From: Richard Biener Date: Thu, 11 May 2017 09:16:00 +0000 (+0000) Subject: tree-ssa-pre.c (eliminate_dom_walker::before_dom_children): Skip unreachable blocks... X-Git-Tag: upstream/12.2.0~39607 X-Git-Url: http://review.tizen.org/git/?a=commitdiff_plain;h=7581ce9a1ad6df9c8998a3c74256837a1ff6f7cc;p=platform%2Fupstream%2Fgcc.git tree-ssa-pre.c (eliminate_dom_walker::before_dom_children): Skip unreachable blocks and destinations. 2017-05-11 Richard Biener * tree-ssa-pre.c (eliminate_dom_walker::before_dom_children): Skip unreachable blocks and destinations. (eliminate): Move stmt removal and fixup ... (fini_eliminate): ... here. Skip inserted exprs. (pass_pre::execute): Move fini_pre after fini_eliminate. * tree-ssa-tailmerge.c: Include tree-cfgcleanup.h. (tail_merge_optimize): Run cleanup_tree_cfg if requested by PRE to get rid of dead code that has invalid SSA form and split critical edges again. From-SVN: r247882 --- diff --git a/gcc/ChangeLog b/gcc/ChangeLog index 9fe29bd..be20be0 100644 --- a/gcc/ChangeLog +++ b/gcc/ChangeLog @@ -1,3 +1,15 @@ +2017-05-11 Richard Biener + + * tree-ssa-pre.c (eliminate_dom_walker::before_dom_children): + Skip unreachable blocks and destinations. + (eliminate): Move stmt removal and fixup ... + (fini_eliminate): ... here. Skip inserted exprs. + (pass_pre::execute): Move fini_pre after fini_eliminate. + * tree-ssa-tailmerge.c: Include tree-cfgcleanup.h. + (tail_merge_optimize): Run cleanup_tree_cfg if requested by + PRE to get rid of dead code that has invalid SSA form and + split critical edges again. + 2017-05-11 Bin Cheng * rtlanal.c (rtx_cost): Handle TRUNCATE between tieable modes. diff --git a/gcc/tree-ssa-pre.c b/gcc/tree-ssa-pre.c index 65cf523..38723df 100644 --- a/gcc/tree-ssa-pre.c +++ b/gcc/tree-ssa-pre.c @@ -4196,9 +4196,14 @@ eliminate_dom_walker::before_dom_children (basic_block b) /* Mark new bb. */ el_avail_stack.safe_push (NULL_TREE); - /* ??? If we do nothing for unreachable blocks then this will confuse - tailmerging. Eventually we can reduce its reliance on SCCVN now - that we fully copy/constant-propagate (most) things. */ + /* Skip unreachable blocks marked unreachable during the SCCVN domwalk. */ + edge_iterator ei; + edge e; + FOR_EACH_EDGE (e, ei, b->preds) + if (e->flags & EDGE_EXECUTABLE) + break; + if (! e) + return NULL; for (gphi_iterator gsi = gsi_start_phis (b); !gsi_end_p (gsi);) { @@ -4695,10 +4700,8 @@ eliminate_dom_walker::before_dom_children (basic_block b) } /* Replace destination PHI arguments. */ - edge_iterator ei; - edge e; FOR_EACH_EDGE (e, ei, b->succs) - { + if (e->flags & EDGE_EXECUTABLE) for (gphi_iterator gsi = gsi_start_phis (e->dest); !gsi_end_p (gsi); gsi_next (&gsi)) @@ -4717,7 +4720,6 @@ eliminate_dom_walker::before_dom_children (basic_block b) gimple_set_plf (SSA_NAME_DEF_STMT (sprime), NECESSARY, true); } } - } return NULL; } @@ -4743,9 +4745,6 @@ eliminate_dom_walker::after_dom_children (basic_block) static unsigned int eliminate (bool do_pre) { - gimple_stmt_iterator gsi; - gimple *stmt; - need_eh_cleanup = BITMAP_ALLOC (NULL); need_ab_cleanup = BITMAP_ALLOC (NULL); @@ -4761,6 +4760,18 @@ eliminate (bool do_pre) el_avail.release (); el_avail_stack.release (); + return el_todo; +} + +/* Perform