[PATCH] Limit path splitting to loops we optimize for speed

	* doc/invoke.texi (-O2 options): Remove -fsplit-paths.
	(-O3 options): Add -fsplit-paths.
	* gimple-ssa-split-paths.c: Include predict.h
	(split_paths): Only split paths in a loop that should be
	optimized for speed.
	* opts.c (default_options_table): Move -fsplit-paths from -O2 to
	-O3.

	* gcc.dg/tree-ssa/split-path-1.c: Explicitly ask for path
	splitting optimizations.

From-SVN: r231790

1 files changed, 7 insertions, 1 deletions

diff --git a/gcc/gimple-ssa-split-paths.c b/gcc/gimple-ssa-split-paths.c
index 602e916..540fdf3 100644
--- a/gcc/gimple-ssa-split-paths.c
+++ b/gcc/gimple-ssa-split-paths.c
@@ -29,6 +29,7 @@ along with GCC; see the file COPYING3.  If not see
 #include "cfgloop.h"
 #include "gimple-iterator.h"
 #include "tracer.h"
+#include "predict.h"
 
 /* Given LATCH, the latch block in a loop, see if the shape of the
    path reaching LATCH is suitable for being split by duplication.
@@ -180,9 +181,14 @@ split_paths ()
 
   FOR_EACH_LOOP (loop, LI_FROM_INNERMOST)
     {
+      /* Only split paths if we are optimizing this loop for speed.  */
+      if (!optimize_loop_for_speed_p (loop))
+	continue;
+
       /* See if there is a block that we can duplicate to split the
 	 path to the loop latch.  */
-      basic_block bb = find_block_to_duplicate_for_splitting_paths (loop->latch);
+      basic_block bb
+	= find_block_to_duplicate_for_splitting_paths (loop->latch);
 
       /* BB is the merge point for an IF-THEN-ELSE we want to transform.