test regalloc
isa x86

; %rdi can't be used in a movsbl instruction, so test that the register
; allocator can move it to a register that can be.

function %test(i32 [%rdi]) -> i32 system_v {
ebb0(v0: i32 [%rdi]):
    v1 = ireduce.i8 v0
    v2 = sextend.i32 v1
    return v2
}
; check: regmove v1, %rdi -> %rax