Re: PROPOSAL: Extend inline asm syntax with size spec

* Segher Boessenkool [off-list ref] wrote:

On Mon, Oct 08, 2018 at 11:07:46AM +0200, Richard Biener wrote:

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On Mon, 8 Oct 2018, Segher Boessenkool wrote:

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On Sun, Oct 07, 2018 at 03:53:26PM +0000, Michael Matz wrote:

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On Sun, 7 Oct 2018, Segher Boessenkool wrote:

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On Sun, Oct 07, 2018 at 11:18:06AM +0200, Borislav Petkov wrote:

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Now, Richard suggested doing something like:

 1) inline asm ("...")

What would the semantics of this be?

The size of the inline asm wouldn't be counted towards the inliner size 
limits (or be counted as "1").

That sounds like a good option.

Yes, I also like it for simplicity.  It also avoids the requirement
of translating the number (in bytes?) given by the user to
"number of GIMPLE instructions" as needed by the inliner.

This patch implements this, for C only so far.  And the syntax is
"asm inline", which is more in line with other syntax.

How does this look?

Cool, thanks for implementing this!

In the kernel we'd likely wrap this in some "asm_inline()" type of construct to be
compatible with older toolchains and other compilers.

Thanks,

	Ingo