* gimple.h (stmt_can_terminate_bb_p): New function.

	* tree-cfg.c (need_fake_edge_p): Rename to ...
	(stmt_can_terminate_bb_p): ... this; return true if stmt can
	throw external; handle const and pure calls.
	* tree-ssa-loop-niter.c (loop_only_exit_p): Use it.


git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@238336 138bc75d-0d04-0410-961f-82ee72b054a4

4 files changed, 29 insertions, 18 deletions

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index 24b929812b6..5830663300f 100644
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,11 @@
+2016-07-14  Jan Hubicka  <hubicka@ucw.cz>
+
+	* gimple.h (stmt_can_terminate_bb_p): New function.
+	* tree-cfg.c (need_fake_edge_p): Rename to ...
+	(stmt_can_terminate_bb_p): ... this; return true if stmt can
+	throw external; handle const and pure calls.
+	* tree-ssa-loop-niter.c (loop_only_exit_p): Use it.
+
 2016-07-14  Richard Biener  <rguenther@suse.de>
 
 	PR tree-optimization/71866
diff --git a/gcc/gimple.h b/gcc/gimple.h
index 1da719c52e0..980bdf8314c 100644
--- a/gcc/gimple.h
+++ b/gcc/gimple.h
@@ -1526,6 +1526,7 @@ extern void gimple_seq_set_location (gimple_seq, location_t);
 extern void gimple_seq_discard (gimple_seq);
 extern void maybe_remove_unused_call_args (struct function *, gimple *);
 extern bool gimple_inexpensive_call_p (gcall *);
+extern bool stmt_can_terminate_bb_p (gimple *);
 
 /* Formal (expression) temporary table handling: multiple occurrences of
    the same scalar expression are evaluated into the same temporary.  */
diff --git a/gcc/tree-cfg.c b/gcc/tree-cfg.c
index 6d6943503fe..07280202ba3 100644
--- a/gcc/tree-cfg.c
+++ b/gcc/tree-cfg.c
@@ -7919,15 +7919,20 @@ gimple_block_ends_with_condjump_p (const_basic_block bb)
 }
 
 
-/* Return true if we need to add fake edge to exit at statement T.
-   Helper function for gimple_flow_call_edges_add.  */
+/* Return true if statement T may terminate execution of BB in ways not
+   explicitly represtented in the CFG.  */
 
-static bool
-need_fake_edge_p (gimple *t)
+bool
+stmt_can_terminate_bb_p (gimple *t)
 {
   tree fndecl = NULL_TREE;
   int call_flags = 0;
 
+  /* Eh exception not handled internally terminates execution of the whole
+     function.  */
+  if (stmt_can_throw_external (t))
+    return true;
+
   /* NORETURN and LONGJMP calls already have an edge to exit.
      CONST and PURE calls do not need one.
      We don't currently check for CONST and PURE here, although
@@ -7960,6 +7965,13 @@ need_fake_edge_p (gimple *t)
       edge e;
       basic_block bb;
 
+      if (call_flags & (ECF_PURE | ECF_CONST)
+	  && !(call_flags & ECF_LOOPING_CONST_OR_PURE))
+	return false;
+
+      /* Function call may do longjmp, terminate program or do other things.
+	 Special case noreturn that have non-abnormal edges out as in this case
+	 the fact is sufficiently represented by lack of edges out of T.  */
       if (!(call_flags & ECF_NORETURN))
 	return true;
 
@@ -8024,7 +8036,7 @@ gimple_flow_call_edges_add (sbitmap blocks)
       if (!gsi_end_p (gsi))
 	t = gsi_stmt (gsi);
 
-      if (t && need_fake_edge_p (t))
+      if (t && stmt_can_terminate_bb_p (t))
 	{
 	  edge e;
 
@@ -8059,7 +8071,7 @@ gimple_flow_call_edges_add (sbitmap blocks)
 	  do
 	    {
 	      stmt = gsi_stmt (gsi);
-	      if (need_fake_edge_p (stmt))
+	      if (stmt_can_terminate_bb_p (stmt))
 		{
 		  edge e;
 
diff --git a/gcc/tree-ssa-loop-niter.c b/gcc/tree-ssa-loop-niter.c
index 732e06a3553..182753cef3d 100644
--- a/gcc/tree-ssa-loop-niter.c
+++ b/gcc/tree-ssa-loop-niter.c
@@ -2159,7 +2159,6 @@ loop_only_exit_p (const struct loop *loop, const_edge exit)
   basic_block *body;
   gimple_stmt_iterator bsi;
   unsigned i;
-  gimple *call;
 
   if (exit != single_exit (loop))
     return false;
@@ -2168,17 +2167,8 @@ loop_only_exit_p (const struct loop *loop, const_edge exit)
   for (i = 0; i < loop->num_nodes; i++)
     {
       for (bsi = gsi_start_bb (body[i]); !gsi_end_p (bsi); gsi_next (&bsi))
-	{
-	  call = gsi_stmt (bsi);
-	  if (gimple_code (call) != GIMPLE_CALL)
-	    continue;
-
-	  if (gimple_has_side_effects (call))
-	    {
-	      free (body);
-	      return false;
-	    }
-	}
+	if (stmt_can_terminate_bb_p (gsi_stmt (bsi)))
+	  return true;
     }
 
   free (body);