* tree-ssa-threadbackward.c: Include tree-inline.h

	(profitable_jump_thread_path): Use estimate_num_insns to estimate
	size of copied block; for cold paths reduce duplication.
	(find_jump_threads_backwards): Remove redundant tests.
	(pass_thread_jumps::gate): Enable for -Os.
	* gcc.dg/tree-ssa/ssa-dom-thread-7.c: Update testcase.


git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@239219 138bc75d-0d04-0410-961f-82ee72b054a4

4 files changed, 37 insertions, 15 deletions

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index 8cd9f2aecfd..9f1caad8c02 100644
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,11 @@
+2016-08-07  Jan Hubicka  <hubicka@ucw.cz>
+
+	* tree-ssa-threadbackward.c: Include tree-inline.h
+	(profitable_jump_thread_path): Use estimate_num_insns to estimate
+	size of copied block; for cold paths reduce duplication.
+	(find_jump_threads_backwards): Remove redundant tests.
+	(pass_thread_jumps::gate): Enable for -Os.
+
 2016-08-07  Jakub Jelinek  <jakub@redhat.com>
 
 	PR c/72816
diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog
index edd4b1cab9f..fece69cab09 100644
--- a/gcc/testsuite/ChangeLog
+++ b/gcc/testsuite/ChangeLog
@@ -1,3 +1,7 @@
+2016-08-07  Jan Hubicka  <hubicka@ucw.cz>
+
+	* gcc.dg/tree-ssa/ssa-dom-thread-7.c: Update testcase.
+
 2016-08-07  Jakub Jelinek  <jakub@redhat.com>
 
 	PR c/72816
diff --git a/gcc/testsuite/gcc.dg/tree-ssa/ssa-dom-thread-7.c b/gcc/testsuite/gcc.dg/tree-ssa/ssa-dom-thread-7.c
index 7cd14510724..1a4089fcdfd 100644
--- a/gcc/testsuite/gcc.dg/tree-ssa/ssa-dom-thread-7.c
+++ b/gcc/testsuite/gcc.dg/tree-ssa/ssa-dom-thread-7.c
@@ -1,7 +1,7 @@
 /* { dg-do compile } */
-/* { dg-options "-O2 -fdump-tree-thread1-stats -fdump-tree-thread2-stats -fdump-tree-thread3-stats -fdump-tree-dom3-stats -fdump-tree-vrp2-stats" } */
+/* { dg-options "-O2 -fdump-tree-thread1-stats -fdump-tree-thread2-stats -fdump-tree-thread3-stats -fdump-tree-dom3-stats -fdump-tree-vrp2-stats -fno-guess-branch-probability" } */
 /* { dg-final { scan-tree-dump "Jumps threaded: 16"  "thread1" } } */
-/* { dg-final { scan-tree-dump "Jumps threaded: 11" "thread2" } } */
+/* { dg-final { scan-tree-dump "Jumps threaded: 6" "thread2" } } */
 /* { dg-final { scan-tree-dump "Jumps threaded: 3" "thread3" } } */
 /* { dg-final { scan-tree-dump-not "Jumps threaded"  "dom3" } } */
 /* { dg-final { scan-tree-dump-not "Jumps threaded"  "vrp2" } } */
diff --git a/gcc/tree-ssa-threadbackward.c b/gcc/tree-ssa-threadbackward.c
index 9dd37adf51c..234ce50d10c 100644
--- a/gcc/tree-ssa-threadbackward.c
+++ b/gcc/tree-ssa-threadbackward.c
@@ -35,6 +35,7 @@ along with GCC; see the file COPYING3.  If not see
 #include "tree-pass.h"
 #include "gimple-ssa.h"
 #include "tree-phinodes.h"
+#include "tree-inline.h"
 
 static int max_threaded_paths;
 
@@ -223,7 +224,7 @@ profitable_jump_thread_path (vec<basic_block, va_gc> *&path,
 		  && !(gimple_code (stmt) == GIMPLE_ASSIGN
 		       && gimple_assign_rhs_code (stmt) == ASSERT_EXPR)
 		  && !is_gimple_debug (stmt))
-		++n_insns;
+	        n_insns += estimate_num_insns (stmt, &eni_size_weights);
 	    }
 
 	  /* We do not look at the block with the threaded branch
@@ -251,13 +252,15 @@ profitable_jump_thread_path (vec<basic_block, va_gc> *&path,
 	threaded_through_latch = true;
     }
 
+  gimple *stmt = get_gimple_control_stmt ((*path)[0]);
+  gcc_assert (stmt);
+
   /* We are going to remove the control statement at the end of the
      last block in the threading path.  So don't count it against our
      statement count.  */
-  n_insns--;
 
-  gimple *stmt = get_gimple_control_stmt ((*path)[0]);
-  gcc_assert (stmt);
+  n_insns-= estimate_num_insns (stmt, &eni_size_weights);
+
   /* We have found a constant value for ARG.  For GIMPLE_SWITCH
      and GIMPLE_GOTO, we use it as-is.  However, for a GIMPLE_COND
      we need to substitute, fold and simplify so we can determine
@@ -303,12 +306,24 @@ profitable_jump_thread_path (vec<basic_block, va_gc> *&path,
       return NULL;
     }
 
-  if (n_insns >= PARAM_VALUE (PARAM_MAX_FSM_THREAD_PATH_INSNS))
+  if (optimize_edge_for_speed_p (taken_edge))
+    {
+      if (n_insns >= PARAM_VALUE (PARAM_MAX_FSM_THREAD_PATH_INSNS))
+	{
+	  if (dump_file && (dump_flags & TDF_DETAILS))
+	    fprintf (dump_file, "FSM jump-thread path not considered: "
+		     "the number of instructions on the path "
+		     "exceeds PARAM_MAX_FSM_THREAD_PATH_INSNS.\n");
+	  path->pop ();
+	  return NULL;
+	}
+    }
+  else if (n_insns > 1)
     {
       if (dump_file && (dump_flags & TDF_DETAILS))
 	fprintf (dump_file, "FSM jump-thread path not considered: "
-		 "the number of instructions on the path "
-		 "exceeds PARAM_MAX_FSM_THREAD_PATH_INSNS.\n");
+		 "duplication of %i insns is needed and optimizing for size.\n",
+		 n_insns);
       path->pop ();
       return NULL;
     }
@@ -612,10 +627,6 @@ fsm_find_control_statement_thread_paths (tree name,
 void  
 find_jump_threads_backwards (basic_block bb)
 {     
-  if (!flag_expensive_optimizations
-      || optimize_function_for_size_p (cfun))
-    return;
-
   gimple *stmt = get_gimple_control_stmt (bb);
   if (!stmt)
     return;
@@ -680,8 +691,7 @@ public:
 bool
 pass_thread_jumps::gate (function *fun ATTRIBUTE_UNUSED)
 {
-  return (flag_expensive_optimizations
-	  && ! optimize_function_for_size_p (cfun));
+  return flag_expensive_optimizations;
 }