From 24c40f9a2cc832de74cb55f6ec1dfb45b7161379 Mon Sep 17 00:00:00 2001 From: Richard Biener Date: Mon, 24 Apr 2017 11:27:44 +0000 Subject: [PATCH] tree-ssa-sccvn.h (run_scc_vn): Adjust prototype. 2017-04-24 Richard Biener * tree-ssa-sccvn.h (run_scc_vn): Adjust prototype. * tree-ssa-sccvn.c (print_scc): Print SCC size. (extract_and_process_scc_for_name): Never fail but drop SCC to varying. (DFS): Adjust and never fail. (sccvn_dom_walker::fail): Remove. (sccvn_dom_walker::before_dom_children): Adjust. (run_scc_vn): Likewise and never fail. * tree-ssa-pre.c (pass_pre::execute): Adjust. (pass_fre::execute): Likewise. From-SVN: r247092 --- gcc/ChangeLog | 12 +++++++ gcc/tree-ssa-pre.c | 9 ++---- gcc/tree-ssa-sccvn.c | 76 ++++++++++++++++++++------------------------ gcc/tree-ssa-sccvn.h | 2 +- 4 files changed, 49 insertions(+), 50 deletions(-) diff --git a/gcc/ChangeLog b/gcc/ChangeLog index 1facf361a77..86ec5c1a3f4 100644 --- a/gcc/ChangeLog +++ b/gcc/ChangeLog @@ -1,3 +1,15 @@ +2017-04-24 Richard Biener + + * tree-ssa-sccvn.h (run_scc_vn): Adjust prototype. + * tree-ssa-sccvn.c (print_scc): Print SCC size. + (extract_and_process_scc_for_name): Never fail but drop SCC to varying. + (DFS): Adjust and never fail. + (sccvn_dom_walker::fail): Remove. + (sccvn_dom_walker::before_dom_children): Adjust. + (run_scc_vn): Likewise and never fail. + * tree-ssa-pre.c (pass_pre::execute): Adjust. + (pass_fre::execute): Likewise. + 2017-04-24 Richard Biener PR tree-optimization/79725 diff --git a/gcc/tree-ssa-pre.c b/gcc/tree-ssa-pre.c index 2c6405aa7a8..b4095bfdeed 100644 --- a/gcc/tree-ssa-pre.c +++ b/gcc/tree-ssa-pre.c @@ -5086,11 +5086,7 @@ pass_pre::execute (function *fun) loop_optimizer_init may create new phis, etc. */ loop_optimizer_init (LOOPS_NORMAL); - if (!run_scc_vn (VN_WALK)) - { - loop_optimizer_finalize (); - return 0; - } + run_scc_vn (VN_WALK); init_pre (); scev_initialize (); @@ -5202,8 +5198,7 @@ pass_fre::execute (function *fun) { unsigned int todo = 0; - if (!run_scc_vn (VN_WALKREWRITE)) - return 0; + run_scc_vn (VN_WALKREWRITE); memset (&pre_stats, 0, sizeof (pre_stats)); diff --git a/gcc/tree-ssa-sccvn.c b/gcc/tree-ssa-sccvn.c index 36386cf3e60..f307e2e8fe0 100644 --- a/gcc/tree-ssa-sccvn.c +++ b/gcc/tree-ssa-sccvn.c @@ -3153,7 +3153,7 @@ print_scc (FILE *out, vec scc) tree var; unsigned int i; - fprintf (out, "SCC consists of:"); + fprintf (out, "SCC consists of %u:", scc.length ()); FOR_EACH_VEC_ELT (scc, i, var) { fprintf (out, " "); @@ -4316,7 +4316,7 @@ process_scc (vec scc) and process them. Returns true if all went well, false if we run into resource limits. */ -static bool +static void extract_and_process_scc_for_name (tree name) { auto_vec scc; @@ -4332,24 +4332,37 @@ extract_and_process_scc_for_name (tree name) scc.safe_push (x); } while (x != name); - /* Bail out of SCCVN in case a SCC turns out to be incredibly large. */ - if (scc.length () - > (unsigned)PARAM_VALUE (PARAM_SCCVN_MAX_SCC_SIZE)) + /* Drop all defs in the SCC to varying in case a SCC turns out to be + incredibly large. + ??? Just switch to a non-optimistic mode that avoids any iteration. */ + if (scc.length () > (unsigned)PARAM_VALUE (PARAM_SCCVN_MAX_SCC_SIZE)) { if (dump_file) - fprintf (dump_file, "WARNING: Giving up with SCCVN due to " - "SCC size %u exceeding %u\n", scc.length (), - (unsigned)PARAM_VALUE (PARAM_SCCVN_MAX_SCC_SIZE)); - - return false; + { + print_scc (dump_file, scc); + fprintf (dump_file, "WARNING: Giving up value-numbering SCC due to " + "size %u exceeding %u\n", scc.length (), + (unsigned)PARAM_VALUE (PARAM_SCCVN_MAX_SCC_SIZE)); + } + tree var; + unsigned i; + FOR_EACH_VEC_ELT (scc, i, var) + { + gimple *def = SSA_NAME_DEF_STMT (var); + mark_use_processed (var); + if (SSA_NAME_IS_DEFAULT_DEF (var) + || gimple_code (def) == GIMPLE_PHI) + set_ssa_val_to (var, var); + else + defs_to_varying (def); + } + return; } if (scc.length () > 1) sort_scc (scc); process_scc (scc); - - return true; } /* Depth first search on NAME to discover and process SCC's in the SSA @@ -4359,7 +4372,7 @@ extract_and_process_scc_for_name (tree name) Returns true if successful, false if we stopped processing SCC's due to resource constraints. */ -static bool +static void DFS (tree name) { auto_vec itervec; @@ -4399,12 +4412,11 @@ start_over: { /* See if we found an SCC. */ if (VN_INFO (name)->low == VN_INFO (name)->dfsnum) - if (!extract_and_process_scc_for_name (name)) - return false; + extract_and_process_scc_for_name (name); /* Check if we are done. */ if (namevec.is_empty ()) - return true; + return; /* Restore the last use walker and continue walking there. */ use = name; @@ -4687,7 +4699,7 @@ class sccvn_dom_walker : public dom_walker { public: sccvn_dom_walker () - : dom_walker (CDI_DOMINATORS, true), fail (false), cond_stack (0) {} + : dom_walker (CDI_DOMINATORS, true), cond_stack (0) {} virtual edge before_dom_children (basic_block); virtual void after_dom_children (basic_block); @@ -4697,7 +4709,6 @@ public: void record_conds (basic_block, enum tree_code code, tree lhs, tree rhs, bool value); - bool fail; auto_vec > > cond_stack; }; @@ -4793,9 +4804,6 @@ sccvn_dom_walker::before_dom_children (basic_block bb) edge e; edge_iterator ei; - if (fail) - return NULL; - if (dump_file && (dump_flags & TDF_DETAILS)) fprintf (dump_file, "Visiting BB %d\n", bb->index); @@ -4851,12 +4859,8 @@ sccvn_dom_walker::before_dom_children (basic_block bb) { gphi *phi = gsi.phi (); tree res = PHI_RESULT (phi); - if (!VN_INFO (res)->visited - && !DFS (res)) - { - fail = true; - return NULL; - } + if (!VN_INFO (res)->visited) + DFS (res); } for (gimple_stmt_iterator gsi = gsi_start_bb (bb); !gsi_end_p (gsi); gsi_next (&gsi)) @@ -4864,12 +4868,8 @@ sccvn_dom_walker::before_dom_children (basic_block bb) ssa_op_iter i; tree op; FOR_EACH_SSA_TREE_OPERAND (op, gsi_stmt (gsi), i, SSA_OP_ALL_DEFS) - if (!VN_INFO (op)->visited - && !DFS (op)) - { - fail = true; - return NULL; - } + if (!VN_INFO (op)->visited) + DFS (op); } /* Finally look at the last stmt. */ @@ -4941,7 +4941,7 @@ sccvn_dom_walker::before_dom_children (basic_block bb) due to resource constraints. DEFAULT_VN_WALK_KIND_ specifies how we use the alias oracle walking during the VN process. */ -bool +void run_scc_vn (vn_lookup_kind default_vn_walk_kind_) { size_t i; @@ -4977,12 +4977,6 @@ run_scc_vn (vn_lookup_kind default_vn_walk_kind_) SSA defs and decide whether outgoing edges are not executable. */ sccvn_dom_walker walker; walker.walk (ENTRY_BLOCK_PTR_FOR_FN (cfun)); - if (walker.fail) - { - scc_vn_restore_ssa_info (); - free_scc_vn (); - return false; - } /* Initialize the value ids and prune out remaining VN_TOPs from dead code. */ @@ -5027,8 +5021,6 @@ run_scc_vn (vn_lookup_kind default_vn_walk_kind_) } } } - - return true; } /* Return the maximum value id we have ever seen. */ diff --git a/gcc/tree-ssa-sccvn.h b/gcc/tree-ssa-sccvn.h index ec00c37cca2..53a21afb300 100644 --- a/gcc/tree-ssa-sccvn.h +++ b/gcc/tree-ssa-sccvn.h @@ -212,7 +212,7 @@ enum vn_lookup_kind { VN_NOWALK, VN_WALK, VN_WALKREWRITE }; extern vn_ssa_aux_t VN_INFO (tree); extern vn_ssa_aux_t VN_INFO_GET (tree); tree vn_get_expr_for (tree); -bool run_scc_vn (vn_lookup_kind); +void run_scc_vn (vn_lookup_kind); void free_scc_vn (void); void scc_vn_restore_ssa_info (void); tree vn_nary_op_lookup (tree, vn_nary_op_t *); -- 2.30.2