Re: "eliminate warn_on_slowpath()" change causes many gcc-3.2.3 warnings

From: H. Peter Anvin
Date: Sat Jan 17 2009 - 18:43:49 EST

Linus Torvalds wrote:
> Don't do this. That just forces a load off a complex pointer instead, with
> no upsides. At least if it was
> extern const char warn_slowpath_nofmt[];
> it would only load the pointer itself, which is still a fairly expensive
> op, but at least doesn't require the extra memory load.
> But you'd be better off jusst making it something like
> #define NO_FMT ((const char *)(-1))
> instead, which is really much more obvious, and doesn't need any of that
> "get a pointer" overhead.

At least on x86, the two ops should be the same cost?


H. Peter Anvin, Intel Open Source Technology Center
I work for Intel. I don't speak on their behalf.

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