invoke.texi (-fprefetch-loop-arrays, [...]): Document.

	* doc/invoke.texi (-fprefetch-loop-arrays, -fprefetch-loop-arrays-rtl):
	Document.
	* tree-ssa-loop-niter.c (number_of_iterations_ne,
	number_of_iterations_lt, number_of_iterations_cond): Remember the shape
	of the ending condition.
	* tree-ssa-loop-manip.c: Include params.h.
	(build_if_stmt, can_unroll_loop_p, determine_exit_conditions,
	tree_unroll_loop): New functions.
	* tree-pass.h (pass_loop_prefetch): Declare.
	* loop.c (rest_of_handle_loop_optimize): Test for
	-fprefetch-loop-arrays-rtl.
	* tree-scalar-evolution.h (affine_iv): Moved to tree-flow.h.
	* timevar.def (TV_TREE_PREFETCH): New timevar.
	* tree-ssa-loop.c (tree_ssa_loop_prefetch, gate_tree_ssa_loop_prefetch,
	pass_loop_prefetch): New.
	* tree-cfgcleanup.c: Include tree-scalar-evolution.h.
	(cleanup_tree_cfg_loop): Call scev_reset.
	* common.opt (fprefetch-loop-arrays-rtl): Add.
	* tree-ssa-loop-prefetch.c: New file.
	* tree-outof-ssa.c (struct value_expr_d): Add expr_vars field.
	(new_temp_expr_table): Initialize expr_vars.
	(free_temp_expr_table): Cleanup expr_vars.
	(check_replaceable, find_replaceable_in_bb): Prevent accumulating
	expressions from being merged into one.
	* tree-flow.h (affine_iv): Moved from tree-scalar-evolution.h.
	(struct tree_niter_desc): Add control, bound and cmp fields.
	(tree_ssa_prefetch_arrays, can_unroll_loop_p, tree_unroll_loop):
	Declare.
	* Makefile.in (tree-ssa-loop-prefetch.o): Add.
	(tree-cfgcleanup.o): Add SCEV_H dependency.
	(tree-ssa-loop-manip.o): Add PARAMS_H dependency.
	* passes.c (init_optimization_passes): Add pass_loop_prefetch.

From-SVN: r110964

1 files changed, 15 insertions, 11 deletions

diff --git a/gcc/tree-cfgcleanup.c b/gcc/tree-cfgcleanup.c
index 4619d1d..76667a6 100644
--- a/gcc/tree-cfgcleanup.c
+++ b/gcc/tree-cfgcleanup.c
@@ -45,6 +45,7 @@ Boston, MA 02110-1301, USA.  */
 #include "cfglayout.h"
 #include "hashtab.h"
 #include "tree-ssa-propagate.h"
+#include "tree-scalar-evolution.h"
 
 /* Remove any fallthru edge from EV.  Return true if an edge was removed.  */
 
@@ -559,23 +560,26 @@ cleanup_tree_cfg (void)
 void
 cleanup_tree_cfg_loop (void)
 {
-  bitmap changed_bbs = BITMAP_ALLOC (NULL);
+  bool changed = cleanup_tree_cfg ();
 
-  cleanup_tree_cfg ();
-
-  fix_loop_structure (current_loops, changed_bbs);
-  calculate_dominance_info (CDI_DOMINATORS);
+  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);
+      /* 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);
+      BITMAP_FREE (changed_bbs);
 
 #ifdef ENABLE_CHECKING
-  verify_loop_structure (current_loops);
+      verify_loop_structure (current_loops);
 #endif
+      scev_reset ();
+    }
 }
 
 /* Merge the PHI nodes at BB into those at BB's sole successor.  */