal/asm/testdata/ppc64.s

@@ -948,6 +948,7 @@ label1:
 //	<MNEMONIC> VRA,VRB,VRC,VRT produces
 //	<mnemonic> VRT,VRA,VRB,VRC
 	VPERM V3, V2, V1, V0
+	VPERMXOR V3, V2, V1, V0
 
 //	Vector bit permute, VX-form
 //	<MNEMONIC> VRA,VRB,VRT produces

src/cmd/internal/obj/ppc64/a.out.go

@@ -903,6 +903,7 @@ const (
 	AVCMPNEZB
 	AVCMPNEZBCC
 	AVPERM
+	AVPERMXOR
 	AVBPERMQ
 	AVBPERMD
 	AVSEL

src/cmd/internal/obj/ppc64/anames.go

@@ -493,6 +493,7 @@ var Anames = []string{
 	"VCMPNEZB",
 	"VCMPNEZBCC",
 	"VPERM",
+	"VPERMXOR",
 	"VBPERMQ",
 	"VBPERMD",
 	"VSEL",

src/cmd/internal/obj/ppc64/asm9.go

@@ -1498,7 +1498,7 @@ func buildop(ctxt *obj.Link) {
 			opset(AVCMPNEZBCC, r0)
 
 		case AVPERM: /* vperm */
-			opset(AVPERM, r0)
+			opset(AVPERMXOR, r0)
 
 		case AVBPERMQ: /* vbpermq, vbpermd */
 			opset(AVBPERMD, r0)
@@ -4503,6 +4503,8 @@ func (c *ctxt9) oprrr(a obj.As) uint32 {
 
 	case AVPERM:
 		return OPVX(4, 43, 0, 0) /* vperm - v2.03 */
+	case AVPERMXOR:
+		return OPVX(4, 45, 0, 0) /* vpermxor - v2.03 */
 
 	case AVSEL:
 		return OPVX(4, 42, 0, 0) /* vsel - v2.03 */