CFG cleanups made necessary by elimination. */ + +static unsigned +fini_eliminate (void) +{ + gimple_stmt_iterator gsi; + gimple *stmt; + unsigned todo = 0; + /* We cannot remove stmts during BB walk, especially not release SSA names there as this confuses the VN machinery. The stmts ending up in el_to_remove are either stores or simple copies. @@ -4769,12 +4780,6 @@ eliminate (bool do_pre) { stmt = el_to_remove.pop (); - if (dump_file && (dump_flags & TDF_DETAILS)) - { - fprintf (dump_file, "Removing dead stmt "); - print_gimple_stmt (dump_file, stmt, 0, 0); - } - tree lhs; if (gimple_code (stmt) == GIMPLE_PHI) lhs = gimple_phi_result (stmt); @@ -4782,8 +4787,15 @@ eliminate (bool do_pre) lhs = gimple_get_lhs (stmt); if (inserted_exprs - && TREE_CODE (lhs) == SSA_NAME) - bitmap_clear_bit (inserted_exprs, SSA_NAME_VERSION (lhs)); + && TREE_CODE (lhs) == SSA_NAME + && bitmap_bit_p (inserted_exprs, SSA_NAME_VERSION (lhs))) + continue; + + if (dump_file && (dump_flags & TDF_DETAILS)) + { + fprintf (dump_file, "Removing dead stmt "); + print_gimple_stmt (dump_file, stmt, 0, 0); + } gsi = gsi_for_stmt (stmt); if (gimple_code (stmt) == GIMPLE_PHI) @@ -4800,7 +4812,7 @@ eliminate (bool do_pre) } /* Removing a stmt may expose a forwarder block. */ - el_todo |= TODO_cleanup_cfg; + todo |= TODO_cleanup_cfg; } el_to_remove.release (); @@ -4819,18 +4831,10 @@ eliminate (bool do_pre) } if (fixup_noreturn_call (stmt)) - el_todo |= TODO_cleanup_cfg; + todo |= TODO_cleanup_cfg; } el_to_fixup.release (); - return el_todo; -} - -/* Perform CFG cleanups made necessary by elimination. */ - -static unsigned -fini_eliminate (void) -{ bool do_eh_cleanup = !bitmap_empty_p (need_eh_cleanup); bool do_ab_cleanup = !bitmap_empty_p (need_ab_cleanup); @@ -4844,8 +4848,8 @@ fini_eliminate (void) BITMAP_FREE (need_ab_cleanup); if (do_eh_cleanup || do_ab_cleanup) - return TODO_cleanup_cfg; - return 0; + todo |= TODO_cleanup_cfg; + return todo; } /* Borrow a bit of tree-ssa-dce.c for the moment. @@ -5110,8 +5114,8 @@ pass_pre::execute (function *fun) remove_dead_inserted_code (); scev_finalize (); - fini_pre (); todo |= fini_eliminate (); + fini_pre (); loop_optimizer_finalize (); /* Restore SSA info before tail-merging as that resets it as well. */ diff --git a/gcc/tree-ssa-tail-merge.c b/gcc/tree-ssa-tail-merge.c index 71f874d..8765fdd 100644 --- a/gcc/tree-ssa-tail-merge.c +++ b/gcc/tree-ssa-tail-merge.c @@ -205,6 +205,7 @@ along with GCC; see the file COPYING3. If not see #include "tree-ssa-sccvn.h" #include "cfgloop.h" #include "tree-eh.h" +#include "tree-cfgcleanup.h" /* Describes a group of bbs with the same successors. The successor bbs are cached in succs, and the successor edge flags are cached in succ_flags. @@ -1717,6 +1718,16 @@ tail_merge_optimize (unsigned int todo) timevar_push (TV_TREE_TAIL_MERGE); + /* We enter from PRE which has critical edges split. Elimination + does not process trivially dead code so cleanup the CFG if we + are told so. And re-split critical edges then. */ + if (todo & TODO_cleanup_cfg) + { + cleanup_tree_cfg (); + todo &= ~TODO_cleanup_cfg; + split_critical_edges (); + } + if (!dom_info_available_p (CDI_DOMINATORS)) { /* PRE can leave us with unreachable blocks, remove them now. */