Re: [PATCH] x86: Optimize variable_test_bit()

From: Vladimir Makarov
Date: Mon May 04 2015 - 14:07:46 EST




On 02/05/15 08:43 AM, Peter Zijlstra wrote:
On Fri, May 01, 2015 at 03:02:24PM -0400, Vladimir Makarov wrote:
Currently LRA is used by x86/x86-64, ARM, AARCH64, s390, and MIPS.
PPC, SH, and ARC are moving to LRA. All other targets are still
reload based.

So I could implement the output reloads in LRA, probably for the
next GCC release. How to enable and mostly use it for multi-target
code like the kernel is another question.
Pretty much all inline asm is in per arch code; so one arch having
different asm features than another should not be a problem at all.
Ok, then. I'll try to implement output operands for asm-goto in LRA for the next GCC release.

Of course, if nobody objects to changing asm goto semantics from

An 'asm goto' statement cannot have outputs ...

to

An 'asm goto' statement cannot have outputs on some targets ...


--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/