On Mon, 20 Jul 2015, Tom de Vries wrote: > On 09/07/15 13:04, Richard Biener wrote: > > On Thu, 9 Jul 2015, Tom de Vries wrote: > > > > > On 07/07/15 17:58, Tom de Vries wrote: > > > > > If you can > > > > > handle one exit edge I also can't see the difficulty in handling > > > > > all exit edges. > > > > > > > > > > > > > Agreed, that doesn't look to complicated. I could call > > > > rewrite_virtuals_into_loop_closed_ssa for all loops in > > > > rewrite_virtuals_into_loop_closed_ssa, to get non-single_dom_exit loops > > > > exercising the code, and fix what breaks. > > > > > > Hmm, I just realised, it's more complicated than I thought. > > > > > > In loops with single_dom_exit, the exit dominates the uses outside the > > > loop, > > > so I can replace the uses of the def with the uses of the exit phi result. > > > > > > If !single_dom_exit, the exit(s) may not dominate all uses, and I need to > > > insert non-loop-exit phi nodes to deal with that. > > > > Yes. This is why I originally suggested to amend the regular > > loop-close-SSA rewriting code. > > > > This patch renames rewrite_into_loop_closed_ssa to > rewrite_into_loop_closed_ssa_1, and adds arguments: > - a loop argument, to limit the defs for which the uses are > rewritten > - a use_flags argument, to determine the type of uses rewritten: > SSA_OP_USE/SSA_OP_VIRTUAL_USES/SSA_OP_ALL_USES > > The original rewrite_into_loop_closed_ssa is reimplemented using > rewrite_into_loop_closed_ssa_1. > > And the !single_dom_exit case of rewrite_into_loop_closed_ssa is implemented > using rewrite_into_loop_closed_ssa_1. [ The patch was tested as attached, > always using rewrite_into_loop_closed_ssa_1, otherwise it would not be > triggered. ] > > Bootstrapped and reg-tested on x86_64. > > Is this sort of what you had in mind?
Yes. New functions need a comment and instead of iterating over all function BBs and checking bb->loop_father please use get_loop_body (). Of course in the final version #if 0 stuff shouldn't remain. What's the cost difference of removing the single_dom_exit special-case? Thanks, Richard. -- Richard Biener <rguent...@suse.de> SUSE LINUX GmbH, GF: Felix Imendoerffer, Jane Smithard, Dilip Upmanyu, Graham Norton, HRB 21284 (AG Nuernberg)
