Merge pull request #3008 from afonso360/aarch64-i128-ireduce

aarch64: Implement ireduce for i128 values

cranelift/filetests/filetests/isa/aarch64/reduce.clif

@@ -0,0 +1,43 @@
+test compile
+set unwind_info=false
+target aarch64
+
+function %ireduce_128_64(i128) -> i64 {
+block0(v0: i128):
+  v1 = ireduce.i64 v0
+  return v1
+}
+; check: stp fp, lr, [sp, #-16]!
+; nextln: mov fp, sp
+; nextln: ldp fp, lr, [sp], #16
+; nextln: ret
+
+function %ireduce_128_32(i128) -> i32 {
+block0(v0: i128):
+  v1 = ireduce.i32 v0
+  return v1
+}
+; check: stp fp, lr, [sp, #-16]!
+; nextln: mov fp, sp
+; nextln: ldp fp, lr, [sp], #16
+; nextln: ret
+
+function %ireduce_128_16(i128) -> i16 {
+block0(v0: i128):
+  v1 = ireduce.i16 v0
+  return v1
+}
+; check: stp fp, lr, [sp, #-16]!
+; nextln: mov fp, sp
+; nextln: ldp fp, lr, [sp], #16
+; nextln: ret
+
+function %ireduce_128_8(i128) -> i8 {
+block0(v0: i128):
+  v1 = ireduce.i8 v0
+  return v1
+}
+; check: stp fp, lr, [sp, #-16]!
+; nextln: mov fp, sp
+; nextln: ldp fp, lr, [sp], #16
+; nextln: ret