Messages in this thread | | | Date | Fri, 1 Mar 2019 12:26:59 -0800 | From | Andrew Morton <> | Subject | Re: [PATCH] log2: make is_power_of_2() integer constant expression when possible |
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On Fri, 1 Mar 2019 14:52:07 +0200 Jani Nikula <jani.nikula@intel.com> wrote:
> While is_power_of_2() is an inline function and likely gets optimized > for compile time constant arguments, it still doesn't produce an integer > constant expression that could be used in, say, static data > initialization or case labels.
hm, what code wants to do these things?
> Make is_power_of_2() an integer constant expression when possible, > otherwise using the inline function to avoid multiple evaluation of the > parameter.
Spose so. But I fear that some gcc versions will get it right and others will mess it up. While this patch is under test I think it would be best to also have at least one or two callsites which actually use the compile-time evaluation feature. Possible?
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