Code
I tried this code:
pub fn reg_name(x: RegisterNo) -> &'static str {
NAME[x as usize]
}
const NAME: [&'static str; 8] = [
"al", "cl", "dl", "bl",
"ah", "ch", "dh", "bh"
];
#[repr(i8)]
pub enum RegisterNo {
AL = 0,
CL = 1,
DL = 2,
BL = 3,
AH = 4,
CH = 5,
DH = 6,
BH = 7,
}I expected to see this happen: all range checks would be eliminated and function would be panic-free.
Instead, this happened: range checks are still there and function is no longer panic-free.
Version it worked on
It most recently worked on: 1.63
Version with regression
rustc --version --verbose:
rustc 1.64.0 (a55dd71d5 2022-09-19)
binary: rustc
commit-hash: a55dd71d5fb0ec5a6a3a9e8c27b2127ba491ce52
commit-date: 2022-09-19
host: x86_64-unknown-linux-gnu
release: 1.64.0
LLVM version: 14.0.6
Workaround that currently works is to use NAME[x as usize & 0x7].
But this seems strange, wrong, and shouldn't be necessary (it worked in the past!).
Code
I tried this code:
I expected to see this happen: all range checks would be eliminated and function would be panic-free.
Instead, this happened: range checks are still there and function is no longer panic-free.
Version it worked on
It most recently worked on: 1.63
Version with regression
rustc --version --verbose:Workaround that currently works is to use
NAME[x as usize & 0x7].But this seems strange, wrong, and shouldn't be necessary (it worked in the past!).