diff options
Diffstat (limited to 'gcc/loop-init.c')
| -rw-r--r-- | gcc/loop-init.c | 155 |
1 files changed, 126 insertions, 29 deletions
diff --git a/gcc/loop-init.c b/gcc/loop-init.c index 7e33de0..d64c110 100644 --- a/gcc/loop-init.c +++ b/gcc/loop-init.c @@ -32,37 +32,11 @@ along with GCC; see the file COPYING3. If not see #include "ggc.h" -/* Initialize loop structures. This is used by the tree and RTL loop - optimizers. FLAGS specify what properties to compute and/or ensure for - loops. */ +/* Apply FLAGS to the loop state. */ -void -loop_optimizer_init (unsigned flags) +static void +apply_loop_flags (unsigned flags) { - timevar_push (TV_LOOP_INIT); - if (!current_loops) - { - struct loops *loops = ggc_alloc_cleared_loops (); - - gcc_assert (!(cfun->curr_properties & PROP_loops)); - - /* Find the loops. */ - - flow_loops_find (loops); - current_loops = loops; - } - else - { - gcc_assert (cfun->curr_properties & PROP_loops); - - /* Ensure that the dominators are computed, like flow_loops_find does. */ - calculate_dominance_info (CDI_DOMINATORS); - -#ifdef ENABLE_CHECKING - verify_loop_structure (); -#endif - } - if (flags & LOOPS_MAY_HAVE_MULTIPLE_LATCHES) { /* If the loops may have multiple latches, we cannot canonicalize @@ -97,6 +71,38 @@ loop_optimizer_init (unsigned flags) if (flags & LOOPS_HAVE_RECORDED_EXITS) record_loop_exits (); +} + +/* Initialize loop structures. This is used by the tree and RTL loop + optimizers. FLAGS specify what properties to compute and/or ensure for + loops. */ + +void +loop_optimizer_init (unsigned flags) +{ + timevar_push (TV_LOOP_INIT); + + if (!current_loops) + { + gcc_assert (!(cfun->curr_properties & PROP_loops)); + + /* Find the loops. */ + current_loops = flow_loops_find (NULL); + } + else + { + gcc_assert (cfun->curr_properties & PROP_loops); + + /* Ensure that the dominators are computed, like flow_loops_find does. */ + calculate_dominance_info (CDI_DOMINATORS); + +#ifdef ENABLE_CHECKING + verify_loop_structure (); +#endif + } + + /* Apply flags to loops. */ + apply_loop_flags (flags); /* Dump loops. */ flow_loops_dump (dump_file, NULL, 1); @@ -157,6 +163,97 @@ loop_fini_done: timevar_pop (TV_LOOP_FINI); } +/* The structure of loops might have changed. Some loops might get removed + (and their headers and latches were set to NULL), loop exists might get + removed (thus the loop nesting may be wrong), and some blocks and edges + were changed (so the information about bb --> loop mapping does not have + to be correct). But still for the remaining loops the header dominates + the latch, and loops did not get new subloops (new loops might possibly + get created, but we are not interested in them). Fix up the mess. + + If CHANGED_BBS is not NULL, basic blocks whose loop has changed are + marked in it. */ + +void +fix_loop_structure (bitmap changed_bbs) +{ + basic_block bb; + int record_exits = 0; + loop_iterator li; + struct loop *loop; + + timevar_push (TV_LOOP_INIT); + + /* We need exact and fast dominance info to be available. */ + gcc_assert (dom_info_state (CDI_DOMINATORS) == DOM_OK); + + if (loops_state_satisfies_p (LOOPS_HAVE_RECORDED_EXITS)) + { + release_recorded_exits (); + record_exits = LOOPS_HAVE_RECORDED_EXITS; + } + + /* Remember the depth of the blocks in the loop hierarchy, so that we can + recognize blocks whose loop nesting relationship has changed. */ + if (changed_bbs) + FOR_EACH_BB (bb) + bb->aux = (void *) (size_t) loop_depth (bb->loop_father); + + /* Remove the dead loops from structures. We start from the innermost + loops, so that when we remove the loops, we know that the loops inside + are preserved, and do not waste time relinking loops that will be + removed later. */ + FOR_EACH_LOOP (li, loop, LI_FROM_INNERMOST) + { + /* Detect the case that the loop is no longer present even though + it wasn't marked for removal. + ??? If we do that we can get away with not marking loops for + removal at all. And possibly avoid some spurious removals. */ + if (loop->header + && bb_loop_header_p (loop->header)) + continue; + + if (dump_file && (dump_flags & TDF_DETAILS)) + fprintf (dump_file, "fix_loop_structure: removing loop %d\n", + loop->num); + + while (loop->inner) + { + struct loop *ploop = loop->inner; + flow_loop_tree_node_remove (ploop); + flow_loop_tree_node_add (loop_outer (loop), ploop); + } + + /* Remove the loop and free its data. */ + delete_loop (loop); + } + + /* Re-compute loop structure in-place. */ + flow_loops_find (current_loops); + + /* Mark the blocks whose loop has changed. */ + if (changed_bbs) + { + FOR_EACH_BB (bb) + { + if ((void *) (size_t) loop_depth (bb->loop_father) != bb->aux) + bitmap_set_bit (changed_bbs, bb->index); + + bb->aux = NULL; + } + } + + loops_state_clear (LOOPS_NEED_FIXUP); + + /* Apply flags to loops. */ + apply_loop_flags (current_loops->state | record_exits); + +#ifdef ENABLE_CHECKING + verify_loop_structure (); +#endif + + timevar_pop (TV_LOOP_INIT); +} /* Gate for the RTL loop superpass. The actual passes are subpasses. See passes.c for more on that. */ |