tree-cfgcleanup.c File Reference

#include "config.h"
#include "system.h"
#include "coretypes.h"
#include "tm.h"
#include "tree.h"
#include "rtl.h"
#include "tm_p.h"
#include "hard-reg-set.h"
#include "basic-block.h"
#include "output.h"
#include "errors.h"
#include "flags.h"
#include "function.h"
#include "expr.h"
#include "ggc.h"
#include "langhooks.h"
#include "diagnostic.h"
#include "tree-flow.h"
#include "timevar.h"
#include "tree-dump.h"
#include "tree-pass.h"
#include "toplev.h"
#include "except.h"
#include "cfgloop.h"
#include "cfglayout.h"
#include "hashtab.h"
#include "tree-ssa-propagate.h"
#include "tree-scalar-evolution.h"

Include dependency graph for tree-cfgcleanup.c:

Go to the source code of this file.

Functions
static bool	remove_fallthru_edge (VEC(edge, gc)*ev)
static bool	cleanup_control_expr_graph ()
	VEC (tree, gc)
static bool	tree_forwarder_block_p ()
static bool	has_abnormal_incoming_edge_p ()
static bool	phi_alternatives_equal ()
static bool	remove_forwarder_block ()
static bool	cleanup_forwarder_blocks ()
static bool	cleanup_tree_cfg_1 ()
bool	cleanup_tree_cfg ()
void	cleanup_tree_cfg_loop ()
static void	remove_forwarder_block_with_phi ()
static unsigned int	merge_phi_nodes ()
static bool	gate_merge_phi ()
Variables
tree_opt_pass	pass_merge_phi

---

Function Documentation

static bool cleanup_control_expr_graph (   )  [static]

Disconnect an unreachable block in the control expression starting at block BB. Definition at line 71 of file tree-cfgcleanup.c. References bsi_stmt(), COND_EXPR_COND, find_taken_edge(), fold(), SWITCH_COND, and TREE_CODE. Referenced by VEC(). { edge taken_edge; bool retval = false; tree expr = bsi_stmt (bsi), val; if (!single_succ_p (bb)) { edge e; edge_iterator ei; switch (TREE_CODE (expr)) { case COND_EXPR: val = fold (COND_EXPR_COND (expr)); break; case SWITCH_EXPR: val = fold (SWITCH_COND (expr)); if (TREE_CODE (val) != INTEGER_CST) return false; break; default: gcc_unreachable (); } taken_edge = find_taken_edge (bb, val); if (!taken_edge) return false; /* Remove all the edges except the one that is always executed. */ for (ei = ei_start (bb->succs); (e = ei_safe_edge (ei)); ) { if (e != taken_edge) { taken_edge->probability += e->probability; taken_edge->count += e->count; remove_edge (e); retval = true; } else ei_next (&ei); } if (taken_edge->probability > REG_BR_PROB_BASE) taken_edge->probability = REG_BR_PROB_BASE; } else taken_edge = single_succ_edge (bb); bsi_remove (&bsi, true); taken_edge->flags = EDGE_FALLTHRU; /* We removed some paths from the cfg. */ free_dominance_info (CDI_DOMINATORS); return retval; }

static bool cleanup_forwarder_blocks (   )  [static]

Removes forwarder blocks. Definition at line 494 of file tree-cfgcleanup.c. References changed, remove_forwarder_block(), and tree_forwarder_block_p(). Referenced by cleanup_tree_cfg_1(). { basic_block bb; bool changed = false; basic_block *worklist = XNEWVEC (basic_block, n_basic_blocks); basic_block *current = worklist; FOR_EACH_BB (bb) { if (tree_forwarder_block_p (bb, false)) *current++ = bb; } while (current != worklist) { bb = *--current; changed |= remove_forwarder_block (bb, &current); } free (worklist); return changed; }

bool cleanup_tree_cfg (  void   )

Remove unreachable blocks and other miscellaneous clean up work. Return true if the flowgraph was modified, false otherwise. Definition at line 555 of file tree-cfgcleanup.c. References changed, and cleanup_tree_cfg_1(). Referenced by cleanup_tree_cfg_loop(), execute_cleanup_cfg_post_optimizing(), execute_cleanup_cfg_pre_ipa(), finalize_jump_threads(), fini_pre(), make_edges(), and tree_ssa_dominator_optimize(). { bool retval, changed; timevar_push (TV_TREE_CLEANUP_CFG); /* Iterate until there are no more cleanups left to do. If any iteration changed the flowgraph, set CHANGED to true. */ changed = false; do { retval = cleanup_tree_cfg_1 (); changed |= retval; } while (retval); compact_blocks (); #ifdef ENABLE_CHECKING verify_flow_info (); #endif timevar_pop (TV_TREE_CLEANUP_CFG); return changed; }

static bool cleanup_tree_cfg_1 (   )  [static]

