Implement vsplit in cranelift interpreter (bytecodealliance#5462)

* Add vsplit testfile

* Add vsplit implementation

Author: MozarellaMan

cranelift/filetests/filetests/runtests/simd-vsplit.clif

@@ -0,0 +1,31 @@
+test interpret
+
+function %vsplit_i32x4_hi(i32x4) -> i32x2 {
+block0(v0: i32x4):
+    v1, v2 = vsplit.i32x4 v0
+    return v1
+}
+; run: %vsplit_i32x4_hi([1 2 3 4]) == [1 2]
+
+function %vsplit_i32x4_lo(i32x4) -> i32x2 {
+block0(v0: i32x4):
+    v1, v2 = vsplit.i32x4 v0
+    return v2
+}
+; run: %vsplit_i32x4_lo([1 2 3 4]) == [3 4]
+
+
+
+function %vsplit_scalar_i64x2_hi(i64x2) -> i64 {
+block0(v0: i64x2):
+    v1, v2 = vsplit.i64x2 v0
+    return v1
+}
+; run: %vsplit_scalar_i64x2_hi([1 2]) == 1
+
+function %vsplit_scalar_i64x2_lo(i64x2) -> i64 {
+block0(v0: i64x2):
+    v1, v2 = vsplit.i64x2 v0
+    return v2
+}
+; run: %vsplit_scalar_i64x2_lo([3 4]) == 4

cranelift/interpreter/src/step.rs

@@ -985,7 +985,15 @@ where
             }
             assign(Value::int(result, ctrl_ty)?)
         }
-        Opcode::Vsplit => unimplemented!("Vsplit"),
+        Opcode::Vsplit => {
+            let new_type = ctrl_ty.half_vector().unwrap();
+            let vector = extractlanes(&arg(0)?, ctrl_ty)?;
+            let (high, low) = vector.split_at((ctrl_ty.lane_count() / 2) as usize);
+            assign_multiple(&[
+                vectorizelanes(high, new_type)?,
+                vectorizelanes(low, new_type)?,
+            ])
+        }
         Opcode::Vconcat => unimplemented!("Vconcat"),
         Opcode::Vselect => assign(vselect(&arg(0)?, &arg(1)?, &arg(2)?, ctrl_ty)?),
         Opcode::VanyTrue => {