On Mon, Sep 9, 2013 at 10:01 AM, Bin.Cheng <amker.ch...@gmail.com> wrote: > On Wed, Sep 4, 2013 at 5:20 PM, Richard Biener <rguent...@suse.de> wrote: >> >> The patch below moves IVOPTs out of the GIMPLE loop pipeline more >> closer to RTL expansion. That's done for multiple reasons. >> >> First, the loop passes that at the moment preceede IVOPTs leave >> around IL that is in desparate need of basic re-optimization >> like CSE, constant propagation and DCE. That puts extra load >> on IVOPTs and its cost model, increasing compile-time and >> possibly confusing it. >> >> Second, IVOPTs introduces lowered memory accesses that it >> expects to stay as is, likewise it produces auto-inc/dec >> sequences that it expects to stay as is until RTL expansion. >> Passes such as DOM can break this expectation and make the >> work done by IVOPTs a waste. >> >> I remember doing this excercise in the GCC 4.3 timeframe where >> benchmarking on x86_64 showed no gains or losses (but x86_64 >> isn't very sensitive to IV choices). >> >> Any help with benchmarking this on targets other than x86_64 >> is appreciated (I'll re-do x86_64).
I will bootstrap and make check on arm a15. -- Best Regards.
