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From:   David Laight <David.Laight@ACULAB.COM>
To:     'Segher Boessenkool' <segher@kernel.crashing.org>,
        Linus Torvalds <torvalds@linux-foundation.org>
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Subject: RE: [PATCH v5] x86: use builtins to read eflags
Thread-Topic: [PATCH v5] x86: use builtins to read eflags
Thread-Index: AQHYOxW8eN2QBTsI8UeuD4rBr3nbhqzFuaDg
Date:   Fri, 18 Mar 2022 22:36:48 +0000
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From: Segher Boessenkool
> Sent: 18 March 2022 22:09
...
> It generally is a very good idea to
> have a redzone though, without it you pay much more than necessary for
> frame setup and teardown in leaf functions (similar to some of what the
> misnamed "shrink-wrapping" optimisation does, but the two are mostly
> independent, the benefits add up).

Are there really leaf functions that need to spill data to stack
where the cost of setting up a stack frame is significant?

I'd have thought that was relatively rare.

	David

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