Merge pull request #3316 from dheaton-arm/implement-uwiden

Implement `UwidenLow` and `UwidenHigh` for the interpreter

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

@@ -0,0 +1,26 @@
+test interpret
+test run
+target aarch64
+set enable_simd
+target x86_64 machinst
+
+function %uwidenhigh_i8x16(i8x16) -> i16x8 {
+block0(v0: i8x16):
+    v1 = uwiden_high v0
+    return v1
+}
+; run: %uwidenhigh_i8x16([1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16]) == [9 10 11 12 13 14 15 16]
+
+function %uwidenhigh_i16x8(i16x8) -> i32x4 {
+block0(v0: i16x8):
+    v1 = uwiden_high v0
+    return v1
+}
+; run: %uwidenhigh_i16x8([1 2 3 4 5 6 7 8]) == [5 6 7 8]
+
+function %uwidenhigh_i32x4(i32x4) -> i64x2 {
+block0(v0: i32x4):
+    v1 = uwiden_high v0
+    return v1
+}
+; run: %uwidenhigh_i32x4([1 2 3 4]) == [3 4]

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

@@ -0,0 +1,26 @@
+test interpret
+test run
+target aarch64
+set enable_simd
+target x86_64 machinst
+
+function %uwidenlow_i8x16(i8x16) -> i16x8 {
+block0(v0: i8x16):
+    v1 = uwiden_low v0
+    return v1
+}
+; run: %uwidenlow_i8x16([1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16]) == [1 2 3 4 5 6 7 8]
+
+function %uwidenlow_i16x8(i16x8) -> i32x4 {
+block0(v0: i16x8):
+    v1 = uwiden_low v0
+    return v1
+}
+; run: %uwidenlow_i16x8([1 2 3 4 5 6 7 8]) == [1 2 3 4]
+
+function %uwidenlow_i32x4(i32x4) -> i64x2 {
+block0(v0: i32x4):
+    v1 = uwiden_low v0
+    return v1
+}
+; run: %uwidenlow_i32x4([1 2 3 4]) == [1 2]