On 2016.08.03 at 15:47 +0200, Richard Biener wrote: > On Wed, Aug 3, 2016 at 6:00 AM, Patrick Palka <patr...@parcs.ath.cx> wrote: > > VRP currently has functionality to eliminate case labels that lie > > completely outside of the switch operand's value range. This patch > > complements this functionality by teaching VRP to also truncate the case > > label ranges that partially overlap with the operand's value range. > > > > Bootstrapped and regtested on x86_64-pc-linux-gnu. Does this look like > > a reasonable optimization? Admittedly, its effect will almost always be > > negligible except in cases where a case label range spans a large number > > of values which is a pretty rare thing. The optimization triggered > > about 250 times during bootstrap. > > I think it's most useful when the range collapses to a single value. > > Ok.
Apparently typedefs aren't handled correctly, see: https://gcc.gnu.org/bugzilla/show_bug.cgi?id=72810 -- Markus
