cmd/compile: stop MOVW-ing -1 as SRA shift amount in mips

The shift amount in SRAconst needs to be in the [0,31] range, so stop
MOVWing -1 to SRA in the Rsh lowering rules.

Also see CL 270117.

Passes

  $ GOARCH=mips go build -toolexec 'toolstash -cmp' -a std
  $ GOARCH=mipsle go build -toolexec 'toolstash -cmp' -a std

Updates #42587

Change-Id: Ib5eb99b82310e404cc2d6f0c619b21b8a15406ce
Reviewed-on: https://go-review.googlesource.com/c/go/+/270558
Trust: Alberto Donizetti <alb.donizetti@gmail.com>
Run-TryBot: Alberto Donizetti <alb.donizetti@gmail.com>
TryBot-Result: Go Bot <gobot@golang.org>
Reviewed-by: Cherry Zhang <cherryyz@google.com>
diff --git a/src/cmd/compile/internal/ssa/gen/MIPS.rules b/src/cmd/compile/internal/ssa/gen/MIPS.rules
index 7dcac9c..470cc66 100644
--- a/src/cmd/compile/internal/ssa/gen/MIPS.rules
+++ b/src/cmd/compile/internal/ssa/gen/MIPS.rules
@@ -96,17 +96,17 @@
 (Rsh8Ux16 <t> x y) => (CMOVZ (SRL <t> (ZeroExt8to32 x) (ZeroExt16to32 y) ) (MOVWconst [0]) (SGTUconst [32] (ZeroExt16to32 y)))
 (Rsh8Ux8 <t> x y)  => (CMOVZ (SRL <t> (ZeroExt8to32 x) (ZeroExt8to32 y) ) (MOVWconst [0]) (SGTUconst [32] (ZeroExt8to32 y)))
 
-(Rsh32x32 x y) => (SRA x ( CMOVZ <typ.UInt32> y (MOVWconst [-1]) (SGTUconst [32] y)))
-(Rsh32x16 x y) => (SRA x ( CMOVZ <typ.UInt32> (ZeroExt16to32 y) (MOVWconst [-1]) (SGTUconst [32] (ZeroExt16to32 y))))
-(Rsh32x8 x y)  => (SRA x ( CMOVZ <typ.UInt32> (ZeroExt8to32 y) (MOVWconst [-1]) (SGTUconst [32] (ZeroExt8to32 y))))
+(Rsh32x32 x y) => (SRA x ( CMOVZ <typ.UInt32> y (MOVWconst [31]) (SGTUconst [32] y)))
+(Rsh32x16 x y) => (SRA x ( CMOVZ <typ.UInt32> (ZeroExt16to32 y) (MOVWconst [31]) (SGTUconst [32] (ZeroExt16to32 y))))
+(Rsh32x8 x y)  => (SRA x ( CMOVZ <typ.UInt32> (ZeroExt8to32 y) (MOVWconst [31]) (SGTUconst [32] (ZeroExt8to32 y))))
 
-(Rsh16x32 x y) => (SRA (SignExt16to32 x) ( CMOVZ <typ.UInt32> y (MOVWconst [-1]) (SGTUconst [32] y)))
-(Rsh16x16 x y) => (SRA (SignExt16to32 x) ( CMOVZ <typ.UInt32> (ZeroExt16to32 y) (MOVWconst [-1]) (SGTUconst [32] (ZeroExt16to32 y))))
-(Rsh16x8 x y)  => (SRA (SignExt16to32 x) ( CMOVZ <typ.UInt32> (ZeroExt8to32 y) (MOVWconst [-1]) (SGTUconst [32] (ZeroExt8to32 y))))
+(Rsh16x32 x y) => (SRA (SignExt16to32 x) ( CMOVZ <typ.UInt32> y (MOVWconst [31]) (SGTUconst [32] y)))
+(Rsh16x16 x y) => (SRA (SignExt16to32 x) ( CMOVZ <typ.UInt32> (ZeroExt16to32 y) (MOVWconst [31]) (SGTUconst [32] (ZeroExt16to32 y))))
+(Rsh16x8 x y)  => (SRA (SignExt16to32 x) ( CMOVZ <typ.UInt32> (ZeroExt8to32 y) (MOVWconst [31]) (SGTUconst [32] (ZeroExt8to32 y))))
 
