`evaluation of constant value failed` on nightly

[Herschel]

rustfft fails to build on rustc nightly for 05/09 and later:

cargo test

error[E0080]: evaluation of constant value failed
 --> C:\Users\x\.rustup\toolchains\nightly-x86_64-pc-windows-msvc\lib/rustlib/src/rust\library\core\src\..\..\stdarch\crates\core_arch\src\macros.rs:8:17
  |
8 |         let _ = 1 / ((IMM >= MIN && IMM <= MAX) as usize);
  |                 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ attempt to divide `1_usize` by zero

It is hitting this faux static assert in std::arch:
https://github.com/rust-lang/stdarch/blob/master/crates/core_arch/src/macros.rs#L5-L10
probably becomes one of the SIMD calls is passing an out-of-range value. This unfortunately affects downstream crates that depend on rustfft.

D:\projects\RustFFT>rustc -V
rustc 1.54.0-nightly (ca82264ec 2021-05-09)

[ejmahler]

RustFFT 6.0.1 has peen published, which fixes this issue. Thanks Herschel for reporting, and thanks to Henrik Enquist for fixing.

[ejmahler]

I have also backported this to a version 5.1.1

[Herschel]

Thank you for the very prompt fix!