Do one round of CFG cleanup. Definition at line 520 of file tree-cfgcleanup.c. References cleanup_forwarder_blocks(), end_recording_case_labels(), and start_recording_case_labels(). Referenced by cleanup_tree_cfg(). { bool retval; retval = cleanup_control_flow (); retval |= delete_unreachable_blocks (); /* Forwarder blocks can carry line number information which is useful when debugging, so we only clean them up when optimizing. */ if (optimize > 0) { /* cleanup_forwarder_blocks can redirect edges out of SWITCH_EXPRs, which can get expensive. So we want to enable recording of edge to CASE_LABEL_EXPR mappings around the call to cleanup_forwarder_blocks. */ start_recording_case_labels (); retval |= cleanup_forwarder_blocks (); end_recording_case_labels (); } /* Merging the blocks may create new opportunities for folding conditional branches (due to the elimination of single-valued PHI nodes). */ retval |= merge_seq_blocks (); return retval; }

void cleanup_tree_cfg_loop (  void   )

Cleanup cfg and repair loop structures. Definition at line 585 of file tree-cfgcleanup.c. References changed, cleanup_tree_cfg(), current_loops, rewrite_into_loop_closed_ssa(), scev_reset(), and TODO_update_ssa. { bool changed = cleanup_tree_cfg (); if (changed) { bitmap changed_bbs = BITMAP_ALLOC (NULL); fix_loop_structure (current_loops, changed_bbs); calculate_dominance_info (CDI_DOMINATORS); /* This usually does nothing. But sometimes parts of cfg that originally were inside a loop get out of it due to edge removal (since they become unreachable by back edges from latch). */ rewrite_into_loop_closed_ssa (changed_bbs, TODO_update_ssa); BITMAP_FREE (changed_bbs); #ifdef ENABLE_CHECKING verify_loop_structure (current_loops); #endif scev_reset (); } }

static bool gate_merge_phi (   )  [static]

Definition at line 822 of file tree-cfgcleanup.c. { return 1; }

static bool has_abnormal_incoming_edge_p (   )  [inline, static]

Return true if BB has at least one abnormal incoming edge. Definition at line 318 of file tree-cfgcleanup.c. Referenced by merge_phi_nodes(), and remove_forwarder_block(). { edge e; edge_iterator ei; FOR_EACH_EDGE (e, ei, bb->preds) if (e->flags & EDGE_ABNORMAL) return true; return false; }

static unsigned int merge_phi_nodes (   )  [static]

This pass merges PHI nodes if one feeds into another. For example, suppose we have the following: goto <bb 9> (<L9>); <L8>:; tem_17 = foo (); # tem_6 = PHI <tem_17(8), tem_23(7)>; <L9>:; # tem_3 = PHI <tem_6(9), tem_2(5)>; <L10>:; Then we merge the first PHI node into the second one like so: goto <bb 9> (<L10>); <L8>:; tem_17 = foo (); # tem_3 = PHI <tem_23(7), tem_2(5), tem_17(8)>; <L10>:; Definition at line 740 of file tree-cfgcleanup.c. References bb_for_stmt(), has_abnormal_incoming_edge_p(), has_zero_uses(), PHI_ARG_DEF, PHI_CHAIN, phi_nodes(), PHI_RESULT, single_imm_use(), TREE_CODE, and tree_forwarder_block_p(). { basic_block *worklist = XNEWVEC (basic_block, n_basic_blocks); basic_block *current = worklist; basic_block bb; calculate_dominance_info (CDI_DOMINATORS); /* Find all PHI nodes that we may be able to merge. */ FOR_EACH_BB (bb) { basic_block dest; /* Look for a forwarder block with PHI nodes. */ if (!tree_forwarder_block_p (bb, true)) continue; dest = single_succ (bb); /* We have to feed into another basic block with PHI nodes. */ if (!phi_nodes (dest) /* We don't want to deal with a basic block with abnormal edges. */ || has_abnormal_incoming_edge_p (bb)) continue; if (!dominated_by_p (CDI_DOMINATORS, dest, bb)) { /* If BB does not dominate DEST, then the PHI nodes at DEST must be the only users of the results of the PHI nodes at BB. */ *current++ = bb; } else { tree phi; unsigned int dest_idx = single_succ_edge (bb)->dest_idx; /* BB dominates DEST. There may be many users of the PHI nodes in BB. However, there is still a trivial case we can handle. If the result of every PHI in BB is used only by a PHI in DEST, then we can trivially merge the PHI nodes from BB into DEST. */ for (phi = phi_nodes (bb); phi; phi = PHI_CHAIN (phi)) { tree result = PHI_RESULT (phi); use_operand_p imm_use; tree use_stmt; /* If the PHI's result is never used, then we can just ignore it. */ if (has_zero_uses (result)) continue; /* Get the single use of the result of this PHI node. */ if (!single_imm_use (result, &imm_use, &use_stmt) || TREE_CODE (use_stmt) != PHI_NODE || bb_for_stmt (use_stmt) != dest || PHI_ARG_DEF (use_stmt, dest_idx) != result) break; } /* If the loop above iterated through all the PHI nodes in BB, then we can merge the PHIs from BB into DEST. */ if (!phi) *current++ = bb; } } /* Now let's drain WORKLIST. */ while (current != worklist) { bb = *--current; remove_forwarder_block_with_phi (bb); } free (worklist); return 0; }

