diff --git a/cranelift/codegen/meta/src/shared/instructions.rs b/cranelift/codegen/meta/src/shared/instructions.rs
index 955782039d..0bbaa2907b 100644
--- a/cranelift/codegen/meta/src/shared/instructions.rs
+++ b/cranelift/codegen/meta/src/shared/instructions.rs
@@ -2469,8 +2469,7 @@ pub(crate) fn define(
         Signed integer multiplication, producing the high half of a
         double-length result.
 
-        Polymorphic over all scalar integer types, but does not support vector
-        types.
+        Polymorphic over all integer types (vector and scalar).
         "#,
             &formats.binary,
         )
diff --git a/cranelift/filetests/filetests/runtests/simd-smulhi.clif b/cranelift/filetests/filetests/runtests/simd-smulhi.clif
new file mode 100644
index 0000000000..5fc0445bb4
--- /dev/null
+++ b/cranelift/filetests/filetests/runtests/simd-smulhi.clif
@@ -0,0 +1,30 @@
+test interpret
+; The AArch64 and x86_64 backends only support scalar values.
+
+function %smulhi_i8x16(i8x16, i8x16) -> i8x16 {
+block0(v0: i8x16, v1: i8x16):
+    v2 = smulhi v0, v1
+    return v2
+}
+; run: %smulhi_i8x16([1 -2 3 -4 5 -6 7 -8 127 127 127 127 -128 -128 -128 -128], [9 10 -11 -12 13 14 -15 -16 17 18 -19 -20 21 22 -128 127]) == [0 -1 -1 0 0 -1 -1 0 8 8 -10 -10 -11 -11 64 -64]
+
+function %smulhi_i16x8(i16x8, i16x8) -> i16x8 {
+block0(v0: i16x8, v1: i16x8):
+    v2 = smulhi v0, v1
+    return v2
+}
+; run: %smulhi_i16x8([1 -2 255 -255 255 -255 32767 -32768], [3 4 -5 -6 7 8 -32768 -32768]) == [0 -1 -1 0 0 -1 -16384 16384]
+
+function %smulhi_i32x4(i32x4, i32x4) -> i32x4 {
+block0(v0: i32x4, v1: i32x4):
+    v2 = smulhi v0, v1
+    return v2
+}
+; run: %smulhi_i32x4([1 -255 65535 -2147483648], [2 65535 -2147483647 -2147483647]) == [0 -1 -32768 1073741823]
+
+function %smulhi_i64x2(i64x2, i64x2) -> i64x2 {
+block0(v0: i64x2, v1: i64x2):
+    v2 = smulhi v0, v1
+    return v2
+}
+; run: %smulhi_i64x2([-1 9223372036854775807], [-2 -9223372036854775808]) == [0 -4611686018427387904]
\ No newline at end of file
diff --git a/cranelift/filetests/filetests/runtests/smulhi-aarch64.clif b/cranelift/filetests/filetests/runtests/smulhi-aarch64.clif
new file mode 100644
index 0000000000..b123f2f0c9
--- /dev/null
+++ b/cranelift/filetests/filetests/runtests/smulhi-aarch64.clif
@@ -0,0 +1,13 @@
+test interpret
+test run
+target aarch64
+; x86_64 backend only supports `i16`, `i32`, and `i64` types.
+
+function %smulhi_i8(i8, i8) -> i8 {
+block0(v0: i8, v1: i8):
+    v2 = smulhi v0, v1
+    return v2
+}
+; run: %smulhi_i8(-2, -4) == 0
+; run: %smulhi_i8(2, -4) == -1
+; run: %smulhi_i8(127, 127) == 63
\ No newline at end of file
diff --git a/cranelift/filetests/filetests/runtests/smulhi.clif b/cranelift/filetests/filetests/runtests/smulhi.clif
new file mode 100644
index 0000000000..b2fe1072ed
--- /dev/null
+++ b/cranelift/filetests/filetests/runtests/smulhi.clif
@@ -0,0 +1,32 @@
+test interpret
+test run
+target aarch64
+set enable_simd
+target x86_64 machinst
+
+function %smulhi_i16(i16, i16) -> i16 {
+block0(v0: i16, v1: i16):
+    v2 = smulhi v0, v1
+    return v2
+}
+; run: %smulhi_i16(-2, -4) == 0
+; run: %smulhi_i16(2, -4) == -1
+; run: %smulhi_i16(32767, 32767) == 16383
+
+function %smulhi_i32(i32, i32) -> i32 {
+block0(v0: i32, v1: i32):
+    v2 = smulhi v0, v1
+    return v2
+}
+; run: %smulhi_i32(-500, -700) == 0
+; run: %smulhi_i32(500, -700) == -1
+; run: %smulhi_i32(2147483647, 2147483647) == 1073741823
+
+function %smulhi_i64(i64, i64) -> i64 {
+block0(v0: i64, v1: i64):
+    v2 = smulhi v0, v1
+    return v2
+}
+; run: %smulhi_i64(-4294967295, -4294967295) == 0
+; run: %smulhi_i64(4294967295, -4294967295) == -1
+; run: %smulhi_i64(9223372036854775807, 9223372036854775807) == 4611686018427387903
diff --git a/cranelift/interpreter/src/step.rs b/cranelift/interpreter/src/step.rs
index 25ec8b2878..cff3c32f2a 100644
--- a/cranelift/interpreter/src/step.rs
+++ b/cranelift/interpreter/src/step.rs
@@ -553,15 +553,20 @@ where
         Opcode::Ineg => binary(Value::sub, Value::int(0, ctrl_ty)?, arg(0)?)?,
         Opcode::Iabs => unimplemented!("Iabs"),
         Opcode::Imul => binary(Value::mul, arg(0)?, arg(1)?)?,
-        Opcode::Umulhi => {
+        Opcode::Umulhi | Opcode::Smulhi => {
+            let double_length = match ctrl_ty.lane_bits() {
+                8 => types::I16,
+                16 => types::I32,
+                32 => types::I64,
+                64 => types::I128,
+                _ => unimplemented!("Unsupported integer length {}", ctrl_ty.bits()),
+            };
+            let conv_type = if inst.opcode() == Opcode::Umulhi {
+                ValueConversionKind::ZeroExtend(double_length)
+            } else {
+                ValueConversionKind::SignExtend(double_length)
+            };
             if ctrl_ty.is_vector() {
-                let double_length = match ctrl_ty.lane_bits() {
-                    8 => types::I16,
-                    16 => types::I32,
-                    32 => types::I64,
-                    64 => types::I128,
-                    _ => unimplemented!("Unsupported integer length {}", ctrl_ty.bits()),
-                };
                 let arg0 = extractlanes(&arg(0)?, ctrl_ty.lane_type())?;
                 let arg1 = extractlanes(&arg(1)?, ctrl_ty.lane_type())?;
 
