[compiler-rt] [compiler-rt][ARM] Optimized f32 add/subtract for Armv6-M. (PR #154093)

[Peter Smith via llvm-commits]

https://github.com/smithp35 commented:

A disclaimer that I was involved in the internal review for Arm Optimized Routines, and on principle I'm in favour of this change. I've concentrated on the parts unique to compiler-rt.

Do you happen to have a figure for code-size? One possible objection is someone preferring a smallest possible implementation for M0 at the expense of performance. Obviously can't just compare the length of the file as that contains comments, and instructions can be 2 or 4 bytes. To be clear I'm not advocating for an additional choice of routine based on size/performance.

Presumably the denormal issue you found was unique to the existing Arm assembly implementation and not the general C implementation (otherwise the tests would fail on non v6-m platforms)?

https://github.com/llvm/llvm-project/pull/154093