Re: x86: A fast way to check capabilities of the current cpu

[Miles Bader]

Miguel Ojeda <miguel.ojeda.sandonis@xxxxxxxxx> writes:
>>> If they aren't, and are stored in a variable for whatever reason, then
>>> the || form will generate additional instructions to booleanize the
>>> value for no good reason.
>
> I think hpa was talking about some code where gcc can not optimize out
> the assignment (e.g. volatile, complex code, using the int outside
> conditional expressions, etc.).

Sure, but that seems to assume that the alternatives are otherwise
equivalent in the common case, when used in a boolean context.

If that's not true then one risks pessimizing the common case to make an
uncommon case more efficient.

-Miles

-- 
Suburbia: where they tear out the trees and then name streets after them.
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