aarch64: Implement lowering uextend/sextend for i128 values

cranelift/filetests/filetests/isa/aarch64/extend-op.clif

@@ -16,3 +16,109 @@ block0(v0: i8):
 ; nextln:  add x0, x1, x0, SXTB
 ; nextln:  ldp fp, lr, [sp], #16
 ; nextln:  ret
+
+
+function %i128_uextend_i64(i64) -> i128 {
+block0(v0: i64):
+    v1 = uextend.i128 v0
+    return v1
+}
+
+; check: stp fp, lr, [sp, #-16]!
+; nextln: mov fp, sp
+; nextln: movz x1, #0
+; nextln: ldp fp, lr, [sp], #16
+; nextln: ret
+
+function %i128_sextend_i64(i64) -> i128 {
+block0(v0: i64):
+    v1 = sextend.i128 v0
+    return v1
+}
+
+; check: stp fp, lr, [sp, #-16]!
+; nextln: mov fp, sp
+; nextln: asr x1, x0, #63
+; nextln: ldp fp, lr, [sp], #16
+; nextln: ret
+
+
+function %i128_uextend_i32(i32) -> i128 {
+block0(v0: i32):
+    v1 = uextend.i128 v0
+    return v1
+}
+
+; check: stp fp, lr, [sp, #-16]!
+; nextln: mov fp, sp
+; nextln: mov w0, w0
+; nextln: movz x1, #0
+; nextln: ldp fp, lr, [sp], #16
+; nextln: ret
+
+function %i128_sextend_i32(i32) -> i128 {
+block0(v0: i32):
+    v1 = sextend.i128 v0
+    return v1
+}
+
+; check: stp fp, lr, [sp, #-16]!
+; nextln: mov fp, sp
+; nextln: sxtw x0, w0
+; nextln: asr x1, x0, #63
+; nextln: ldp fp, lr, [sp], #16
+; nextln: ret
+
+
+function %i128_uextend_i16(i16) -> i128 {
+block0(v0: i16):
+    v1 = uextend.i128 v0
+    return v1
+}
+
+; check: stp fp, lr, [sp, #-16]!
+; nextln: mov fp, sp
+; nextln: uxth w0, w0
+; nextln: movz x1, #0
+; nextln: ldp fp, lr, [sp], #16
+; nextln: ret
+
+function %i128_sextend_i16(i16) -> i128 {
+block0(v0: i16):
+    v1 = sextend.i128 v0
+    return v1
+}
+
+; check: stp fp, lr, [sp, #-16]!
+; nextln: mov fp, sp
+; nextln: sxth x0, w0
+; nextln: asr x1, x0, #63
+; nextln: ldp fp, lr, [sp], #16
+; nextln: ret
+
+
+function %i128_uextend_i8(i8) -> i128 {
+block0(v0: i8):
+    v1 = uextend.i128 v0
+    return v1
+}
+
+; check: stp fp, lr, [sp, #-16]!
+; nextln: mov fp, sp
+; nextln: uxtb w0, w0
+; nextln: movz x1, #0
+; nextln: ldp fp, lr, [sp], #16
+; nextln: ret
+
+function %i128_sextend_i8(i8) -> i128 {
+block0(v0: i8):
+    v1 = sextend.i128 v0
+    return v1
+}
+
+; check: stp fp, lr, [sp, #-16]!
+; nextln: mov fp, sp
+; nextln: sxtb x0, w0
+; nextln: asr x1, x0, #63
+; nextln: ldp fp, lr, [sp], #16
+; nextln: ret