[dev.simd] runtime: save Z16-Z31 registers in async preempt

The register allocation will use the upper register soon, this CL is to
enable that.

Change-Id: I4d7285e08b95f4e6ebee72594dfbe8d1199f09ed
Reviewed-on: https://go-review.googlesource.com/c/go/+/686498
TryBot-Bypass: David Chase <drchase@google.com>
Reviewed-by: Cherry Mui <cherryyz@google.com>
Commit-Queue: David Chase <drchase@google.com>

src/runtime/mkpreempt.go

@@ -300,7 +300,7 @@ func genAMD64(g *gen) {
 	// Create layouts for X, Y, and Z registers.
 	const (
 		numXRegs = 16
-		numZRegs = 16 // TODO: If we start using upper registers, change to 32
+		numZRegs = 32
 		numKRegs = 8
 	)
 	lZRegs := layout{sp: xReg} // Non-GP registers

src/runtime/preempt_amd64.go

@@ -19,6 +19,22 @@ type xRegs struct {
 	Z13 [64]byte
 	Z14 [64]byte
 	Z15 [64]byte
+	Z16 [64]byte
+	Z17 [64]byte
+	Z18 [64]byte
+	Z19 [64]byte
+	Z20 [64]byte
+	Z21 [64]byte
+	Z22 [64]byte
+	Z23 [64]byte
+	Z24 [64]byte
+	Z25 [64]byte
+	Z26 [64]byte
+	Z27 [64]byte
+	Z28 [64]byte
+	Z29 [64]byte
+	Z30 [64]byte
+	Z31 [64]byte
 	K0  uint64
 	K1  uint64
 	K2  uint64

src/runtime/preempt_amd64.s

@@ -95,14 +95,30 @@ saveAVX512:
 	VMOVDQU64 Z13, 832(AX)
 	VMOVDQU64 Z14, 896(AX)
 	VMOVDQU64 Z15, 960(AX)
-	KMOVQ K0, 1024(AX)
-	KMOVQ K1, 1032(AX)
-	KMOVQ K2, 1040(AX)
-	KMOVQ K3, 1048(AX)
-	KMOVQ K4, 1056(AX)
-	KMOVQ K5, 1064(AX)
-	KMOVQ K6, 1072(AX)
-	KMOVQ K7, 1080(AX)
+	VMOVDQU64 Z16, 1024(AX)
+	VMOVDQU64 Z17, 1088(AX)
+	VMOVDQU64 Z18, 1152(AX)
+	VMOVDQU64 Z19, 1216(AX)
+	VMOVDQU64 Z20, 1280(AX)
+	VMOVDQU64 Z21, 1344(AX)
+	VMOVDQU64 Z22, 1408(AX)
+	VMOVDQU64 Z23, 1472(AX)
+	VMOVDQU64 Z24, 1536(AX)
+	VMOVDQU64 Z25, 1600(AX)
+	VMOVDQU64 Z26, 1664(AX)
+	VMOVDQU64 Z27, 1728(AX)
+	VMOVDQU64 Z28, 1792(AX)
+	VMOVDQU64 Z29, 1856(AX)
+	VMOVDQU64 Z30, 1920(AX)
+	VMOVDQU64 Z31, 1984(AX)
+	KMOVQ K0, 2048(AX)
+	KMOVQ K1, 2056(AX)
+	KMOVQ K2, 2064(AX)
+	KMOVQ K3, 2072(AX)
+	KMOVQ K4, 2080(AX)
+	KMOVQ K5, 2088(AX)
+	KMOVQ K6, 2096(AX)
+	KMOVQ K7, 2104(AX)
 	JMP preempt
 preempt:
 	CALL ·asyncPreempt2(SB)
@@ -153,14 +169,30 @@ restoreAVX2:
 	VMOVDQU 0(AX), Y0
 	JMP restoreGPs
 restoreAVX512:
-	KMOVQ 1080(AX), K7
-	KMOVQ 1072(AX), K6
-	KMOVQ 1064(AX), K5
-	KMOVQ 1056(AX), K4
-	KMOVQ 1048(AX), K3
-	KMOVQ 1040(AX), K2
-	KMOVQ 1032(AX), K1
-	KMOVQ 1024(AX), K0
+	KMOVQ 2104(AX), K7
+	KMOVQ 2096(AX), K6
+	KMOVQ 2088(AX), K5
+	KMOVQ 2080(AX), K4
+	KMOVQ 2072(AX), K3
+	KMOVQ 2064(AX), K2
+	KMOVQ 2056(AX), K1
+	KMOVQ 2048(AX), K0
+	VMOVDQU64 1984(AX), Z31
+	VMOVDQU64 1920(AX), Z30
+	VMOVDQU64 1856(AX), Z29
+	VMOVDQU64 1792(AX), Z28
+	VMOVDQU64 1728(AX), Z27
+	VMOVDQU64 1664(AX), Z26
+	VMOVDQU64 1600(AX), Z25
+	VMOVDQU64 1536(AX), Z24
+	VMOVDQU64 1472(AX), Z23
+	VMOVDQU64 1408(AX), Z22
+	VMOVDQU64 1344(AX), Z21
+	VMOVDQU64 1280(AX), Z20
+	VMOVDQU64 1216(AX), Z19
+	VMOVDQU64 1152(AX), Z18
+	VMOVDQU64 1088(AX), Z17
+	VMOVDQU64 1024(AX), Z16
 	VMOVDQU64 960(AX), Z15
 	VMOVDQU64 896(AX), Z14
 	VMOVDQU64 832(AX), Z13