On Tue, Jul 10, 2012 at 8:56 AM, Uros Bizjak <ubiz...@gmail.com> wrote: > Hello! > >> TARGET_BRANCH_PREDICTION_HINTS isn't used at all. This patch removes it. >> Bootstrapped&tested (incl. -m32) on x86_64-unknown-linux-gnu. OK for trunk? > > This infrastructure can be used for future targets, so let's leave it as is.
Hi Uros, Yes, I suppose that's theoretically possible. However, I don't think this is very likely to happen. The branch hints only ever were supported for P4, but even Intel's own ICC never emits them (http://sources.redhat.com/ml/binutils/2004-07/msg00322.html). In fact, the whole Netburst microachitecture appears to have been abandoned (in favor of the ppro microachitecture). For EM64T another form of branch hints was introduced (which GCC doesn't support and ICC doesn't emit). So any future target that would need this, would have to be a 32-bits, deep-pipeline microarchitecture. I personally don't believe that such an architecture will emerge, given the history of failure of this concept. Are these arguments reason enough for you to reconsider? :-) Ciao! Steven
