cmd/compile: loads from readonly globals into const for mips64x

Ref: CL 141118
Update #26498

Change-Id: If4ea55c080b9aa10183eefe81fefbd4072deaf3a
Reviewed-on: https://go-review.googlesource.com/c/go/+/280646
Trust: Meng Zhuo <mzh@golangcn.org>
Reviewed-by: Keith Randall <khr@golang.org>
Reviewed-by: Cherry Zhang <cherryyz@google.com>

3 files changed, 65 insertions, 0 deletions

diff --git a/src/cmd/compile/internal/ssa/gen/MIPS64.rules b/src/cmd/compile/internal/ssa/gen/MIPS64.rules
index bc51a0d53d..bb91dcd5ee 100644
--- a/src/cmd/compile/internal/ssa/gen/MIPS64.rules
+++ b/src/cmd/compile/internal/ssa/gen/MIPS64.rules
@@ -681,3 +681,9 @@
 (GTZ (MOVVconst [c]) yes no) && c <= 0 => (First no yes)
 (GEZ (MOVVconst [c]) yes no) && c >= 0 => (First yes no)
 (GEZ (MOVVconst [c]) yes no) && c <  0 => (First no yes)
+
+// fold readonly sym load
+(MOVBload [off] {sym} (SB) _) && symIsRO(sym) => (MOVVconst [int64(read8(sym, int64(off)))])
+(MOVHload [off] {sym} (SB) _) && symIsRO(sym) => (MOVVconst [int64(read16(sym, int64(off), config.ctxt.Arch.ByteOrder))])
+(MOVWload [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))])
diff --git a/src/cmd/compile/internal/ssa/rewriteMIPS64.go b/src/cmd/compile/internal/ssa/rewriteMIPS64.go
index 541bdd694a..79da4dfb72 100644
--- a/src/cmd/compile/internal/ssa/rewriteMIPS64.go
+++ b/src/cmd/compile/internal/ssa/rewriteMIPS64.go
@@ -2668,6 +2668,19 @@ func rewriteValueMIPS64_OpMIPS64MOVBload(v *Value) bool {
 		v.AddArg2(ptr, mem)
 		return true
 	}
+	// match: (MOVBload [off] {sym} (SB) _)
+	// cond: symIsRO(sym)
+	// result: (MOVVconst [int64(read8(sym, int64(off)))])
+	for {
+		off := auxIntToInt32(v.AuxInt)
+		sym := auxToSym(v.Aux)
+		if v_0.Op != OpSB || !(symIsRO(sym)) {
+			break
+		}
+		v.reset(OpMIPS64MOVVconst)
+		v.AuxInt = int64ToAuxInt(int64(read8(sym, int64(off))))
+		return true
+	}
 	return false
 }
 func rewriteValueMIPS64_OpMIPS64MOVBreg(v *Value) bool {
@@ -3232,6 +3245,8 @@ func rewriteValueMIPS64_OpMIPS64MOVHUreg(v *Value) bool {
 func rewriteValueMIPS64_OpMIPS64MOVHload(v *Value) bool {
 	v_1 := v.Args[1]
 	v_0 := v.Args[0]
+	b := v.Block
+	config := b.Func.Config
 	// match: (MOVHload [off1] {sym} (ADDVconst [off2] ptr) mem)
 	// cond: is32Bit(int64(off1)+off2)
 	// result: (MOVHload [off1+int32(off2)] {sym} ptr mem)
@@ -3275,6 +3290,19 @@ func rewriteValueMIPS64_OpMIPS64MOVHload(v *Value) bool {
 		v.AddArg2(ptr, mem)
 		return true
 	}
+	// match: (MOVHload [off] {sym} (SB) _)
+	// cond: symIsRO(sym)
+	// result: (MOVVconst [int64(read16(sym, int64(off), config.ctxt.Arch.ByteOrder))])
+	for {
+		off := auxIntToInt32(v.AuxInt)