static bool phi_alternatives_equal (   )  [static]

If all the PHI nodes in DEST have alternatives for E1 and E2 and those alternatives are equal in each of the PHI nodes, then return true, else return false. Definition at line 335 of file tree-cfgcleanup.c. References NULL_TREE, operand_equal_for_phi_arg_p(), PHI_ARG_DEF, PHI_CHAIN, and phi_nodes(). Referenced by remove_forwarder_block(), and remove_forwarder_block_with_phi(). { int n1 = e1->dest_idx; int n2 = e2->dest_idx; tree phi; for (phi = phi_nodes (dest); phi; phi = PHI_CHAIN (phi)) { tree val1 = PHI_ARG_DEF (phi, n1); tree val2 = PHI_ARG_DEF (phi, n2); gcc_assert (val1 != NULL_TREE); gcc_assert (val2 != NULL_TREE); if (!operand_equal_for_phi_arg_p (val1, val2)) return false; } return true; }

static bool remove_fallthru_edge (  VEC(edge, gc)*  ev  )  [static]

Remove any fallthru edge from EV. Return true if an edge was removed. Definition at line 53 of file tree-cfgcleanup.c. { edge_iterator ei; edge e; FOR_EACH_EDGE (e, ei, ev) if ((e->flags & EDGE_FALLTHRU) != 0) { remove_edge (e); return true; } return false; }

static bool remove_forwarder_block (   )  [static]

