rust/library/std/tests
Jubilee Young b807d5970b Fold aarch64 feature +fp into +neon
Arm's FEAT_FP and Feat_AdvSIMD describe the same thing on AArch64:
The Neon unit, which handles both floating point and SIMD instructions.
Moreover, a configuration for AArch64 must include both or neither.
Arm says "entirely proprietary" toolchains may omit floating point:
https://developer.arm.com/documentation/102374/0101/Data-processing---floating-point
In the Programmer's Guide for Armv8-A, Arm says AArch64 can have
both FP and Neon or neither in custom implementations:
https://developer.arm.com/documentation/den0024/a/AArch64-Floating-point-and-NEON

In "Bare metal boot code for Armv8-A", enabling Neon and FP
is just disabling the same trap flag:
https://developer.arm.com/documentation/dai0527/a

In an unlikely future where "Neon and FP" become unrelated,
we can add "[+-]fp" as its own feature flag.
Until then, we can simplify programming with Rust on AArch64 by
folding both into "[+-]neon", which is valid as it supersets both.

"[+-]neon" is retained for niche uses such as firmware, kernels,
"I just hate floats", and so on.
2022-03-22 15:14:33 -07:00
..
env.rs Fix SGX CI, take 3 2020-12-07 15:22:34 +01:00
run-time-detect.rs Fold aarch64 feature +fp into +neon 2022-03-22 15:14:33 -07:00
thread.rs