cmd/compile: optimize loads from readonly globals into constants on loong64

Ref: CL 141118
Update golang#26498

Change-Id: I9c4ad2bedc4d50bd273bbe9119a898d4fca95e45
Reviewed-on: https://go-review.googlesource.com/c/go/+/700875
Reviewed-by: abner chenc <[email protected]>
Reviewed-by: Michael Pratt <[email protected]>
Reviewed-by: Meidan Li <[email protected]>
Auto-Submit: Michael Pratt <[email protected]>
Reviewed-by: Cherry Mui <[email protected]>
LUCI-TryBot-Result: Go LUCI <[email protected]>

Author: sophie-zhao

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

@@ -949,3 +949,12 @@
 	&& isInlinableMemmove(dst, src, sz, config)
 	&& clobber(call)
 	=> (Move [sz] dst src mem)
+
+// fold readonly sym load
+(MOVBUload [off] {sym} (SB) _) && symIsRO(sym) => (MOVVconst [int64(read8(sym, int64(off)))])
+(MOVHUload [off] {sym} (SB) _) && symIsRO(sym) => (MOVVconst [int64(read16(sym, int64(off), config.ctxt.Arch.ByteOrder))])
+(MOVWUload [off] {sym} (SB) _) && symIsRO(sym) => (MOVVconst [int64(read32(sym, int64(off), config.ctxt.Arch.ByteOrder))])
+(MOVVload [off] {sym} (SB) _) && symIsRO(sym) => (MOVVconst [int64(read64(sym, int64(off), config.ctxt.Arch.ByteOrder))])
+(MOVBload [off] {sym} (SB) _) && symIsRO(sym) => (MOVVconst [int64(int8(read8(sym, int64(off))))])
+(MOVHload [off] {sym} (SB) _) && symIsRO(sym) => (MOVVconst [int64(int16(read16(sym, int64(off), config.ctxt.Arch.ByteOrder)))])
+(MOVWload [off] {sym} (SB) _) && symIsRO(sym) => (MOVVconst [int64(int32(read32(sym, int64(off), config.ctxt.Arch.ByteOrder)))])

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

@@ -39,6 +39,7 @@ func ConstantLoad() {
 	//   386:`MOVW\t\$12592, \(`,`MOVB\t\$50, 2\(`
 	//   arm:`MOVW\t\$48`,`MOVW\t\$49`,`MOVW\t\$50`
 	// arm64:`MOVD\t\$12592`,`MOVD\t\$50`
+	// loong64:`MOVV\t\$12592`,`MOVV\t\$50`
 	//  wasm:`I64Const\t\$12592`,`I64Store16\t\$0`,`I64Const\t\$50`,`I64Store8\t\$2`
 	// mips64:`MOVV\t\$48`,`MOVV\t\$49`,`MOVV\t\$50`
 	bsink = []byte("012")
@@ -48,6 +49,7 @@ func ConstantLoad() {
 	// amd64:`MOVL\t\$858927408`,`MOVW\t\$13620, 4\(`
 	//   386:`MOVL\t\$858927408`,`MOVW\t\$13620, 4\(`
 	// arm64:`MOVD\t\$858927408`,`MOVD\t\$13620`
+	// loong64:`MOVV\t\$858927408`,`MOVV\t\$13620`
 	//  wasm:`I64Const\t\$858927408`,`I64Store32\t\$0`,`I64Const\t\$13620`,`I64Store16\t\$4`
 	bsink = []byte("012345")
 
@@ -56,19 +58,23 @@ func ConstantLoad() {
 	// amd64:`MOVQ\t\$3978425819141910832`,`MOVQ\t\$7306073769690871863`
 	//   386:`MOVL\t\$858927408, \(`,`DUFFCOPY`
 	// arm64:`MOVD\t\$3978425819141910832`,`MOVD\t\$7306073769690871863`,`MOVD\t\$15`
+	// loong64:`MOVV\t\$3978425819141910832`,`MOVV\t\$7306073769690871863`,`MOVV\t\$15`
 	//  wasm:`I64Const\t\$3978425819141910832`,`I64Store\t\$0`,`I64Const\t\$7306073769690871863`,`I64Store\t\$7`
 	bsink = []byte("0123456789abcde")
 
 	// 56 = 0x38
 	// amd64:`MOVQ\t\$3978425819141910832`,`MOVB\t\$56`
+	// loong64:`MOVV\t\$3978425819141910832`,`MOVV\t\$56`
 	bsink = []byte("012345678")
 
 	// 14648 = 0x3938
 	// amd64:`MOVQ\t\$3978425819141910832`,`MOVW\t\$14648`
+	// loong64:`MOVV\t\$3978425819141910832`,`MOVV\t\$14648`
 	bsink = []byte("0123456789")
 
 	// 1650538808 = 0x62613938
 	// amd64:`MOVQ\t\$3978425819141910832`,`MOVL\t\$1650538808`
+	// loong64:`MOVV\t\$3978425819141910832`,`MOVV\t\$1650538808`
 	bsink = []byte("0123456789ab")
 }