diff options
Diffstat (limited to 'contrib/gcc/loop-init.c')
-rw-r--r-- | contrib/gcc/loop-init.c | 220 |
1 files changed, 220 insertions, 0 deletions
diff --git a/contrib/gcc/loop-init.c b/contrib/gcc/loop-init.c new file mode 100644 index 0000000..6dd146f --- /dev/null +++ b/contrib/gcc/loop-init.c @@ -0,0 +1,220 @@ +/* Loop optimizer initialization routines. + Copyright (C) 2002, 2003, 2004 Free Software Foundation, Inc. + +This file is part of GCC. + +GCC is free software; you can redistribute it and/or modify it under +the terms of the GNU General Public License as published by the Free +Software Foundation; either version 2, or (at your option) any later +version. + +GCC is distributed in the hope that it will be useful, but WITHOUT ANY +WARRANTY; without even the implied warranty of MERCHANTABILITY or +FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License +for more details. + +You should have received a copy of the GNU General Public License +along with GCC; see the file COPYING. If not, write to the Free +Software Foundation, 59 Temple Place - Suite 330, Boston, MA +02111-1307, USA. */ + +#include "config.h" +#include "system.h" +#include "coretypes.h" +#include "tm.h" +#include "rtl.h" +#include "hard-reg-set.h" +#include "basic-block.h" +#include "cfgloop.h" +#include "cfglayout.h" + +static void fixup_loop_exit_succesor (basic_block, basic_block); + +/* Initialize loop optimizer. */ + +struct loops * +loop_optimizer_init (FILE *dumpfile) +{ + struct loops *loops = xcalloc (1, sizeof (struct loops)); + edge e; + + /* Initialize structures for layout changes. */ + cfg_layout_initialize (0); + + /* Avoid annoying special cases of edges going to exit + block. */ + for (e = EXIT_BLOCK_PTR->pred; e; e = e->pred_next) + if ((e->flags & EDGE_FALLTHRU) && e->src->succ->succ_next) + split_edge (e); + + /* Find the loops. */ + + if (flow_loops_find (loops, LOOP_TREE) <= 1) + { + basic_block bb; + + /* No loops. */ + flow_loops_free (loops); + free_dominance_info (CDI_DOMINATORS); + free (loops); + + /* Make chain. */ + FOR_EACH_BB (bb) + if (bb->next_bb != EXIT_BLOCK_PTR) + bb->rbi->next = bb->next_bb; + cfg_layout_finalize (); + return NULL; + } + + /* Not going to update these. */ + free (loops->cfg.rc_order); + loops->cfg.rc_order = NULL; + free (loops->cfg.dfs_order); + loops->cfg.dfs_order = NULL; + + /* Create pre-headers. */ + create_preheaders (loops, CP_SIMPLE_PREHEADERS); + + /* Force all latches to have only single successor. */ + force_single_succ_latches (loops); + + /* Mark irreducible loops. */ + mark_irreducible_loops (loops); + + /* Dump loops. */ + flow_loops_dump (loops, dumpfile, NULL, 1); + +#ifdef ENABLE_CHECKING + verify_dominators (CDI_DOMINATORS); + verify_loop_structure (loops); +#endif + + return loops; +} + +/* The first basic block is moved after the second in the reorder chain. */ +static void +fixup_loop_exit_succesor (basic_block exit_succ, basic_block latch) +{ + basic_block bb = exit_succ; + basic_block bb1 = latch; + + if (!(bb && bb->rbi->next)) + return; + + if (!bb1) + return; + + + if (bb && bb->rbi->next) + { + basic_block c = ENTRY_BLOCK_PTR->next_bb; + + while (c->rbi->next != bb) + c = c->rbi->next; + + c->rbi->next = bb->rbi->next; + } + + if(bb1->rbi->next == NULL) + { + bb1->rbi->next=bb; + bb->rbi->next=NULL; + } + else + + { + basic_block tmp; + + tmp = bb1->rbi->next; + bb1->rbi->next = bb; + bb->rbi->next = tmp; + } +} + +/* Finalize loop optimizer. */ +void +loop_optimizer_finalize (struct loops *loops, FILE *dumpfile) +{ + basic_block bb; + unsigned int i; + + /* Finalize layout changes. */ + /* Make chain. */ + FOR_EACH_BB (bb) + if (bb->next_bb != EXIT_BLOCK_PTR) + bb->rbi->next = bb->next_bb; + + /* Another dump. */ + flow_loops_dump (loops, dumpfile, NULL, 1); + + /* For loops ending with a branch and count instruction, move the basic + block found before the unrolling on the fallthru path of this branch, + after the unrolled code. This will allow branch simplification. */ + for (i = 1; i < loops->num; i++) + { + struct loop *loop = loops->parray[i]; + struct loop_desc *desc; + basic_block loop_real_latch, bb, bb_exit; + edge e; + + if (loop == NULL) + continue; + if (!loop->simple) + continue; + if (!loop->has_desc) + continue; + + if (loop->lpt_decision.decision != LPT_UNROLL_RUNTIME) + continue; + + desc = &loop->desc; + if (desc == NULL) + continue; + if (loop->latch->pred == NULL) + continue; + + loop_real_latch = loop->latch->pred->src; + + + if (desc->postincr) + continue; + if (!is_bct_cond (BB_END (loop_real_latch))) + continue; + + for (e = loop_real_latch->succ; e ; e = e->succ_next) + if (e->flags & EDGE_FALLTHRU) + break; + + if (e == NULL) + continue; + + bb_exit = e->dest; + + bb = NULL; + + /* Leave the case of the bb_exit falling through to exit to + fixed_fallthru_exit_predecessor */ + for (e = EXIT_BLOCK_PTR->pred; e; e = e->pred_next) + if (e->flags & EDGE_FALLTHRU) + bb = e->src; + + if (bb_exit == bb) + continue; + + fixup_loop_exit_succesor (bb_exit, loop->latch); + } + + /* Clean up. */ + flow_loops_free (loops); + free_dominance_info (CDI_DOMINATORS); + free (loops); + + /* Finalize changes. */ + cfg_layout_finalize (); + + /* Checking. */ +#ifdef ENABLE_CHECKING + verify_flow_info (); +#endif +} |