Removes forwarder block BB. Returns false if this failed. If a new forwarder block is created due to redirection of edges, it is stored to worklist. Definition at line 361 of file tree-cfgcleanup.c. References DECL_NONLOCAL, first_stmt(), has_abnormal_incoming_edge_p(), LABEL_EXPR_LABEL, NULL_TREE, phi_alternatives_equal(), phi_nodes(), and TREE_CODE. Referenced by cleanup_forwarder_blocks(). { edge succ = single_succ_edge (bb), e, s; basic_block dest = succ->dest; tree label; tree phi; edge_iterator ei; block_stmt_iterator bsi, bsi_to; bool seen_abnormal_edge = false; /* We check for infinite loops already in tree_forwarder_block_p. However it may happen that the infinite loop is created afterwards due to removal of forwarders. */ if (dest == bb) return false; /* If the destination block consists of a nonlocal label, do not merge it. */ label = first_stmt (dest); if (label && TREE_CODE (label) == LABEL_EXPR && DECL_NONLOCAL (LABEL_EXPR_LABEL (label))) return false; /* If there is an abnormal edge to basic block BB, but not into dest, problems might occur during removal of the phi node at out of ssa due to overlapping live ranges of registers. If there is an abnormal edge in DEST, the problems would occur anyway since cleanup_dead_labels would then merge the labels for two different eh regions, and rest of exception handling code does not like it. So if there is an abnormal edge to BB, proceed only if there is no abnormal edge to DEST and there are no phi nodes in DEST. */ if (has_abnormal_incoming_edge_p (bb)) { seen_abnormal_edge = true; if (has_abnormal_incoming_edge_p (dest) || phi_nodes (dest) != NULL_TREE) return false; } /* If there are phi nodes in DEST, and some of the blocks that are predecessors of BB are also predecessors of DEST, check that the phi node arguments match. */ if (phi_nodes (dest)) { FOR_EACH_EDGE (e, ei, bb->preds) { s = find_edge (e->src, dest); if (!s) continue; if (!phi_alternatives_equal (dest, succ, s)) return false; } } /* Redirect the edges. */ for (ei = ei_start (bb->preds); (e = ei_safe_edge (ei)); ) { if (e->flags & EDGE_ABNORMAL) { /* If there is an abnormal edge, redirect it anyway, and move the labels to the new block to make it legal. */ s = redirect_edge_succ_nodup (e, dest); } else s = redirect_edge_and_branch (e, dest); if (s == e) { /* Create arguments for the phi nodes, since the edge was not here before. */ for (phi = phi_nodes (dest); phi; phi = PHI_CHAIN (phi)) add_phi_arg (phi, PHI_ARG_DEF (phi, succ->dest_idx), s); } else { /* The source basic block might become a forwarder. We know that it was not a forwarder before, since it used to have at least two outgoing edges, so we may just add it to worklist. */ if (tree_forwarder_block_p (s->src, false)) *(*worklist)++ = s->src; } } if (seen_abnormal_edge) { /* Move the labels to the new block, so that the redirection of the abnormal edges works. */ bsi_to = bsi_start (dest); for (bsi = bsi_start (bb); !bsi_end_p (bsi); ) { label = bsi_stmt (bsi); gcc_assert (TREE_CODE (label) == LABEL_EXPR); bsi_remove (&bsi, false); bsi_insert_before (&bsi_to, label, BSI_CONTINUE_LINKING); } } /* Update the dominators. */ if (dom_info_available_p (CDI_DOMINATORS)) { basic_block dom, dombb, domdest; dombb = get_immediate_dominator (CDI_DOMINATORS, bb); domdest = get_immediate_dominator (CDI_DOMINATORS, dest); if (domdest == bb) { /* Shortcut to avoid calling (relatively expensive) nearest_common_dominator unless necessary. */ dom = dombb; } else dom = nearest_common_dominator (CDI_DOMINATORS, domdest, dombb); set_immediate_dominator (CDI_DOMINATORS, dest, dom); } /* And kill the forwarder block. */ delete_basic_block (bb); return true; }

static void remove_forwarder_block_with_phi (   )  [static]

Merge the PHI nodes at BB into those at BB's sole successor. Definition at line 612 of file tree-cfgcleanup.c. References add_phi_arg(), DECL_NONLOCAL, first_stmt(), LABEL_EXPR_LABEL, NULL_TREE, PENDING_STMT, phi_alternatives_equal(), PHI_ARG_DEF, PHI_CHAIN, phi_nodes(), TREE_CHAIN, TREE_CODE, TREE_PURPOSE, and TREE_VALUE. { edge succ = single_succ_edge (bb); basic_block dest = succ->dest; tree label; basic_block dombb, domdest, dom; /* We check for infinite loops already in tree_forwarder_block_p. However it may happen that the infinite loop is created afterwards due to removal of forwarders. */ if (dest == bb) return; /* If the destination block consists of a nonlocal label, do not merge it. */ label = first_stmt (dest); if (label && TREE_CODE (label) == LABEL_EXPR && DECL_NONLOCAL (LABEL_EXPR_LABEL (label))) return; /* Redirect each incoming edge to BB to DEST. */ while (EDGE_COUNT (bb->preds) > 0) { edge e = EDGE_PRED (bb, 0), s; tree phi; s = find_edge (e->src, dest); if (s) { /* We already have an edge S from E->src to DEST. If S and E->dest's sole successor edge have the same PHI arguments at DEST, redirect S to DEST. */ if (phi_alternatives_equal (dest, s, succ)) { e = redirect_edge_and_branch (e, dest); PENDING_STMT (e) = NULL_TREE; continue; } /* PHI arguments are different. Create a forwarder block by splitting E so that we can merge PHI arguments on E to DEST. */ e = single_succ_edge (split_edge (e)); } s = redirect_edge_and_branch (e, dest); /* redirect_edge_and_branch must not create a new edge. */ gcc_assert (s == e); /* Add to the PHI nodes at DEST each PHI argument removed at the destination of E. */ for (phi = phi_nodes (dest); phi; phi = PHI_CHAIN (phi)) { tree def = PHI_ARG_DEF (phi, succ->dest_idx); if (TREE_CODE (def) == SSA_NAME) { tree var; /* If DEF is one of the results of PHI nodes removed during redirection, replace it with the PHI argument that used to be on E. */ for (var = PENDING_STMT (e); var; var = TREE_CHAIN (var)) { tree old_arg = TREE_PURPOSE (var); tree new_arg = TREE_VALUE (var); if (def == old_arg) { def = new_arg; break; } } } add_phi_arg (phi, def, s); } PENDING_STMT (e) = NULL; } /* Update the dominators. */ dombb = get_immediate_dominator (CDI_DOMINATORS, bb); domdest = get_immediate_dominator (CDI_DOMINATORS, dest); if (domdest == bb) { /* Shortcut to avoid calling (relatively expensive) nearest_common_dominator unless necessary. */ dom = dombb; } else dom = nearest_common_dominator (CDI_DOMINATORS, domdest, dombb); set_immediate_dominator (CDI_DOMINATORS, dest, dom); /* Remove BB since all of BB's incoming edges have been redirected to DEST. */ delete_basic_block (bb); }

