cmd/compile: amd64, allow XCHG on stack pointers

XCHG needs to allow the stack pointer as an argument because we have a
rewrite that incorporates the address of a local variable into the
instruction.

Fixes #19184

Change-Id: Ic438e6e1946332cdce3864d15abecd41b911b2a9
Reviewed-on: https://go-review.googlesource.com/37253
Run-TryBot: Keith Randall <khr@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Cherry Zhang <cherryyz@google.com>

src/cmd/compile/internal/ssa/gen/AMD64Ops.go

@@ -134,7 +134,7 @@ func init() {
 		gpstoreconst    = regInfo{inputs: []regMask{gpspsb, 0}}
 		gpstoreidx      = regInfo{inputs: []regMask{gpspsb, gpsp, gpsp, 0}}
 		gpstoreconstidx = regInfo{inputs: []regMask{gpspsb, gpsp, 0}}
-		gpstorexchg     = regInfo{inputs: []regMask{gp, gp, 0}, outputs: []regMask{gp}}
+		gpstorexchg     = regInfo{inputs: []regMask{gp, gpspsb, 0}, outputs: []regMask{gp}}
 		cmpxchg         = regInfo{inputs: []regMask{gp, ax, gp, 0}, outputs: []regMask{gp, 0}, clobbers: ax}
 
 		fp01     = regInfo{inputs: nil, outputs: fponly}

src/cmd/compile/internal/ssa/opGen.go

@@ -7635,8 +7635,8 @@ var opcodeTable = [...]opInfo{
 		asm:            x86.AXCHGL,
 		reg: regInfo{
 			inputs: []inputInfo{
-				{0, 65519}, // AX CX DX BX BP SI DI R8 R9 R10 R11 R12 R13 R14 R15
-				{1, 65519}, // AX CX DX BX BP SI DI R8 R9 R10 R11 R12 R13 R14 R15
+				{0, 65519},      // AX CX DX BX BP SI DI R8 R9 R10 R11 R12 R13 R14 R15
+				{1, 4295032831}, // AX CX DX BX SP BP SI DI R8 R9 R10 R11 R12 R13 R14 R15 SB
 			},
 			outputs: []outputInfo{
 				{0, 65519}, // AX CX DX BX BP SI DI R8 R9 R10 R11 R12 R13 R14 R15
@@ -7652,8 +7652,8 @@ var opcodeTable = [...]opInfo{
 		asm:            x86.AXCHGQ,
 		reg: regInfo{
 			inputs: []inputInfo{
-				{0, 65519}, // AX CX DX BX BP SI DI R8 R9 R10 R11 R12 R13 R14 R15
-				{1, 65519}, // AX CX DX BX BP SI DI R8 R9 R10 R11 R12 R13 R14 R15
+				{0, 65519},      // AX CX DX BX BP SI DI R8 R9 R10 R11 R12 R13 R14 R15
+				{1, 4295032831}, // AX CX DX BX SP BP SI DI R8 R9 R10 R11 R12 R13 R14 R15 SB
 			},
 			outputs: []outputInfo{
 				{0, 65519}, // AX CX DX BX BP SI DI R8 R9 R10 R11 R12 R13 R14 R15
@@ -7670,8 +7670,8 @@ var opcodeTable = [...]opInfo{
 		asm:            x86.AXADDL,
 		reg: regInfo{
 			inputs: []inputInfo{
-				{0, 65519}, // AX CX DX BX BP SI DI R8 R9 R10 R11 R12 R13 R14 R15
-				{1, 65519}, // AX CX DX BX BP SI DI R8 R9 R10 R11 R12 R13 R14 R15
+				{0, 65519},      // AX CX DX BX BP SI DI R8 R9 R10 R11 R12 R13 R14 R15
+				{1, 4295032831}, // AX CX DX BX SP BP SI DI R8 R9 R10 R11 R12 R13 R14 R15 SB
 			},
 			outputs: []outputInfo{
 				{0, 65519}, // AX CX DX BX BP SI DI R8 R9 R10 R11 R12 R13 R14 R15
@@ -7688,8 +7688,8 @@ var opcodeTable = [...]opInfo{
 		asm:            x86.AXADDQ,
 		reg: regInfo{
 			inputs: []inputInfo{
-				{0, 65519}, // AX CX DX BX BP SI DI R8 R9 R10 R11 R12 R13 R14 R15
-				{1, 65519}, // AX CX DX BX BP SI DI R8 R9 R10 R11 R12 R13 R14 R15
+				{0, 65519},      // AX CX DX BX BP SI DI R8 R9 R10 R11 R12 R13 R14 R15
+				{1, 4295032831}, // AX CX DX BX SP BP SI DI R8 R9 R10 R11 R12 R13 R14 R15 SB
 			},
 			outputs: []outputInfo{
 				{0, 65519}, // AX CX DX BX BP SI DI R8 R9 R10 R11 R12 R13 R14 R15