On Wed, 11 Nov 2015, Jiong Wang wrote: > As discussed at https://gcc.gnu.org/bugzilla/show_bug.cgi?id=68234, this > patch haven't touch the existed code logic in vrp_visit_phi_node, it > only entends SCEV check to those VR_VARYING loop PHI node. > > Previously, we only do this check if the PHI node is with valid range > info but later dropped either side to infinite. The miss of those PHI > node with initial estimiation of VR_VARYING caused the missing of some > further optimization opportunity, for example the testcase included in > this patch, with improved range info, we can efficient turn the signed > divide into right shift. > > This patch pass x86-64 and AArch64 boostrap, no regression on both. > Meanwhile a simple benchmaring shows there are quite a few new VR_RANGE > found after this patch during gcc bootstrapping. There is no performance > regression on spec2006 int on aarch64. > > During gcc bootstrapping, on x86-64 there are 4828 new VR_VARYING -> VR_RANGE > found by vrp1, and 5008 new by vrp2. > > While on AArch64 there are 44756 new by vrp1, and 6047 new by vrp2. > > OK for trunk?
Ok. Thanks, Richard. > 2015-11-11 Richard Biener <rgue...@gcc.gnu.org> > Jiong Wang <jiong.w...@arm.com> > gcc/ > PR tree-optimization/68234 > * tree-vrp.c (vrp_visit_phi_node): Extend SCEV check to those loop PHI > node which estimiated to be VR_VARYING initially. > > gcc/testsuite/ > * gcc.dg/tree-ssa/pr68234.c: New testcase.
