cmd/internal/obj/loong64: add aliases to 32-bit arithmetic instructions

Both the MULW and MUL instructions point to the mul.w instruction
in the loong64 ISA. Previously, MULW was not encoded; now it is
encoded and used as an alias for MUL.
The same applies to the following instructions: ADD, SUB, DIV.
For consistency, we have added additional aliases for DIVU, REM and REMU.

Change-Id: Iba201a3c4c2893ff7d301ef877fad9c81e54291b
Reviewed-on: https://go-review.googlesource.com/c/go/+/721523
Reviewed-by: Cherry Mui <cherryyz@google.com>
Auto-Submit: abner chenc <chenguoqi@loongson.cn>
Reviewed-by: abner chenc <chenguoqi@loongson.cn>
Reviewed-by: Meidan Li <limeidan@loongson.cn>
Reviewed-by: Dmitri Shuralyov <dmitshur@google.com>
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>

3 files changed, 21 insertions, 8 deletions

diff --git a/src/cmd/internal/obj/loong64/a.out.go b/src/cmd/internal/obj/loong64/a.out.go
index 96f0889199..2458fb2e8e 100644
--- a/src/cmd/internal/obj/loong64/a.out.go
+++ b/src/cmd/internal/obj/loong64/a.out.go
@@ -468,6 +468,7 @@ const (
 	ADIVF
 	ADIVU
 	ADIVW
+	ADIVWU
 
 	ALL
 	ALLV
@@ -508,7 +509,9 @@ const (
 	ANOR
 	AOR
 	AREM
+	AREMW
 	AREMU
+	AREMWU
 
 	ARFE
 
diff --git a/src/cmd/internal/obj/loong64/anames.go b/src/cmd/internal/obj/loong64/anames.go
index 0ee911401f..18f818ceba 100644
--- a/src/cmd/internal/obj/loong64/anames.go
+++ b/src/cmd/internal/obj/loong64/anames.go
@@ -43,6 +43,7 @@ var Anames = []string{
 	"DIVF",
 	"DIVU",
 	"DIVW",
+	"DIVWU",
 	"LL",
 	"LLV",
 	"LUI",
@@ -74,7 +75,9 @@ var Anames = []string{
 	"NOR",
 	"OR",
 	"REM",
+	"REMW",
 	"REMU",
+	"REMWU",
 	"RFE",
 	"SC",
 	"SCV",
diff --git a/src/cmd/internal/obj/loong64/asm.go b/src/cmd/internal/obj/loong64/asm.go
index 9aff344931..6a23460098 100644
--- a/src/cmd/internal/obj/loong64/asm.go
+++ b/src/cmd/internal/obj/loong64/asm.go
@@ -1428,6 +1428,7 @@ func buildop(ctxt *obj.Link) {
 			opset(AFTINTRNEVD, r0)
 
 		case AADD:
+			opset(AADDW, r0)
 			opset(ASGT, r0)
 			opset(ASGTU, r0)
 			opset(AADDU, r0)
@@ -1512,18 +1513,24 @@ func buildop(ctxt *obj.Link) {
 			opset(ABSTRINSV, r0)
 
 		case ASUB:
+			opset(ASUBW, r0)
 			opset(ASUBU, r0)
 			opset(ANOR, r0)
 			opset(ASUBV, r0)
 			opset(ASUBVU, r0)
 			opset(AMUL, r0)
+			opset(AMULW, r0)
 			opset(AMULU, r0)
 			opset(AMULH, r0)
 			opset(AMULHU, r0)
 			opset(AREM, r0)
+			opset(AREMW, r0)
 			opset(AREMU, r0)
+			opset(AREMWU, r0)
 			opset(ADIV, r0)
+			opset(ADIVW, r0)
 			opset(ADIVU, r0)
+			opset(ADIVWU, r0)
 			opset(AMULV, r0)
 			opset(AMULVU, r0)
 			opset(AMULHV, r0)
@@ -3244,7 +3251,7 @@ func (c *ctxt0) oprrrr(a obj.As) uint32 {
 
 func (c *ctxt0) oprrr(a obj.As) uint32 {
 	switch a {
-	case AADD:
+	case AADD, AADDW:
 		return 0x20 << 15
 	case AADDU:
 		return 0x20 << 15
@@ -3266,7 +3273,7 @@ func (c *ctxt0) oprrr(a obj.As) uint32 {
 		return 0x2c << 15 // orn
 	case AANDN:
 		return 0x2d << 15 // andn
-	case ASUB:
+	case ASUB, ASUBW:
 		return 0x22 << 15
 	case ASUBU, ANEGW:
 		return 0x22 << 15
@@ -3297,7 +3304,7 @@ func (c *ctxt0) oprrr(a obj.As) uint32 {
 	case ASUBVU, ANEGV:
 		return 0x23 << 15
 
-	case AMUL:
+	case AMUL, AMULW:
 		return 0x38 << 15 // mul.w
 	case AMULU:
 		return 0x38 << 15 // mul.w
@@ -3317,17 +3324,17 @@ func (c *ctxt0) oprrr(a obj.As) uint32 {
 		return 0x3e << 15 // mulw.d.w
 	case AMULWVWU:
 		return 0x3f << 15 // mulw.d.wu
-	case ADIV:
+	case ADIV, ADIVW:
 		return 0x40 << 15 // div.w
-	case ADIVU:
+	case ADIVU, ADIVWU:
 		return 0x42 << 15 // div.wu
 	case ADIVV:
 		return 0x44 << 15 // div.d
 	case ADIVVU:
 		return 0x46 << 15 // div.du
-	case AREM:
+	case AREM, AREMW:
 		return 0x41 << 15 // mod.w
-	case AREMU:
+	case AREMU, AREMWU:
 		return 0x43 << 15 // mod.wu
 	case AREMV:
 		return 0x45 << 15 // mod.d
@@ -4485,7 +4492,7 @@ func (c *ctxt0) opir(a obj.As) uint32 {
 
 func (c *ctxt0) opirr(a obj.As) uint32 {
 	switch a {
-	case AADD, AADDU:
+	case AADD, AADDW, AADDU:
 		return 0x00a << 22
 	case ASGT:
 		return 0x008 << 22