cmd/compile: implement constant rotates on arm64

Explicit constant rotates work, but constant arguments to
bits.RotateLeft* needed the additional rule.

Fixes #48465

Change-Id: Ia7544f21d0e7587b6b6506f72421459cd769aea6
Reviewed-on: https://go-review.googlesource.com/c/go/+/350909
Trust: Keith Randall <khr@golang.org>
Trust: Josh Bleecher Snyder <josharian@gmail.com>
Run-TryBot: Keith Randall <khr@golang.org>
TryBot-Result: Go Bot <gobot@golang.org>
Reviewed-by: Josh Bleecher Snyder <josharian@gmail.com>

src/cmd/compile/internal/ssa/gen/ARM.rules

@@ -508,6 +508,8 @@
 (TST x (MOVWconst [c])) => (TSTconst [c] x)
 (TEQ x (MOVWconst [c])) => (TEQconst [c] x)
 
+(SRR x (MOVWconst [c])) => (SRRconst x [c&31])
+
 // Canonicalize the order of arguments to comparisons - helps with CSE.
 (CMP x y) && canonLessThan(x,y) => (InvertFlags (CMP y x))
 
@@ -1136,7 +1138,6 @@
 ( ORshiftRL [c] (SLLconst x [32-c]) x) => (SRRconst [   c] x)
 (XORshiftRL [c] (SLLconst x [32-c]) x) => (SRRconst [   c] x)
 
-(RotateLeft32 x (MOVWconst [c])) => (SRRconst [-c&31] x)
 (RotateLeft16 <t> x (MOVWconst [c])) => (Or16 (Lsh16x32 <t> x (MOVWconst [c&15])) (Rsh16Ux32 <t> x (MOVWconst [-c&15])))
 (RotateLeft8 <t> x (MOVWconst [c])) => (Or8 (Lsh8x32 <t> x (MOVWconst [c&7])) (Rsh8Ux32 <t> x (MOVWconst [-c&7])))
 (RotateLeft32 x y) => (SRR x (RSBconst [0] <y.Type> y))

src/cmd/compile/internal/ssa/gen/ARM64.rules

@@ -1175,6 +1175,9 @@
 (CMPW x (MOVDconst [c])) => (CMPWconst [int32(c)] x)
 (CMPW (MOVDconst [c]) x) => (InvertFlags (CMPWconst [int32(c)] x))
 
+(ROR x (MOVDconst [c])) => (RORconst x [c&63])
+(RORW x (MOVDconst [c])) => (RORWconst x [c&31])
+
 // Canonicalize the order of arguments to comparisons - helps with CSE.
 ((CMP|CMPW) x y) && canonLessThan(x,y) => (InvertFlags ((CMP|CMPW) y x))
 

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

@@ -338,6 +338,8 @@ func rewriteValueARM(v *Value) bool {
 		return rewriteValueARM_OpARMSRL(v)
 	case OpARMSRLconst:
 		return rewriteValueARM_OpARMSRLconst(v)
+	case OpARMSRR:
+		return rewriteValueARM_OpARMSRR(v)
 	case OpARMSUB:
 		return rewriteValueARM_OpARMSUB(v)
 	case OpARMSUBD:
@@ -10523,6 +10525,24 @@ func rewriteValueARM_OpARMSRLconst(v *Value) bool {
 	}
 	return false
 }
+func rewriteValueARM_OpARMSRR(v *Value) bool {
+	v_1 := v.Args[1]
+	v_0 := v.Args[0]
+	// match: (SRR x (MOVWconst [c]))
+	// result: (SRRconst x [c&31])
+	for {
+		x := v_0
+		if v_1.Op != OpARMMOVWconst {
+			break
+		}
+		c := auxIntToInt32(v_1.AuxInt)
+		v.reset(OpARMSRRconst)
+		v.AuxInt = int32ToAuxInt(c & 31)
+		v.AddArg(x)
+		return true
+	}
+	return false
+}
 func rewriteValueARM_OpARMSUB(v *Value) bool {
 	v_1 := v.Args[1]
 	v_0 := v.Args[0]
@@ -14904,19 +14924,6 @@ func rewriteValueARM_OpRotateLeft32(v *Value) bool {
 	v_1 := v.Args[1]
 	v_0 := v.Args[0]
 	b := v.Block
-	// match: (RotateLeft32 x (MOVWconst [c]))
-	// result: (SRRconst [-c&31] x)
-	for {
-		x := v_0
-		if v_1.Op != OpARMMOVWconst {
-			break
-		}
-		c := auxIntToInt32(v_1.AuxInt)
-		v.reset(OpARMSRRconst)
-		v.AuxInt = int32ToAuxInt(-c & 31)
-		v.AddArg(x)
-		return true
-	}
 	// match: (RotateLeft32 x y)
 	// result: (SRR x (RSBconst [0] <y.Type> y))
 	for {

