[PATCH] D48606: [X86] Use bts/btr/btc for single bit set/clear/complement of a variable bit position

[Roman Lebedev via Phabricator via llvm-commits]

lebedev.ri added a comment.

In https://reviews.llvm.org/D48606#1144023, @craig.topper wrote:

> I'll add the 16-bit tests.
>
> Memory patterns shouldn't be done. BTR/S/C from memory have strange semantics(they don't ignore unused bits of the index) and are really slow because they recompute the memory address using all bits of the index register.


You still probably want some test to document that?

> What do you mean patterns with immediates?

https://godbolt.org/g/GH5p7Z
Unless of course that is also not profitable.


https://reviews.llvm.org/D48606