[PATCH][X86] __builtin_ctz/clz sometimed defined for zero input

[Sean Silva]

On Mon, Oct 27, 2014 at 6:16 PM, Robinson, Paul <
Paul_Robinson at playstation.sony.com> wrote:

>  I don't know about Mac, but on my Ubuntu, Intrin.h shows up in the
> expected place:
>
>
>
> ~/projects/upstream/writeable/obj$ find . -name Intrin.h
>
> ./Debug+Asserts/lib/clang/3.6.0/include/Intrin.h
>
> ./Debug+Asserts/lib/clang/3.5.0/include/Intrin.h
>
> ./Debug+Asserts/lib/clang/3.4/include/Intrin.h
>
> ./Debug+Asserts/lib/clang/3.5/include/Intrin.h
>

I presume that isn't where existing software for those platforms looks for
them.

-- Sean Silva


>
>
> *From:* Chandler Carruth [mailto:chandlerc at google.com]
> *Sent:* Monday, October 27, 2014 5:17 PM
> *To:* Robinson, Paul
> *Cc:* Sean Silva; cfe-commits at cs.uiuc.edu
> *Subject:* Re: [PATCH][X86] __builtin_ctz/clz sometimed defined for zero
> input
>
>
>
>
>
> On Mon, Oct 27, 2014 at 5:02 PM, Robinson, Paul <
> Paul_Robinson at playstation.sony.com> wrote:
>
> That makes lzcntintrin.h completely pointless.  They'd just be alternate
> names for the functions in Intrin.h.
>
>
> If those names need to be supported for compatibility and portability then
> it still seems to have a point.
>
>
>
> Note that Intrin.h doesn't exist on Linux or Mac.
>
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