-(Rsh8x32 x y) => (SRA (SignExt16to32 x) ( CMOVZ <typ.UInt32> y (MOVWconst [-1]) (SGTUconst [32] y)))
-(Rsh8x16 x y) => (SRA (SignExt16to32 x) ( CMOVZ <typ.UInt32> (ZeroExt16to32 y) (MOVWconst [-1]) (SGTUconst [32] (ZeroExt16to32 y))))
-(Rsh8x8 x y)  => (SRA (SignExt16to32 x) ( CMOVZ <typ.UInt32> (ZeroExt8to32 y) (MOVWconst [-1]) (SGTUconst [32] (ZeroExt8to32 y))))
+(Rsh8x32 x y) => (SRA (SignExt16to32 x) ( CMOVZ <typ.UInt32> y (MOVWconst [31]) (SGTUconst [32] y)))
+(Rsh8x16 x y) => (SRA (SignExt16to32 x) ( CMOVZ <typ.UInt32> (ZeroExt16to32 y) (MOVWconst [31]) (SGTUconst [32] (ZeroExt16to32 y))))
+(Rsh8x8 x y)  => (SRA (SignExt16to32 x) ( CMOVZ <typ.UInt32> (ZeroExt8to32 y) (MOVWconst [31]) (SGTUconst [32] (ZeroExt8to32 y))))
 
