re PR middle-end/30905 (Fails to cross-jump)
2008-01-11 Steven Bosscher <stevenb.gcc@gmail.com> PR rtl-optimization/30905 * cfgcleanup.c: Include dce.h (crossjumps_occured): New global variable. (try_crossjump_bb): Exit loop after finding a fallthru edge. If something changed, set crossjumps_occured to true. (try_optimize_cfg): Clear crossjumps_occured at the beginning. Don't add/remove fake edges to exit here... (cleanup_cfg): ...but do it here, when crossjumping. Run a fast DCE when successful crossjumps occured in the latest iteration of try_optimize_cfg. From-SVN: r131468
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Steven Bosscher
Richard Biener
parent
8d0eca24fa
commit
c1e3e2d944
2 changed files with 57 additions and 12 deletions
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@ -1,3 +1,16 @@
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2008-01-11 Steven Bosscher <stevenb.gcc@gmail.com>
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PR rtl-optimization/30905
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* cfgcleanup.c: Include dce.h
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(crossjumps_occured): New global variable.
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(try_crossjump_bb): Exit loop after finding a fallthru edge.
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If something changed, set crossjumps_occured to true.
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(try_optimize_cfg): Clear crossjumps_occured at the beginning.
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Don't add/remove fake edges to exit here...
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(cleanup_cfg): ...but do it here, when crossjumping.
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Run a fast DCE when successful crossjumps occured in the latest
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iteration of try_optimize_cfg.
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2008-01-11 Richard Guenther <rguenther@suse.de>
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* tree-ssa-sccvn.c (struct vn_binary_op_s): Move hashcode near opcode.
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@ -54,11 +54,16 @@ along with GCC; see the file COPYING3. If not see
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#include "cfgloop.h"
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#include "expr.h"
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#include "df.h"
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#include "dce.h"
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#define FORWARDER_BLOCK_P(BB) ((BB)->flags & BB_FORWARDER_BLOCK)
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/* Set to true when we are running first pass of try_optimize_cfg loop. */
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static bool first_pass;
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/* Set to true if crossjumps occured in the latest run of try_optimize_cfg. */
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static bool crossjumps_occured;
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static bool try_crossjump_to_edge (int, edge, edge);
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static bool try_crossjump_bb (int, basic_block);
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static bool outgoing_edges_match (int, basic_block, basic_block);
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@ -1838,7 +1843,10 @@ try_crossjump_bb (int mode, basic_block bb)
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FOR_EACH_EDGE (e, ei, bb->preds)
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{
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if (e->flags & EDGE_FALLTHRU)
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fallthru = e;
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{
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fallthru = e;
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break;
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}
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}
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changed = false;
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@ -1847,7 +1855,8 @@ try_crossjump_bb (int mode, basic_block bb)
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e = EDGE_PRED (ev, ix);
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ix++;
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/* As noted above, first try with the fallthru predecessor. */
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/* As noted above, first try with the fallthru predecessor (or, a
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fallthru predecessor if we are in cfglayout mode). */
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if (fallthru)
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{
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/* Don't combine the fallthru edge into anything else.
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@ -1921,6 +1930,9 @@ try_crossjump_bb (int mode, basic_block bb)
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}
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}
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if (changed)
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crossjumps_occured = true;
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return changed;
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}
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@ -1935,12 +1947,11 @@ try_optimize_cfg (int mode)
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int iterations = 0;
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basic_block bb, b, next;
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if (mode & CLEANUP_CROSSJUMP)
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add_noreturn_fake_exit_edges ();
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if (mode & (CLEANUP_CROSSJUMP | CLEANUP_THREADING))
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clear_bb_flags ();
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crossjumps_occured = false;
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FOR_EACH_BB (bb)
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update_forwarder_flag (bb);
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@ -2131,9 +2142,6 @@ try_optimize_cfg (int mode)
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while (changed);
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}
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if (mode & CLEANUP_CROSSJUMP)
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remove_fake_exit_edges ();
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FOR_ALL_BB (b)
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b->flags &= ~(BB_FORWARDER_BLOCK | BB_NONTHREADABLE_BLOCK);
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@ -2235,20 +2243,44 @@ cleanup_cfg (int mode)
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compact_blocks ();
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/* To tail-merge blocks ending in the same noreturn function (e.g.
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a call to abort) we have to insert fake edges to exit. Do this
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here once. The fake edges do not interfere with any other CFG
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cleanups. */
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if (mode & CLEANUP_CROSSJUMP)
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add_noreturn_fake_exit_edges ();
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while (try_optimize_cfg (mode))
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{
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delete_unreachable_blocks (), changed = true;
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if (!(mode & CLEANUP_NO_INSN_DEL)
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&& (mode & CLEANUP_EXPENSIVE)
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&& !reload_completed)
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if (!(mode & CLEANUP_NO_INSN_DEL))
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{
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if (!delete_trivially_dead_insns (get_insns (), max_reg_num ()))
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/* Try to remove some trivially dead insns when doing an expensive
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cleanup. But delete_trivially_dead_insns doesn't work after
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reload (it only handles pseudos) and run_fast_dce is too costly
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to run in every iteration.
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For effective cross jumping, we really want to run a fast DCE to
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clean up any dead conditions, or they get in the way of performing
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useful tail merges.
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Other transformations in cleanup_cfg are not so sensitive to dead
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code, so delete_trivially_dead_insns or even doing nothing at all
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is good enough. */
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if ((mode & CLEANUP_EXPENSIVE) && !reload_completed
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&& !delete_trivially_dead_insns (get_insns (), max_reg_num ()))
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break;
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else if ((mode & CLEANUP_CROSSJUMP)
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&& crossjumps_occured)
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run_fast_dce ();
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}
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else
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break;
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}
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if (mode & CLEANUP_CROSSJUMP)
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remove_fake_exit_edges ();
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/* Don't call delete_dead_jumptables in cfglayout mode, because
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that function assumes that jump tables are in the insns stream.
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But we also don't _have_ to delete dead jumptables in cfglayout
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