On Wed, Sep 12, 2018 at 2:56 PM Kyrill Tkachov <kyrylo.tkac...@foss.arm.com> wrote: > > Hi all, > > This PR is an SSA validation error where the definition ends up not > dominating a use. > This appeared after my recip_sqrt optimisation. Though the optimisation > doesn't get triggered > as there is no sqrt involved it prevents execute_cse_reciprocals_1 from > running as it's currently > an either/or situation. I think execute_cse_reciprocals_1 doesn't like it > when some divisions get > execute_cse_reciprocals_1 called on them and some don't. > > This patch changes optimize_recip_sqrt to return a boolean indicating success > and call execute_cse_reciprocals_1 > if no transform was made so that execute_cse_reciprocals_1 has a chance to > optimise it as well. > > Bootstrapped and tested on x86_64-unknown-linux-gnu. > Ok for trunk?
OK. But your analysis suggests to do it the other way around - call execute_cse_reciprocals_1 and if that leaves a division at *gsi process it with optimize_recip_sqrt? Richard. > Thanks, > Kyrill > > 2018-09-12 Kyrylo Tkachov <kyrylo.tkac...@arm.com> > > PR tree-optimization/87259 > PR lto/87283 > * tree-ssa-math-opts.c (optimize_recip_sqrt): Make function return > boolean. > (pass_cse_reciprocals::execute): Try execute_cse_reciprocals_1 if > optimize_recip_sqrt was ineffective. > > 2018-09-12 Kyrylo Tkachov <kyrylo.tkac...@arm.com> > > PR tree-optimization/87259 > * gcc.dg/pr87259.c: New test.
