From 65f8bbbcc74a4777f0629190ea9121fc94a79257 Mon Sep 17 00:00:00 2001
From: Sebastian Pop <s.pop@samsung.com>
Date: Fri, 28 Aug 2015 15:51:12 -0500
Subject: backport fix for PR65735

	PR tree-optimization/65735
	* tree-ssa-threadedge.c (fsm_find_control_statement_thread_paths):
	Remove visited_phis argument, add visited_bbs, avoid recursing into the
	same bb rather than just into the same phi node.
	(thread_through_normal_block): Adjust caller.

	* gcc.c-torture/compile/pr65735.c: New test.
---
 .../gcc/testsuite/gcc.c-torture/compile/pr65735.c   | 21 +++++++++++++++++++++
 gcc-4.9/gcc/tree-ssa-threadedge.c                   | 12 ++++++------
 2 files changed, 27 insertions(+), 6 deletions(-)
 create mode 100644 gcc-4.9/gcc/testsuite/gcc.c-torture/compile/pr65735.c

(limited to 'gcc-4.9/gcc')

diff --git a/gcc-4.9/gcc/testsuite/gcc.c-torture/compile/pr65735.c b/gcc-4.9/gcc/testsuite/gcc.c-torture/compile/pr65735.c
new file mode 100644
index 000000000..c30de8ea3
--- /dev/null
+++ b/gcc-4.9/gcc/testsuite/gcc.c-torture/compile/pr65735.c
@@ -0,0 +1,21 @@
+/* PR tree-optimization/65735 */
+
+int foo (void);
+
+void
+bar (int a, int b, int c)
+{
+  while (!a)
+    {
+      c = foo ();
+      if (c == 7)
+	c = b;
+      switch (c)
+	{
+	case 1:
+	  a = b++;
+	  if (b)
+	    b = 1;
+	}
+    }
+}
diff --git a/gcc-4.9/gcc/tree-ssa-threadedge.c b/gcc-4.9/gcc/tree-ssa-threadedge.c
index cad91ef66..604123e10 100644
--- a/gcc-4.9/gcc/tree-ssa-threadedge.c
+++ b/gcc-4.9/gcc/tree-ssa-threadedge.c
@@ -947,7 +947,7 @@ static int max_threaded_paths;
 
 static void
 fsm_find_control_statement_thread_paths (tree expr,
-					 pointer_set_t *visited_phis,
+					 pointer_set_t *visited_bbs,
 					 vec<basic_block, va_gc> *&path,
 					 bool seen_loop_phi)
 {
@@ -966,7 +966,7 @@ fsm_find_control_statement_thread_paths (tree expr,
     return;
 
   /* Avoid infinite recursion.  */
-  if (pointer_set_insert (visited_phis, def_stmt))
+  if (pointer_set_insert (visited_bbs, var_bb))
     return;
 
   int next_path_length = 0;
@@ -1040,7 +1040,7 @@ fsm_find_control_statement_thread_paths (tree expr,
 	{
 	  vec_safe_push (path, bbi);
 	  /* Recursively follow SSA_NAMEs looking for a constant definition.  */
-	  fsm_find_control_statement_thread_paths (arg, visited_phis, path,
+	  fsm_find_control_statement_thread_paths (arg, visited_bbs, path,
 						   seen_loop_phi);
 
 	  path->pop ();
@@ -1306,13 +1306,13 @@ thread_through_normal_block (edge e,
       vec<basic_block, va_gc> *bb_path;
       vec_alloc (bb_path, n_basic_blocks_for_fn (cfun));
       vec_safe_push (bb_path, e->dest);
-      pointer_set_t *visited_phis = pointer_set_create ();
+      pointer_set_t *visited_bbs = pointer_set_create ();
 
       max_threaded_paths = PARAM_VALUE (PARAM_MAX_FSM_THREAD_PATHS);
-      fsm_find_control_statement_thread_paths (cond, visited_phis, bb_path,
+      fsm_find_control_statement_thread_paths (cond, visited_bbs, bb_path,
 					       false);
 
-      pointer_set_destroy (visited_phis);
+      pointer_set_destroy (visited_bbs);
       vec_free (bb_path);
     }
   return 0;
-- 
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