| Issue |
75956
|
| Summary |
[libc] LIBC_INLINE_ASM pessimizes asm statements that are not implicitly volatile
|
| Labels |
libc
|
| Assignees |
|
| Reporter |
nickdesaulniers
|
why do we have LIBC_INLINE_ASM? Throwing volatile on every asm is a pessimization. It generally prevents CSE which is bad.
> asm statements that have no output operands and asm goto statements, are implicitly volatile.
https://gcc.gnu.org/onlinedocs/gcc/Extended-Asm.html#Volatile
We're pretty inconsistent in our use of `asm` vs `__asm__` (and same with `__volatile__`). We should clean all that up and just use `asm` then explicitly mark cases where we need `volatile`.
Putting volatile around everything is great for avoiding compiler bugs from 20 year old compilers, which we don't support.
Putting __ prefix+suffix also doesn't seem necessary.
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