Messages in this thread | | | From | Linus Torvalds <> | Date | Mon, 12 Mar 2018 16:57:59 -0700 | Subject | Re: [PATCH v3] kernel.h: Skip single-eval logic on literals in min()/max() |
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On Mon, Mar 12, 2018 at 3:55 PM, Andrew Morton <akpm@linux-foundation.org> wrote: > > Replacing the __builtin_choose_expr() with ?: works of course.
Hmm. That sounds like the right thing to do. We were so myopically staring at the __builtin_choose_expr() problem that we overlooked the obvious solution.
Using __builtin_constant_p() together with a ?: is in fact our common pattern, so that should be fine. The only real reason to use __builtin_choose_expr() is if you want to get the *type* to vary depending on which side you choose, but that's not an issue for min/max.
> What will be the runtime effects?
There should be none. Gcc will turn the conditional for the ?: into a constant, and DTRT.
Linus
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