static bool tree_forwarder_block_p (   )  [static]

Return true if basic block BB does nothing except pass control flow to another block and that we can safely insert a label at the start of the successor block. As a precondition, we require that BB be not equal to ENTRY_BLOCK_PTR. Definition at line 239 of file tree-cfgcleanup.c. References bsi_end_p(), bsi_last, bsi_prev(), bsi_stmt(), DECL_NONLOCAL, LABEL_EXPR_LABEL, NULL_TREE, phi_nodes(), and TREE_CODE. Referenced by cleanup_forwarder_blocks(), and merge_phi_nodes(). { block_stmt_iterator bsi; edge_iterator ei; edge e, succ; basic_block dest; /* BB must have a single outgoing edge. */ if (single_succ_p (bb) != 1 /* If PHI_WANTED is false, BB must not have any PHI nodes. Otherwise, BB must have PHI nodes. */ || (phi_nodes (bb) != NULL_TREE) != phi_wanted /* BB may not be a predecessor of EXIT_BLOCK_PTR. */ || single_succ (bb) == EXIT_BLOCK_PTR /* Nor should this be an infinite loop. */ || single_succ (bb) == bb /* BB may not have an abnormal outgoing edge. */ || (single_succ_edge (bb)->flags & EDGE_ABNORMAL)) return false; #if ENABLE_CHECKING gcc_assert (bb != ENTRY_BLOCK_PTR); #endif /* Now walk through the statements backward. We can ignore labels, anything else means this is not a forwarder block. */ for (bsi = bsi_last (bb); !bsi_end_p (bsi); bsi_prev (&bsi)) { tree stmt = bsi_stmt (bsi); switch (TREE_CODE (stmt)) { case LABEL_EXPR: if (DECL_NONLOCAL (LABEL_EXPR_LABEL (stmt))) return false; break; default: return false; } } if (find_edge (ENTRY_BLOCK_PTR, bb)) return false; if (current_loops) { basic_block dest; /* Protect loop latches, headers and preheaders. */ if (bb->loop_father->header == bb) return false; dest = EDGE_SUCC (bb, 0)->dest; if (dest->loop_father->header == dest) return false; } /* If we have an EH edge leaving this block, make sure that the destination of this block has only one predecessor. This ensures that we don't get into the situation where we try to remove two forwarders that go to the same basic block but are handlers for different EH regions. */ succ = single_succ_edge (bb); dest = succ->dest; FOR_EACH_EDGE (e, ei, bb->preds) { if (e->flags & EDGE_EH) { if (!single_pred_p (dest)) return false; } } return true; }

VEC (  tree  , gc  )  [inline]