 // rotates
 (RotateLeft8  <t> x (MOVWconst [c])) => (Or8  (Lsh8x32 <t>  x (MOVWconst [c&7]))  (Rsh8Ux32 <t> x (MOVWconst [-c&7])))
diff --git a/src/cmd/compile/internal/ssa/rewriteMIPS.go b/src/cmd/compile/internal/ssa/rewriteMIPS.go
index cfe39d7..bbc3310 100644
--- a/src/cmd/compile/internal/ssa/rewriteMIPS.go
+++ b/src/cmd/compile/internal/ssa/rewriteMIPS.go
@@ -5697,7 +5697,7 @@
 	b := v.Block
 	typ := &b.Func.Config.Types
 	// match: (Rsh16x16 x y)
-	// result: (SRA (SignExt16to32 x) ( CMOVZ <typ.UInt32> (ZeroExt16to32 y) (MOVWconst [-1]) (SGTUconst [32] (ZeroExt16to32 y))))
+	// result: (SRA (SignExt16to32 x) ( CMOVZ <typ.UInt32> (ZeroExt16to32 y) (MOVWconst [31]) (SGTUconst [32] (ZeroExt16to32 y))))
 	for {
 		x := v_0
 		y := v_1
@@ -5708,7 +5708,7 @@
 		v2 := b.NewValue0(v.Pos, OpZeroExt16to32, typ.UInt32)
 		v2.AddArg(y)
 		v3 := b.NewValue0(v.Pos, OpMIPSMOVWconst, typ.UInt32)
-		v3.AuxInt = int32ToAuxInt(-1)
+		v3.AuxInt = int32ToAuxInt(31)
 		v4 := b.NewValue0(v.Pos, OpMIPSSGTUconst, typ.Bool)
 		v4.AuxInt = int32ToAuxInt(32)
 		v4.AddArg(v2)
@@ -5723,7 +5723,7 @@
 	b := v.Block
 	typ := &b.Func.Config.Types
 	// match: (Rsh16x32 x y)
-	// result: (SRA (SignExt16to32 x) ( CMOVZ <typ.UInt32> y (MOVWconst [-1]) (SGTUconst [32] y)))
+	// result: (SRA (SignExt16to32 x) ( CMOVZ <typ.UInt32> y (MOVWconst [31]) (SGTUconst [32] y)))
 	for {
 		x := v_0
 		y := v_1
@@ -5732,7 +5732,7 @@
 		v0.AddArg(x)
 		v1 := b.NewValue0(v.Pos, OpMIPSCMOVZ, typ.UInt32)
 		v2 := b.NewValue0(v.Pos, OpMIPSMOVWconst, typ.UInt32)
-		v2.AuxInt = int32ToAuxInt(-1)
+		v2.AuxInt = int32ToAuxInt(31)
 		v3 := b.NewValue0(v.Pos, OpMIPSSGTUconst, typ.Bool)
 		v3.AuxInt = int32ToAuxInt(32)
 		v3.AddArg(y)
@@ -5794,7 +5794,7 @@
 	b := v.Block
 	typ := &b.Func.Config.Types
 	// match: (Rsh16x8 x y)
-	// result: (SRA (SignExt16to32 x) ( CMOVZ <typ.UInt32> (ZeroExt8to32 y) (MOVWconst [-1]) (SGTUconst [32] (ZeroExt8to32 y))))
+	// result: (SRA (SignExt16to32 x) ( CMOVZ <typ.UInt32> (ZeroExt8to32 y) (MOVWconst [31]) (SGTUconst [32] (ZeroExt8to32 y))))
 	for {
 		x := v_0
 		y := v_1
@@ -5805,7 +5805,7 @@
 		v2 := b.NewValue0(v.Pos, OpZeroExt8to32, typ.UInt32)
 		v2.AddArg(y)
 		v3 := b.NewValue0(v.Pos, OpMIPSMOVWconst, typ.UInt32)
-		v3.AuxInt = int32ToAuxInt(-1)
+		v3.AuxInt = int32ToAuxInt(31)
 		v4 := b.NewValue0(v.Pos, OpMIPSSGTUconst, typ.Bool)
 		v4.AuxInt = int32ToAuxInt(32)
 		v4.AddArg(v2)
@@ -5930,7 +5930,7 @@
 	b := v.Block
 	typ := &b.Func.Config.Types
 	// match: (Rsh32x16 x y)
-	// result: (SRA x ( CMOVZ <typ.UInt32> (ZeroExt16to32 y) (MOVWconst [-1]) (SGTUconst [32] (ZeroExt16to32 y))))
+	// result: (SRA x ( CMOVZ <typ.UInt32> (ZeroExt16to32 y) (MOVWconst [31]) (SGTUconst [32] (ZeroExt16to32 y))))
 	for {
 		x := v_0
 		y := v_1
@@ -5939,7 +5939,7 @@
 		v1 := b.NewValue0(v.Pos, OpZeroExt16to32, typ.UInt32)
 		v1.AddArg(y)
 		v2 := b.NewValue0(v.Pos, OpMIPSMOVWconst, typ.UInt32)
-		v2.AuxInt = int32ToAuxInt(-1)
+		v2.AuxInt = int32ToAuxInt(31)
 		v3 := b.NewValue0(v.Pos, OpMIPSSGTUconst, typ.Bool)
 		v3.AuxInt = int32ToAuxInt(32)
 		v3.AddArg(v1)
@@ -5954,14 +5954,14 @@
 	b := v.Block
 	typ := &b.Func.Config.Types
 	// match: (Rsh32x32 x y)
