cmd/compile: simplify the support for 32bit high multiply on loong64

Removes 152 instructions from the Go binary on loong64.

Change-Id: Icf8ead4f4ca965f51add85ac5e45c3cca8916401
Reviewed-on: https://go-review.googlesource.com/c/go/+/700335
Reviewed-by: Keith Randall <khr@google.com>
Auto-Submit: Michael Pratt <mpratt@google.com>
Reviewed-by: Michael Pratt <mpratt@google.com>
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>
Reviewed-by: Meidan Li <limeidan@loongson.cn>
Reviewed-by: abner chenc <chenguoqi@loongson.cn>

src/cmd/compile/internal/loong64/ssa.go

@@ -185,7 +185,7 @@ func ssaGenValue(s *ssagen.State, v *ssa.Value) {
 		ssa.OpLOONG64MULD,
 		ssa.OpLOONG64DIVF,
 		ssa.OpLOONG64DIVD,
-		ssa.OpLOONG64MULV, ssa.OpLOONG64MULHV, ssa.OpLOONG64MULHVU,
+		ssa.OpLOONG64MULV, ssa.OpLOONG64MULHV, ssa.OpLOONG64MULHVU, ssa.OpLOONG64MULH, ssa.OpLOONG64MULHU,
 		ssa.OpLOONG64DIVV, ssa.OpLOONG64REMV, ssa.OpLOONG64DIVVU, ssa.OpLOONG64REMVU,
 		ssa.OpLOONG64FCOPYSGD:
 		p := s.Prog(v.Op.Asm())

src/cmd/compile/internal/ssa/_gen/LOONG64.rules

@@ -17,8 +17,8 @@
 
 (Hmul64 ...)  => (MULHV  ...)
 (Hmul64u ...) => (MULHVU ...)
-(Hmul32 x y)  => (SRAVconst (MULV (SignExt32to64 x) (SignExt32to64 y)) [32])
+(Hmul32 ...)  => (MULH  ...)
-(Hmul32u x y) => (SRLVconst (MULV (ZeroExt32to64 x) (ZeroExt32to64 y)) [32])
+(Hmul32u ...) => (MULHU ...)
 
 (Div64 x y) => (DIVV x y)
 (Div64u ...) => (DIVVU ...)

src/cmd/compile/internal/ssa/_gen/LOONG64Ops.go

@@ -197,6 +197,8 @@ func init() {
 		{name: "MULV", argLength: 2, reg: gp21, asm: "MULV", commutative: true, typ: "Int64"},      // arg0 * arg1
 		{name: "MULHV", argLength: 2, reg: gp21, asm: "MULHV", commutative: true, typ: "Int64"},    // (arg0 * arg1) >> 64, signed
 		{name: "MULHVU", argLength: 2, reg: gp21, asm: "MULHVU", commutative: true, typ: "UInt64"}, // (arg0 * arg1) >> 64, unsigned
+		{name: "MULH", argLength: 2, reg: gp21, asm: "MULH", commutative: true, typ: "Int32"},      // (arg0 * arg1) >> 32, signed
+		{name: "MULHU", argLength: 2, reg: gp21, asm: "MULHU", commutative: true, typ: "UInt32"},   // (arg0 * arg1) >> 32, unsigned
 		{name: "DIVV", argLength: 2, reg: gp21, asm: "DIVV", typ: "Int64"},                         // arg0 / arg1, signed
 		{name: "DIVVU", argLength: 2, reg: gp21, asm: "DIVVU", typ: "UInt64"},                      // arg0 / arg1, unsigned
 		{name: "REMV", argLength: 2, reg: gp21, asm: "REMV", typ: "Int64"},                         // arg0 / arg1, signed

