x86: improve bitop code generation with clang

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This uses the new ASM_INPUT_RM macro to avoid the bad code generation
issue that clang has with more generic asm inputs.

This ends up avoiding generating code like this:

 	mov    %r10,(%rsp)
 	tzcnt  (%rsp),%rcx

which now becomes just

 	tzcnt  %r10,%rcx

and in the process ends up also removing a few unnecessary stack frames
when the only use was that pointless "asm uses memory location off stack".

Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

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This commit is contained in:

Linus Torvalds 2024-04-09 11:55:07 -07:00

parent 7453b94851

commit b9b60b3199

1 changed files with 5 additions and 5 deletions

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arch/x86/include/asm/bitops.h

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