cmd/compile, math: make math.{Abs,Copysign} intrinsics on loong64

goos: linux
goarch: loong64
pkg: math
cpu: Loongson-3A6000 @ 2500.00MHz
         │  old.bench   │              new.bench               │
         │    sec/op    │    sec/op     vs base                │
Copysign   1.9710n ± 0%   0.8006n ± 0%  -59.38% (p=0.000 n=10)
Abs        1.8745n ± 0%   0.8006n ± 0%  -57.29% (p=0.000 n=10)
geomean     1.922n        0.8006n       -58.35%

goos: linux
goarch: loong64
pkg: math
cpu: Loongson-3A5000 @ 2500.00MHz
         │  old.bench   │              new.bench               │
         │    sec/op    │    sec/op     vs base                │
Copysign   2.4020n ± 0%   0.9006n ± 0%  -62.51% (p=0.000 n=10)
Abs        2.4020n ± 0%   0.8005n ± 0%  -66.67% (p=0.000 n=10)
geomean     2.402n        0.8491n       -64.65%

Updates #59120.

Change-Id: Ic409e1f4d15ad15cb3568a5aaa100046e9302842
Reviewed-on: https://go-review.googlesource.com/c/go/+/580280
Reviewed-by: Qiqi Huang <[email protected]>
Reviewed-by: Meidan Li <[email protected]>
Reviewed-by: abner chenc <[email protected]>
Reviewed-by: Michael Knyszek <[email protected]>
LUCI-TryBot-Result: Go LUCI <[email protected]>
Reviewed-by: David Chase <[email protected]>

Author: sophie-zhao

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

@@ -177,7 +177,8 @@ func ssaGenValue(s *ssagen.State, v *ssa.Value) {
 		ssa.OpLOONG64DIVF,
 		ssa.OpLOONG64DIVD,
 		ssa.OpLOONG64MULV, ssa.OpLOONG64MULHV, ssa.OpLOONG64MULHVU,
-		ssa.OpLOONG64DIVV, ssa.OpLOONG64REMV, ssa.OpLOONG64DIVVU, ssa.OpLOONG64REMVU:
+		ssa.OpLOONG64DIVV, ssa.OpLOONG64REMV, ssa.OpLOONG64DIVVU, ssa.OpLOONG64REMVU,
+		ssa.OpLOONG64FCOPYSGD:
 		p := s.Prog(v.Op.Asm())
 		p.From.Type = obj.TYPE_REG
 		p.From.Reg = v.Args[1].Reg()
@@ -420,7 +421,8 @@ func ssaGenValue(s *ssagen.State, v *ssa.Value) {
 		ssa.OpLOONG64NEGF,
 		ssa.OpLOONG64NEGD,
 		ssa.OpLOONG64SQRTD,
-		ssa.OpLOONG64SQRTF:
+		ssa.OpLOONG64SQRTF,
+		ssa.OpLOONG64ABSD:
 		p := s.Prog(v.Op.Asm())
 		p.From.Type = obj.TYPE_REG
 		p.From.Reg = v.Args[0].Reg()

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

@@ -129,8 +129,11 @@
 
 (Com(64|32|16|8) x) => (NOR (MOVVconst [0]) x)
 
+// math package intrinsics
 (Sqrt ...) => (SQRTD ...)
 (Sqrt32 ...) => (SQRTF ...)
+(Abs ...) => (ABSD ...)
+(Copysign ...) => (FCOPYSGD ...)
 
 (Min(64|32)F ...) => (FMIN(D|F) ...)
 (Max(64|32)F ...) => (FMAX(D|F) ...)

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

@@ -201,6 +201,9 @@ func init() {
 		{name: "MASKEQZ", argLength: 2, reg: gp21, asm: "MASKEQZ"}, // returns 0 if arg1 == 0, otherwise returns arg0
 		{name: "MASKNEZ", argLength: 2, reg: gp21, asm: "MASKNEZ"}, // returns 0 if arg1 != 0, otherwise returns arg0
 
+		{name: "ABSD", argLength: 1, reg: fp11, asm: "ABSD"},         // abs(arg0), float64
+		{name: "FCOPYSGD", argLength: 2, reg: fp21, asm: "FCOPYSGD"}, // float64
+
 		// shifts
 		{name: "SLLV", argLength: 2, reg: gp21, asm: "SLLV"},                      // arg0 << arg1, shift amount is mod 64
 		{name: "SLLVconst", argLength: 1, reg: gp11, asm: "SLLV", aux: "Int64"},   // arg0 << auxInt

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

@@ -4721,12 +4721,12 @@ func InitTables() {
 		func(s *state, n *ir.CallExpr, args []*ssa.Value) *ssa.Value {
 			return s.newValue1(ssa.OpAbs, types.Types[types.TFLOAT64], args[0])
 		},
-		sys.ARM64, sys.ARM, sys.PPC64, sys.RISCV64, sys.Wasm, sys.MIPS, sys.MIPS64)
+		sys.ARM64, sys.ARM, sys.Loong64, sys.PPC64, sys.RISCV64, sys.Wasm, sys.MIPS, sys.MIPS64)
 	addF("math", "Copysign",
 		func(s *state, n *ir.CallExpr, args []*ssa.Value) *ssa.Value {
 			return s.newValue2(ssa.OpCopysign, types.Types[types.TFLOAT64], args[0], args[1])
 		},
-		sys.PPC64, sys.RISCV64, sys.Wasm)
+		sys.Loong64, sys.PPC64, sys.RISCV64, sys.Wasm)
 	addF("math", "FMA",
 		func(s *state, n *ir.CallExpr, args []*ssa.Value) *ssa.Value {
 			return s.newValue3(ssa.OpFMA, types.Types[types.TFLOAT64], args[0], args[1], args[2])