Try to remove superfluous control structures. Definition at line 136 of file tree-cfgcleanup.c. Referenced by access_functions_are_affine_or_constant_p(), add_graph_edge(), add_may_alias_for_new_tag(), add_virtual_operand(), allocate_graph_weights(), analyze_array(), build_constraint_graph(), build_constructor_from_list(), build_constructor_single(), build_tree_conflict_graph(), clear_edges_for_node(), compute_antic_aux(), compute_call_clobbered(), compute_data_dependences_for_loop(), compute_tag_properties(), compute_vuse_representatives(), create_name_tags(), create_overlap_variables_for(), create_structure_vars(), create_variable_info_for(), dequeue_and_dump(), do_structure_copy(), dump_may_aliases_for(), erase_graph_self_edge(), expand_vector_piecewise(), find_func_aliases(), find_idf(), get_graph_weights(), gimplify_compound_lval(), gimplify_init_constructor(), gimplify_init_ctor_preeval(), gimplify_switch_expr(), handle_ptr_arith(), init_data_ref(), is_aliased_with(), linear_transform_loops(), mark_aliases_call_clobbered(), merge_graph_nodes(), move_sese_region_to_fn(), new_type_alias(), perform_var_substitution(), phi_translate(), phi_translate_set(), prune_unused_phi_nodes(), reassociate_bb(), recalculate_used_alone(), remove_dead_inserted_code(), scev_analysis(), setup_pointers_and_addressables(), simple_cst_equal(), solve_graph(), topo_visit(), VEC(), vect_analyze_data_ref_accesses(), vect_analyze_data_ref_dependences(), vect_analyze_data_refs(), vect_compute_data_refs_alignment(), vect_create_cond_for_align_checks(), vect_enhance_data_refs_alignment(), vect_mark_stmts_to_be_vectorized(), vect_update_inits_of_drs(), vect_update_misalignment_for_peel(), vect_verify_datarefs_alignment(), verify_flow_insensitive_alias_info(), verify_name_tags(), and vn_lookup_or_add(). { basic_block bb; block_stmt_iterator bsi; bool retval = false; tree stmt; /* Detect cases where a mid-block call is now known not to return. */ while (VEC_length (tree, modified_noreturn_calls)) { stmt = VEC_pop (tree, modified_noreturn_calls); bb = bb_for_stmt (stmt); if (bb != NULL && last_stmt (bb) != stmt && noreturn_call_p (stmt)) split_block (bb, stmt); } FOR_EACH_BB (bb) { bsi = bsi_last (bb); /* If the last statement of the block could throw and now cannot, we need to prune cfg. */ tree_purge_dead_eh_edges (bb); if (bsi_end_p (bsi)) continue; stmt = bsi_stmt (bsi); if (TREE_CODE (stmt) == COND_EXPR || TREE_CODE (stmt) == SWITCH_EXPR) retval |= cleanup_control_expr_graph (bb, bsi); /* If we had a computed goto which has a compile-time determinable destination, then we can eliminate the goto. */ else if (TREE_CODE (stmt) == GOTO_EXPR && TREE_CODE (GOTO_DESTINATION (stmt)) == ADDR_EXPR && (TREE_CODE (TREE_OPERAND (GOTO_DESTINATION (stmt), 0)) == LABEL_DECL)) { edge e; tree label; edge_iterator ei; basic_block target_block; bool removed_edge = false; /* First look at all the outgoing edges. Delete any outgoing edges which do not go to the right block. For the one edge which goes to the right block, fix up its flags. */ label = TREE_OPERAND (GOTO_DESTINATION (stmt), 0); target_block = label_to_block (label); for (ei = ei_start (bb->succs); (e = ei_safe_edge (ei)); ) { if (e->dest != target_block) { removed_edge = true; remove_edge (e); } else { /* Turn off the EDGE_ABNORMAL flag. */ e->flags &= ~EDGE_ABNORMAL; /* And set EDGE_FALLTHRU. */ e->flags |= EDGE_FALLTHRU; ei_next (&ei); } } /* If we removed one or more edges, then we will need to fix the dominators. It may be possible to incrementally update them. */ if (removed_edge) free_dominance_info (CDI_DOMINATORS); /* Remove the GOTO_EXPR as it is not needed. The CFG has all the relevant information we need. */ bsi_remove (&bsi, true); retval = true; } /* Check for indirect calls that have been turned into noreturn calls. */ else if (noreturn_call_p (stmt) && remove_fallthru_edge (bb->succs)) { free_dominance_info (CDI_DOMINATORS); retval = true; } } return retval; }

---

Variable Documentation

struct tree_opt_pass pass_merge_phi

Initial value: { "mergephi", gate_merge_phi, merge_phi_nodes, NULL, NULL, 0, TV_TREE_MERGE_PHI, PROP_cfg | PROP_ssa, 0, 0, 0, TODO_dump_func | TODO_ggc_collect | TODO_verify_ssa, 0 } Definition at line 827 of file tree-cfgcleanup.c.

---