On Thu, Jun 25, 2020 at 1:07 PM Eric Botcazou <botca...@adacore.com> wrote: > > Hi, > > ...into bit tests, as done by optimize_range_tests_to_bit_test of the reassoc > pass. The patch is aimed at addressing the following two issues: > > 1. In order to protect the shift operation from undefinedness, the new bit > test is guarded with a new test, but this new test uses the range of the bit > test values, not that of the shift operation so, if the input is in the range > of the shift operation but not of the bit test values, then the subsequent VRP > pass cannot eliminate the new test. Moreover changing the new test to use the > range of the shift operation, instead of that of the bit test values, in the > general case would pessimize the cases which are in between. > > 2. If the new test can be eliminated, then it becomes profitable to do the > optimization into a bit test for one fewer comparison in the source code. > > Therefore the patch changes optimize_range_tests_to_bit_test to use the range > info of the input in order to eliminate the new test if possible. > > Tested on x86-64/Linux, OK for the mainline?
OK. Thanks, Richard. > > 2020-06-25 Eric Botcazou <ebotca...@adacore.com> > > * tree-ssa-reassoc.c (dump_range_entry): New function. > (debug_range_entry): New debug function. > (update_range_test): Invoke dump_range_entry for dumping. > (optimize_range_tests_to_bit_test): Merge the entry test in the bit > test when possible and lower the profitability threshold in this case. > > > 2020-06-25 Eric Botcazou <ebotca...@adacore.com> > > * exp_ch4.adb (Expand_Set_Membership): Expand the membership test > using left associativity instead of right associativity. > > > 2020-06-25 Eric Botcazou <ebotca...@adacore.com> > > * gnat.dg/opt86_pkg.ads: New helper. > * gnat.dg/opt86a.adb: New test. > * gnat.dg/opt86b.adb: Likewise. > * gnat.dg/opt86c.adb: Likewise. > > -- > Eric Botcazou