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

@@ -1795,6 +1795,8 @@ const (
 	OpLOONG64MULV
 	OpLOONG64MULHV
 	OpLOONG64MULHVU
+	OpLOONG64MULH
+	OpLOONG64MULHU
 	OpLOONG64DIVV
 	OpLOONG64DIVVU
 	OpLOONG64REMV
@@ -24139,6 +24141,36 @@ var opcodeTable = [...]opInfo{
 			},
 		},
 	},
+	{
+		name:        "MULH",
+		argLen:      2,
+		commutative: true,
+		asm:         loong64.AMULH,
+		reg: regInfo{
+			inputs: []inputInfo{
+				{0, 1073741816}, // R4 R5 R6 R7 R8 R9 R10 R11 R12 R13 R14 R15 R16 R17 R18 R19 R20 R21 g R23 R24 R25 R26 R27 R28 R29 R31
+				{1, 1073741817}, // ZERO R4 R5 R6 R7 R8 R9 R10 R11 R12 R13 R14 R15 R16 R17 R18 R19 R20 R21 g R23 R24 R25 R26 R27 R28 R29 R31
+			},
+			outputs: []outputInfo{
+				{0, 1071644664}, // R4 R5 R6 R7 R8 R9 R10 R11 R12 R13 R14 R15 R16 R17 R18 R19 R20 R21 R23 R24 R25 R26 R27 R28 R29 R31
+			},
+		},
+	},
+	{
+		name:        "MULHU",
+		argLen:      2,
+		commutative: true,
+		asm:         loong64.AMULHU,
+		reg: regInfo{
+			inputs: []inputInfo{
+				{0, 1073741816}, // R4 R5 R6 R7 R8 R9 R10 R11 R12 R13 R14 R15 R16 R17 R18 R19 R20 R21 g R23 R24 R25 R26 R27 R28 R29 R31
+				{1, 1073741817}, // ZERO R4 R5 R6 R7 R8 R9 R10 R11 R12 R13 R14 R15 R16 R17 R18 R19 R20 R21 g R23 R24 R25 R26 R27 R28 R29 R31
+			},
+			outputs: []outputInfo{
+				{0, 1071644664}, // R4 R5 R6 R7 R8 R9 R10 R11 R12 R13 R14 R15 R16 R17 R18 R19 R20 R21 R23 R24 R25 R26 R27 R28 R29 R31
+			},
+		},
+	},
 	{
 		name:   "DIVV",
 		argLen: 2,

src/cmd/compile/internal/ssa/rewriteLOONG64.go

@@ -296,9 +296,11 @@ func rewriteValueLOONG64(v *Value) bool {
 		v.Op = OpLOONG64LoweredGetClosurePtr
 		return true
 	case OpHmul32:
-		return rewriteValueLOONG64_OpHmul32(v)
+		v.Op = OpLOONG64MULH
+		return true
 	case OpHmul32u:
-		return rewriteValueLOONG64_OpHmul32u(v)
+		v.Op = OpLOONG64MULHU
+		return true
 	case OpHmul64:
 		v.Op = OpLOONG64MULHV
 		return true
@@ -1576,50 +1578,6 @@ func rewriteValueLOONG64_OpEqPtr(v *Value) bool {
 		return true
 	}
 }
-func rewriteValueLOONG64_OpHmul32(v *Value) bool {
-	v_1 := v.Args[1]
-	v_0 := v.Args[0]
-	b := v.Block
-	typ := &b.Func.Config.Types
-	// match: (Hmul32 x y)
-	// result: (SRAVconst (MULV (SignExt32to64 x) (SignExt32to64 y)) [32])
-	for {
-		x := v_0
-		y := v_1
-		v.reset(OpLOONG64SRAVconst)
-		v.AuxInt = int64ToAuxInt(32)
-		v0 := b.NewValue0(v.Pos, OpLOONG64MULV, typ.Int64)
-		v1 := b.NewValue0(v.Pos, OpSignExt32to64, typ.Int64)
-		v1.AddArg(x)
-		v2 := b.NewValue0(v.Pos, OpSignExt32to64, typ.Int64)
-		v2.AddArg(y)
-		v0.AddArg2(v1, v2)
-		v.AddArg(v0)
-		return true
-	}
-}
-func rewriteValueLOONG64_OpHmul32u(v *Value) bool {
-	v_1 := v.Args[1]
-	v_0 := v.Args[0]
-	b := v.Block
-	typ := &b.Func.Config.Types
-	// match: (Hmul32u x y)
-	// result: (SRLVconst (MULV (ZeroExt32to64 x) (ZeroExt32to64 y)) [32])
-	for {
-		x := v_0
-		y := v_1
-		v.reset(OpLOONG64SRLVconst)
-		v.AuxInt = int64ToAuxInt(32)
-		v0 := b.NewValue0(v.Pos, OpLOONG64MULV, typ.Int64)
-		v1 := b.NewValue0(v.Pos, OpZeroExt32to64, typ.UInt64)
-		v1.AddArg(x)
-		v2 := b.NewValue0(v.Pos, OpZeroExt32to64, typ.UInt64)
-		v2.AddArg(y)
-		v0.AddArg2(v1, v2)
-		v.AddArg(v0)
-		return true
-	}
-}
 func rewriteValueLOONG64_OpIsInBounds(v *Value) bool {
 	v_1 := v.Args[1]
 	v_0 := v.Args[0]