diff --git a/src/cmd/compile/internal/ssa/gen/RISCV64.rules b/src/cmd/compile/internal/ssa/gen/RISCV64.rules
index fd5bfd36c6..e37c7b7899 100644
--- a/src/cmd/compile/internal/ssa/gen/RISCV64.rules
+++ b/src/cmd/compile/internal/ssa/gen/RISCV64.rules
@@ -697,6 +697,16 @@
 (MOVBUreg x:(Select0 (LoweredAtomicCas32 _ _ _ _))) => (MOVDreg x)
 (MOVBUreg x:(Select0 (LoweredAtomicCas64 _ _ _ _))) => (MOVDreg x)
 
+// Avoid sign extension after word arithmetic.
+(MOVWreg x:(ADDIW   _)) => (MOVDreg x)
+(MOVWreg x:(SUBW  _ _)) => (MOVDreg x)
+(MOVWreg x:(NEGW    _)) => (MOVDreg x)
+(MOVWreg x:(MULW  _ _)) => (MOVDreg x)
+(MOVWreg x:(DIVW  _ _)) => (MOVDreg x)
+(MOVWreg x:(DIVUW _ _)) => (MOVDreg x)
+(MOVWreg x:(REMW  _ _)) => (MOVDreg x)
+(MOVWreg x:(REMUW _ _)) => (MOVDreg x)
+
 // Fold double extensions.
 (MOVBreg  x:(MOVBreg  _)) => (MOVDreg x)
 (MOVHreg  x:(MOVBreg  _)) => (MOVDreg x)
diff --git a/src/cmd/compile/internal/ssa/rewriteRISCV64.go b/src/cmd/compile/internal/ssa/rewriteRISCV64.go
index 66b729f046..6f949707a1 100644
--- a/src/cmd/compile/internal/ssa/rewriteRISCV64.go
+++ b/src/cmd/compile/internal/ssa/rewriteRISCV64.go
@@ -5027,6 +5027,94 @@ func rewriteValueRISCV64_OpRISCV64MOVWreg(v *Value) bool {
 		v.AddArg(x)
 		return true
 	}
+	// match: (MOVWreg x:(ADDIW _))
+	// result: (MOVDreg x)
+	for {
+		x := v_0
+		if x.Op != OpRISCV64ADDIW {
+			break
+		}
+		v.reset(OpRISCV64MOVDreg)
+		v.AddArg(x)
+		return true
+	}
+	// match: (MOVWreg x:(SUBW _ _))
+	// result: (MOVDreg x)
+	for {
+		x := v_0
+		if x.Op != OpRISCV64SUBW {
+			break
+		}
+		v.reset(OpRISCV64MOVDreg)
+		v.AddArg(x)
+		return true
+	}
+	// match: (MOVWreg x:(NEGW _))
+	// result: (MOVDreg x)
+	for {
+		x := v_0
+		if x.Op != OpRISCV64NEGW {
+			break
+		}
+		v.reset(OpRISCV64MOVDreg)
+		v.AddArg(x)
+		return true
+	}
+	// match: (MOVWreg x:(MULW _ _))
+	// result: (MOVDreg x)
+	for {
+		x := v_0
+		if x.Op != OpRISCV64MULW {
+			break
+		}
+		v.reset(OpRISCV64MOVDreg)
+		v.AddArg(x)
+		return true
+	}
+	// match: (MOVWreg x:(DIVW _ _))
+	// result: (MOVDreg x)
+	for {
+		x := v_0
+		if x.Op != OpRISCV64DIVW {
+			break
+		}
+		v.reset(OpRISCV64MOVDreg)
+		v.AddArg(x)
+		return true
+	}
+	// match: (MOVWreg x:(DIVUW _ _))
+	// result: (MOVDreg x)
+	for {
+		x := v_0
+		if x.Op != OpRISCV64DIVUW {
+			break
+		}
+		v.reset(OpRISCV64MOVDreg)
+		v.AddArg(x)
+		return true
+	}
+	// match: (MOVWreg x:(REMW _ _))
+	// result: (MOVDreg x)
+	for {
+		x := v_0
+		if x.Op != OpRISCV64REMW {
+			break
+		}
+		v.reset(OpRISCV64MOVDreg)
+		v.AddArg(x)
+		return true
+	}
+	// match: (MOVWreg x:(REMUW _ _))
+	// result: (MOVDreg x)
+	for {
+		x := v_0
+		if x.Op != OpRISCV64REMUW {
+			break
+		}
+		v.reset(OpRISCV64MOVDreg)
+		v.AddArg(x)
+		return true
+	}
 	// match: (MOVWreg x:(MOVBreg _))
 	// result: (MOVDreg x)
 	for {