src/cmd/compile/internal/ssa/rewriteARM64.go

@@ -323,6 +323,10 @@ func rewriteValueARM64(v *Value) bool {
 		return rewriteValueARM64_OpARM64ORshiftRA(v)
 	case OpARM64ORshiftRL:
 		return rewriteValueARM64_OpARM64ORshiftRL(v)
+	case OpARM64ROR:
+		return rewriteValueARM64_OpARM64ROR(v)
+	case OpARM64RORW:
+		return rewriteValueARM64_OpARM64RORW(v)
 	case OpARM64RORWconst:
 		return rewriteValueARM64_OpARM64RORWconst(v)
 	case OpARM64RORconst:
@@ -19956,6 +19960,42 @@ func rewriteValueARM64_OpARM64ORshiftRL(v *Value) bool {
 	}
 	return false
 }
+func rewriteValueARM64_OpARM64ROR(v *Value) bool {
+	v_1 := v.Args[1]
+	v_0 := v.Args[0]
+	// match: (ROR x (MOVDconst [c]))
+	// result: (RORconst x [c&63])
+	for {
+		x := v_0
+		if v_1.Op != OpARM64MOVDconst {
+			break
+		}
+		c := auxIntToInt64(v_1.AuxInt)
+		v.reset(OpARM64RORconst)
+		v.AuxInt = int64ToAuxInt(c & 63)
+		v.AddArg(x)
+		return true
+	}
+	return false
+}
+func rewriteValueARM64_OpARM64RORW(v *Value) bool {
+	v_1 := v.Args[1]
+	v_0 := v.Args[0]
+	// match: (RORW x (MOVDconst [c]))
+	// result: (RORWconst x [c&31])
+	for {
+		x := v_0
+		if v_1.Op != OpARM64MOVDconst {
+			break
+		}
+		c := auxIntToInt64(v_1.AuxInt)
+		v.reset(OpARM64RORWconst)
+		v.AuxInt = int64ToAuxInt(c & 31)
+		v.AddArg(x)
+		return true
+	}
+	return false
+}
 func rewriteValueARM64_OpARM64RORWconst(v *Value) bool {
 	v_0 := v.Args[0]
 	// match: (RORWconst [c] (RORWconst [d] x))

test/codegen/rotate.go

@@ -34,8 +34,15 @@ func rot64(x uint64) uint64 {
 	// ppc64le:"ROTL\t[$]9"
 	a += x<<9 ^ x>>55
 
-	// s390x:"RISBGZ\t[$]0, [$]63, [$]7, "
+	// amd64:"ROLQ\t[$]10"
+	// arm64:"ROR\t[$]54"
+	// s390x:"RISBGZ\t[$]0, [$]63, [$]10, "
+	// ppc64:"ROTL\t[$]10"
+	// ppc64le:"ROTL\t[$]10"
 	// arm64:"ROR\t[$]57" // TODO this is not great line numbering, but then again, the instruction did appear
+	// s390x:"RISBGZ\t[$]0, [$]63, [$]7, " // TODO ditto
+	a += bits.RotateLeft64(x, 10)
+
 	return a
 }
 
@@ -64,8 +71,16 @@ func rot32(x uint32) uint32 {
 	// ppc64le:"ROTLW\t[$]9"
 	a += x<<9 ^ x>>23
 
-	// s390x:"RLL\t[$]7"
+	// amd64:"ROLL\t[$]10"
+	// arm:"MOVW\tR\\d+@>22"
+	// arm64:"RORW\t[$]22"
+	// s390x:"RLL\t[$]10"
+	// ppc64:"ROTLW\t[$]10"
+	// ppc64le:"ROTLW\t[$]10"
 	// arm64:"RORW\t[$]25" // TODO this is not great line numbering, but then again, the instruction did appear
+	// s390x:"RLL\t[$]7" // TODO ditto
+	a += bits.RotateLeft32(x, 10)
+
 	return a
 }