Hi, On Tue, 1 Mar 2016, Richard Biener wrote:
> > What about the example I gave above? Is it unrealistic for compilers > > do ever do something like this, or is it just unlikely to gain much > > performance, or is it just that GCC does not do this today? > > GCC does not do this today with the exception of value-profiling. GCC > in other cases does not establish equivalences but only relations (a < > b, etc.) that are not a problem as far as I can see because those do not > allow to change expressions using a to use b. Made up example using relations: int32 a, b; a = (b >> 31) & 1; --> if (b < 0) a = 1; else a = 0; data-dep to control-dep and only relations :) (I think this is taken care of by Pauls wording, ignoring the fact that these aren't pointers anyway and hence don't carry a dependency through them, only onto them at max) Ciao, Michael.