-	// result: (SRA x ( CMOVZ <typ.UInt32> y (MOVWconst [-1]) (SGTUconst [32] y)))
+	// result: (SRA x ( CMOVZ <typ.UInt32> y (MOVWconst [31]) (SGTUconst [32] y)))
 	for {
 		x := v_0
 		y := v_1
 		v.reset(OpMIPSSRA)
 		v0 := b.NewValue0(v.Pos, OpMIPSCMOVZ, typ.UInt32)
 		v1 := b.NewValue0(v.Pos, OpMIPSMOVWconst, typ.UInt32)
-		v1.AuxInt = int32ToAuxInt(-1)
+		v1.AuxInt = int32ToAuxInt(31)
 		v2 := b.NewValue0(v.Pos, OpMIPSSGTUconst, typ.Bool)
 		v2.AuxInt = int32ToAuxInt(32)
 		v2.AddArg(y)
@@ -6015,7 +6015,7 @@
 	b := v.Block
 	typ := &b.Func.Config.Types
 	// match: (Rsh32x8 x y)
-	// result: (SRA x ( CMOVZ <typ.UInt32> (ZeroExt8to32 y) (MOVWconst [-1]) (SGTUconst [32] (ZeroExt8to32 y))))
+	// result: (SRA x ( CMOVZ <typ.UInt32> (ZeroExt8to32 y) (MOVWconst [31]) (SGTUconst [32] (ZeroExt8to32 y))))
 	for {
 		x := v_0
 		y := v_1
@@ -6024,7 +6024,7 @@
 		v1 := b.NewValue0(v.Pos, OpZeroExt8to32, typ.UInt32)
 		v1.AddArg(y)
 		v2 := b.NewValue0(v.Pos, OpMIPSMOVWconst, typ.UInt32)
-		v2.AuxInt = int32ToAuxInt(-1)
+		v2.AuxInt = int32ToAuxInt(31)
 		v3 := b.NewValue0(v.Pos, OpMIPSSGTUconst, typ.Bool)
 		v3.AuxInt = int32ToAuxInt(32)
 		v3.AddArg(v1)
@@ -6160,7 +6160,7 @@
 	b := v.Block
 	typ := &b.Func.Config.Types
 	// match: (Rsh8x16 x y)
-	// result: (SRA (SignExt16to32 x) ( CMOVZ <typ.UInt32> (ZeroExt16to32 y) (MOVWconst [-1]) (SGTUconst [32] (ZeroExt16to32 y))))
+	// result: (SRA (SignExt16to32 x) ( CMOVZ <typ.UInt32> (ZeroExt16to32 y) (MOVWconst [31]) (SGTUconst [32] (ZeroExt16to32 y))))
 	for {
 		x := v_0
 		y := v_1
@@ -6171,7 +6171,7 @@
 		v2 := b.NewValue0(v.Pos, OpZeroExt16to32, typ.UInt32)
 		v2.AddArg(y)
 		v3 := b.NewValue0(v.Pos, OpMIPSMOVWconst, typ.UInt32)
-		v3.AuxInt = int32ToAuxInt(-1)
+		v3.AuxInt = int32ToAuxInt(31)
 		v4 := b.NewValue0(v.Pos, OpMIPSSGTUconst, typ.Bool)
 		v4.AuxInt = int32ToAuxInt(32)
 		v4.AddArg(v2)
@@ -6186,7 +6186,7 @@
 	b := v.Block
 	typ := &b.Func.Config.Types
 	// match: (Rsh8x32 x y)
-	// result: (SRA (SignExt16to32 x) ( CMOVZ <typ.UInt32> y (MOVWconst [-1]) (SGTUconst [32] y)))
+	// result: (SRA (SignExt16to32 x) ( CMOVZ <typ.UInt32> y (MOVWconst [31]) (SGTUconst [32] y)))
 	for {
 		x := v_0
 		y := v_1
@@ -6195,7 +6195,7 @@
 		v0.AddArg(x)
 		v1 := b.NewValue0(v.Pos, OpMIPSCMOVZ, typ.UInt32)
 		v2 := b.NewValue0(v.Pos, OpMIPSMOVWconst, typ.UInt32)
-		v2.AuxInt = int32ToAuxInt(-1)
+		v2.AuxInt = int32ToAuxInt(31)
 		v3 := b.NewValue0(v.Pos, OpMIPSSGTUconst, typ.Bool)
 		v3.AuxInt = int32ToAuxInt(32)
 		v3.AddArg(y)
@@ -6257,7 +6257,7 @@
 	b := v.Block
 	typ := &b.Func.Config.Types
 	// match: (Rsh8x8 x y)
-	// result: (SRA (SignExt16to32 x) ( CMOVZ <typ.UInt32> (ZeroExt8to32 y) (MOVWconst [-1]) (SGTUconst [32] (ZeroExt8to32 y))))
+	// result: (SRA (SignExt16to32 x) ( CMOVZ <typ.UInt32> (ZeroExt8to32 y) (MOVWconst [31]) (SGTUconst [32] (ZeroExt8to32 y))))
 	for {
 		x := v_0
 		y := v_1
@@ -6268,7 +6268,7 @@
 		v2 := b.NewValue0(v.Pos, OpZeroExt8to32, typ.UInt32)
 		v2.AddArg(y)
 		v3 := b.NewValue0(v.Pos, OpMIPSMOVWconst, typ.UInt32)
-		v3.AuxInt = int32ToAuxInt(-1)
+		v3.AuxInt = int32ToAuxInt(31)
 		v4 := b.NewValue0(v.Pos, OpMIPSSGTUconst, typ.Bool)
 		v4.AuxInt = int32ToAuxInt(32)
 		v4.AddArg(v2)