1 files changed, 68 insertions, 0 deletions
diff --git a/src/cmd/compile/internal/ssa/rewriteARM64.go b/src/cmd/compile/internal/ssa/rewriteARM64.go
index 7cc7a2a424..a43a366c67 100644
--- a/src/cmd/compile/internal/ssa/rewriteARM64.go
+++ b/src/cmd/compile/internal/ssa/rewriteARM64.go
@@ -8271,6 +8271,25 @@ func rewriteValueARM64_OpARM64MOVBreg(v *Value) bool {
 		v.AuxInt = int64ToAuxInt(int64(int8(c)))
 		return true
 	}
+	// match: (MOVBreg <t> (ANDconst x [c]))
+	// cond: uint64(c) & uint64(0xffffffffffffff80) == 0
+	// result: (ANDconst <t> x [c])
+	for {
+		t := v.Type
+		if v_0.Op != OpARM64ANDconst {
+			break
+		}
+		c := auxIntToInt64(v_0.AuxInt)
+		x := v_0.Args[0]
+		if !(uint64(c)&uint64(0xffffffffffffff80) == 0) {
+			break
+		}
+		v.reset(OpARM64ANDconst)
+		v.Type = t
+		v.AuxInt = int64ToAuxInt(c)
+		v.AddArg(x)
+		return true
+	}
 	// match: (MOVBreg (SLLconst [lc] x))
 	// cond: lc < 8
 	// result: (SBFIZ [armBFAuxInt(lc, 8-lc)] x)
@@ -11991,6 +12010,25 @@ func rewriteValueARM64_OpARM64MOVHreg(v *Value) bool {
 		v.AuxInt = int64ToAuxInt(int64(int16(c)))
 		return true
 	}
+	// match: (MOVHreg <t> (ANDconst x [c]))
+	// cond: uint64(c) & uint64(0xffffffffffff8000) == 0
+	// result: (ANDconst <t> x [c])
+	for {
+		t := v.Type
+		if v_0.Op != OpARM64ANDconst {
+			break
+		}
+		c := auxIntToInt64(v_0.AuxInt)
+		x := v_0.Args[0]
+		if !(uint64(c)&uint64(0xffffffffffff8000) == 0) {
+			break
+		}
+		v.reset(OpARM64ANDconst)
+		v.Type = t
+		v.AuxInt = int64ToAuxInt(c)
+		v.AddArg(x)
+		return true
+	}
 	// match: (MOVHreg (SLLconst [lc] x))
 	// cond: lc < 16
 	// result: (SBFIZ [armBFAuxInt(lc, 16-lc)] x)
@@ -13687,6 +13725,17 @@ func rewriteValueARM64_OpARM64MOVWUreg(v *Value) bool {
 		v.AuxInt = int64ToAuxInt(int64(uint32(c)))
 		return true
 	}
+	// match: (MOVWUreg x)
+	// cond: zeroUpper32Bits(x, 3)
+	// result: x
+	for {
+		x := v_0
+		if !(zeroUpper32Bits(x, 3)) {
+			break
+		}
+		v.copyOf(x)
+		return true
+	}
 	// match: (MOVWUreg (SLLconst [lc] x))
 	// cond: lc >= 32
 	// result: (MOVDconst [0])
@@ -14189,6 +14238,25 @@ func rewriteValueARM64_OpARM64MOVWreg(v *Value) bool {
 		v.AuxInt = int64ToAuxInt(int64(int32(c)))
 		return true
 	}
+	// match: (MOVWreg <t> (ANDconst x [c]))
+	// cond: uint64(c) & uint64(0xffffffff80000000) == 0
+	// result: (ANDconst <t> x [c])
+	for {
+		t := v.Type
+		if v_0.Op != OpARM64ANDconst {
+			break
+		}
+		c := auxIntToInt64(v_0.AuxInt)
+		x := v_0.Args[0]
+		if !(uint64(c)&uint64(0xffffffff80000000) == 0) {
+			break
+		}
+		v.reset(OpARM64ANDconst)
+		v.Type = t
+		v.AuxInt = int64ToAuxInt(c)
+		v.AddArg(x)
+		return true
+	}
 	// match: (MOVWreg (SLLconst [lc] x))
 	// cond: lc < 32
 	// result: (SBFIZ [armBFAuxInt(lc, 32-lc)] x)