@@ -569,8 +574,8 @@ where
                     .into_iter()
                     .zip(arg1)
                     .map(|(x, y)| {
-                        let x = x.convert(ValueConversionKind::ZeroExtend(double_length))?;
-                        let y = y.convert(ValueConversionKind::ZeroExtend(double_length))?;
+                        let x = x.convert(conv_type.clone())?;
+                        let y = y.convert(conv_type.clone())?;
 
                         Ok(Value::mul(x, y)?
                             .convert(ValueConversionKind::ExtractUpper(ctrl_ty.lane_type()))?)
@@ -579,30 +584,12 @@ where
 
                 assign(vectorizelanes(&res, ctrl_ty)?)
             } else {
-                let double_length = match ctrl_ty.bits() {
-                    8 => types::I16,
-                    16 => types::I32,
-                    32 => types::I64,
-                    64 => types::I128,
-                    _ => unimplemented!("Unsupported integer length {}", ctrl_ty.bits()),
-                };
-                let x: V = Value::int(
-                    arg(0)?
-                        .convert(ValueConversionKind::ToUnsigned)?
-                        .into_int()?,
-                    double_length,
-                )?;
-                let y: V = Value::int(
-                    arg(1)?
-                        .convert(ValueConversionKind::ToUnsigned)?
-                        .into_int()?,
-                    double_length,
-                )?;
+                let x: V = arg(0)?.convert(conv_type.clone())?;
+                let y: V = arg(1)?.convert(conv_type.clone())?;
                 let z = Value::mul(x, y)?.convert(ValueConversionKind::ExtractUpper(ctrl_ty))?;
                 assign(z)
             }
         }
-        Opcode::Smulhi => unimplemented!("Smulhi"),
         Opcode::Udiv => binary_unsigned_can_trap(Value::div, arg(0)?, arg(1)?)?,
         Opcode::Sdiv => binary_can_trap(Value::div, arg(0)?, arg(1)?)?,
         Opcode::Urem => binary_unsigned_can_trap(Value::rem, arg(0)?, arg(1)?)?,
diff --git a/cranelift/interpreter/src/value.rs b/cranelift/interpreter/src/value.rs
index 768ccfe8e2..13d28d5156 100644
--- a/cranelift/interpreter/src/value.rs
+++ b/cranelift/interpreter/src/value.rs
@@ -308,6 +308,7 @@ impl Value for DataValue {
                 (DataValue::I16(n), types::I32) => DataValue::I32(n as i32),
                 (DataValue::I16(n), types::I64) => DataValue::I64(n as i64),
                 (DataValue::I32(n), types::I64) => DataValue::I64(n as i64),
+                (DataValue::I64(n), types::I128) => DataValue::I128(n as i128),
                 (dv, _) => unimplemented!("conversion: {} -> {:?}", dv.ty(), kind),
             },
             ValueConversionKind::ZeroExtend(ty) => match (self, ty) {