This commit was generated by cvs2svn to compensate for changes in r132718,

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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
+}