machinst x64: fix generation of RegMemImm immediate operands;
@@ -175,11 +175,11 @@ fn input_to_reg_mem(ctx: Ctx, spec: InsnInput) -> RegMem {
/// TODO: handle memory as well!
fn input_to_reg_mem_imm(ctx: Ctx, spec: InsnInput) -> RegMemImm {
let imm = ctx.get_input(spec.insn, spec.input).constant.and_then(|x| {
- let as_u32 = x as u32;
- let extended = as_u32 as u64;
- // If the truncation and sign-extension don't change the value, use it.
- if extended == x {
- Some(as_u32)
+ // For i64 instructions (prefixed with REX.W), require that the immediate will sign-extend
+ // to 64 bits. For other sizes, it doesn't matter and we can just use the plain
+ // constant.
+ if ctx.input_ty(spec.insn, spec.input).bytes() != 8 || low32_will_sign_extend_to_64(x) {
+ Some(x as u32)
} else {
None
}