+		sym := auxToSym(v.Aux)
+		if v_0.Op != OpSB || !(symIsRO(sym)) {
+			break
+		}
+		v.reset(OpMIPS64MOVVconst)
+		v.AuxInt = int64ToAuxInt(int64(read16(sym, int64(off), config.ctxt.Arch.ByteOrder)))
+		return true
+	}
 	return false
 }
 func rewriteValueMIPS64_OpMIPS64MOVHreg(v *Value) bool {
@@ -3544,6 +3572,8 @@ func rewriteValueMIPS64_OpMIPS64MOVHstorezero(v *Value) bool {
 func rewriteValueMIPS64_OpMIPS64MOVVload(v *Value) bool {
 	v_1 := v.Args[1]
 	v_0 := v.Args[0]
+	b := v.Block
+	config := b.Func.Config
 	// match: (MOVVload [off1] {sym} (ADDVconst [off2] ptr) mem)
 	// cond: is32Bit(int64(off1)+off2)
 	// result: (MOVVload [off1+int32(off2)] {sym} ptr mem)
@@ -3587,6 +3617,19 @@ func rewriteValueMIPS64_OpMIPS64MOVVload(v *Value) bool {
 		v.AddArg2(ptr, mem)
 		return true
 	}
+	// match: (MOVVload [off] {sym} (SB) _)
+	// cond: symIsRO(sym)
+	// result: (MOVVconst [int64(read64(sym, int64(off), config.ctxt.Arch.ByteOrder))])
+	for {
+		off := auxIntToInt32(v.AuxInt)
+		sym := auxToSym(v.Aux)
+		if v_0.Op != OpSB || !(symIsRO(sym)) {
+			break
+		}
+		v.reset(OpMIPS64MOVVconst)
+		v.AuxInt = int64ToAuxInt(int64(read64(sym, int64(off), config.ctxt.Arch.ByteOrder)))
+		return true
+	}
 	return false
 }
 func rewriteValueMIPS64_OpMIPS64MOVVnop(v *Value) bool {
@@ -3878,6 +3921,8 @@ func rewriteValueMIPS64_OpMIPS64MOVWUreg(v *Value) bool {
 func rewriteValueMIPS64_OpMIPS64MOVWload(v *Value) bool {
 	v_1 := v.Args[1]
 	v_0 := v.Args[0]
+	b := v.Block
+	config := b.Func.Config
 	// match: (MOVWload [off1] {sym} (ADDVconst [off2] ptr) mem)
 	// cond: is32Bit(int64(off1)+off2)
 	// result: (MOVWload [off1+int32(off2)] {sym} ptr mem)
@@ -3921,6 +3966,19 @@ func rewriteValueMIPS64_OpMIPS64MOVWload(v *Value) bool {
 		v.AddArg2(ptr, mem)
 		return true
 	}
+	// match: (MOVWload [off] {sym} (SB) _)
+	// cond: symIsRO(sym)
+	// result: (MOVVconst [int64(read32(sym, int64(off), config.ctxt.Arch.ByteOrder))])
+	for {
+		off := auxIntToInt32(v.AuxInt)
+		sym := auxToSym(v.Aux)
+		if v_0.Op != OpSB || !(symIsRO(sym)) {
+			break
+		}
+		v.reset(OpMIPS64MOVVconst)
+		v.AuxInt = int64ToAuxInt(int64(read32(sym, int64(off), config.ctxt.Arch.ByteOrder)))
+		return true
+	}
 	return false
 }
 func rewriteValueMIPS64_OpMIPS64MOVWreg(v *Value) bool {
diff --git a/test/codegen/strings.go b/test/codegen/strings.go
index 0859e241cb..19e1dbda51 100644
--- a/test/codegen/strings.go
+++ b/test/codegen/strings.go
@@ -30,6 +30,7 @@ func ConstantLoad() {
 	//   arm:`MOVW\t\$48`,`MOVW\t\$49`,`MOVW\t\$50`
 	// arm64:`MOVD\t\$12592`,`MOVD\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")
 
 	// 858927408 = 0x33323130