On 7/1/19 4:24 AM, Aldy Hernandez wrote: > This is completely unrelated to range-ops itself, but may yield better > results in value_range intersections. It's just something I found while > working on VRP, and have been dragging around on our branch. > > If we know the intersection of two ranges is the empty set, there is no > need to conservatively add anything to the result. > > Tested on x86-64 Linux with --enable-languages=all. > > Aldy > > range-ops-intersect-undefined.patch > > commit 4f9aa7bd1066267eee92f622ff29d78534158e20 > Author: Aldy Hernandez <al...@redhat.com> > Date: Fri Jun 28 11:34:19 2019 +0200 > > Do not try to further refine a VR_UNDEFINED result when intersecting > value_ranges. > > diff --git a/gcc/ChangeLog b/gcc/ChangeLog > index 01fb97cedb2..b0d78ee6871 100644 > --- a/gcc/ChangeLog > +++ b/gcc/ChangeLog > @@ -1,3 +1,9 @@ > +2019-07-01 Aldy Hernandez <al...@redhat.com> > + > + * tree-vrp.c (intersect_ranges): If we know the intersection is > + empty, there is no need to conservatively add anything else to > + the set. Do we have a test where this improves the code or at least the computed ranges?
jeff
