Richard, I implemented this by passing callback function in_region which returns true if block belongs to region. I am testing it now
I attach modified patch for your quick review. Thanks. 2016-10-11 13:33 GMT+03:00 Richard Biener <richard.guent...@gmail.com>: > On Mon, Oct 10, 2016 at 4:17 PM, Yuri Rumyantsev <ysrum...@gmail.com> wrote: >> Richard, >> >> If "fake" exit or entry block is created in dominance how we can >> determine what is its the only predecessor or successor without using >> a notion of loop? > > The caller passes in an entry and exit edge instead of a block or loop. > > Richard. > >> 2016-10-10 15:00 GMT+03:00 Richard Biener <richard.guent...@gmail.com>: >>> On Mon, Oct 10, 2016 at 1:42 PM, Yuri Rumyantsev <ysrum...@gmail.com> wrote: >>>> Thanks Richard for your comments. >>>> I'd like to answer on your last comment regarding use split_edge() >>>> instead of creating fake post-header. I started with this splitting >>>> but it requires to fix-up closed ssa form by creating additional phi >>>> nodes, so I decided to use only cfg change without updating ssa form. >>>> Other changes look reasonable and will fix them. >>> >>> Ah. In this case can you investigate what it takes to make the entry/exit >>> edges rather than BBs? That is, introduce those "fakes" only internally >>> in dominance.c? >>> >>>> 2016-10-10 12:52 GMT+03:00 Richard Biener <richard.guent...@gmail.com>: >>>>> On Wed, Oct 5, 2016 at 3:22 PM, Yuri Rumyantsev <ysrum...@gmail.com> >>>>> wrote: >>>>>> Hi All, >>>>>> >>>>>> Here is implementation of Richard proposal: >>>>>> >>>>>> < For general infrastructure it would be nice to expose a >>>>>> (post-)dominator >>>>>> < compute for MESE (post-dominators) / SEME (dominators) regions. I >>>>>> believe >>>>>> < what makes if-conversion expensive is the post-dom compute which >>>>>> happens >>>>>> < for each loop for the whole function. It shouldn't be very difficult >>>>>> < to write this, >>>>>> < sharing as much as possible code with the current DOM code might need >>>>>> < quite some refactoring though. >>>>>> >>>>>> I implemented this proposal by adding calculation of dominance info >>>>>> for SESE regions and incorporate this change to if conversion pass. >>>>>> SESE region is built by adding loop pre-header and possibly fake >>>>>> post-header blocks to loop body. Fake post-header is deleted after >>>>>> predication completion. >>>>>> >>>>>> Bootstrapping and regression testing did not show any new failures. >>>>>> >>>>>> Is it OK for trunk? >>>>> >>>>> It's mostly reasonable but I have a few comments. First, re-using >>>>> bb->dom[] for the dominator info is somewhat fragile but indeed >>>>> a requirement to make the patch reasonably small. Please, >>>>> in calculate_dominance_info_for_region, make sure that >>>>> !dom_info_available_p (dir). >>>>> >>>>> You pass loop * everywhere but require ->aux to be set up as >>>>> an array of BBs forming the region with special BBs at array ends. >>>>> >>>>> Please instead pass in a vec<basic_block> which avoids using ->aux >>>>> and also allows other non-loop-based SESE regions to be used >>>>> (I couldn't spot anything that relies on this being a loop). >>>>> >>>>> Adding a convenience wrapper for loop * would be of course nice, >>>>> to cover the special pre/post-header code in tree-if-conv.c. >>>>> >>>>> In theory a SESE region is fully specified by its entry end exit _edge_, >>>>> so you might want to see if it's possible to use such a pair of edges >>>>> to guard the dfs/idom walks to avoid the need to create fake blocks. >>>>> >>>>> Btw, instead of using create_empty_bb, unchecked_make_edge, etc. >>>>> please use split_edge() of the entry/exit edges. >>>>> >>>>> Richard. >>>>> >>>>>> ChangeLog: >>>>>> 2016-10-05 Yuri Rumyantsev <ysrum...@gmail.com> >>>>>> >>>>>> * dominance.c : Include cfgloop.h for loop recognition. >>>>>> (dom_info): Add new functions and add boolean argument to recognize >>>>>> computation for loop region. >>>>>> (dom_info::dom_info): New function. >>>>>> (dom_info::calc_dfs_tree): Add boolean argument IN_REGION to not >>>>>> handle unvisited blocks. >>>>>> (dom_info::calc_idoms): Likewise. >>>>>> (compute_dom_fast_query_in_region): New function. >>>>>> (calculate_dominance_info): Invoke calc_dfs_tree and calc_idoms with >>>>>> false argument. >>>>>> (calculate_dominance_info_for_region): New function. >>>>>> (free_dominance_info_for_region): Likewise. >>>>>> (verify_dominators): Invoke calc_dfs_tree and calc_idoms with false >>>>>> argument. >>>>>> * dominance.h: Add prototype for introduced functions >>>>>> calculate_dominance_info_for_region and >>>>>> free_dominance_info_for_region. >>>>>> tree-if-conv.c: Add to local variables ifc_sese_bbs & fake_postheader. >>>>>> (build_sese_region): New function. >>>>>> (if_convertible_loop_p_1): Invoke local version of post-dominators >>>>>> calculation, free it after basic block predication and delete created >>>>>> fake post-header block if any. >>>>>> (tree_if_conversion): Delete call of free_dominance_info for >>>>>> post-dominators, free ifc_sese_bbs which represents SESE region. >>>>>> (pass_if_conversion::execute): Delete detection of infinite loops >>>>>> and fake edges to exit block since post-dominator calculation is >>>>>> performed per if-converted loop only.
patch.2
Description: Binary data
