Displaying 2 results from an estimated 2 matches for "unpredictabi".
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unpredictabie
2015 Jun 26
2
[LLVMdev] [cfe-dev] bitwise ops on booleans
On Fri, Jun 26, 2015 at 2:17 PM, Joerg Sonnenberger <joerg at britannica.bec.de
> wrote:
> On Fri, Jun 26, 2015 at 12:51:38PM -0600, Sanjay Patel wrote:
> > Assuming the transform is correct, what is the recommended way to write
> > this in C/C++ to achieve the desired effect: we want both comparisons to
> be
> > evaluated (do *not* want short-circuiting)?
>
>
2015 Jun 27
2
[LLVMdev] [cfe-dev] bitwise ops on booleans
...anch prediction!) but it should be a detailed
> arch decision of how to lower this kind of code.
>
>
> The programmer may have more knowledge about the predictability of a
> specific branch and would like a way to specify that to the
> compiler.
>
> We could introduce an *unpredictabie* annotation to LLVM if there is
> sufficient demand for this. Specifically, this is different from a
> 50/50 probability, as it implies a lack of pattern which the
> processor can exploit to predict the behavior. This doesn't seem
> like a bad construct for LLVM to have, although i...