[backport from gcc-4.7/trunk <mikpe@it.uu.se>]

gcc/

2011-11-10  Richard Guenther  <rguenther@suse.de>

	PR tree-optimization/51070
	* tree-loop-distribution.c (generate_builtin): Do not replace
	the loop with a builtin if the partition contains statements which
	results are used outside of the loop.
	(pass_loop_distribution): Verify and collect.

gcc/testsuite/

2011-11-10  Richard Guenther  <rguenther@suse.de>

	PR tree-optimization/51070
	* gcc.dg/torture/pr51070.c: New testcase.

--- gcc-4.6.2/gcc/testsuite/gcc.dg/torture/pr51070.c.~1~	1970-01-01 01:00:00.000000000 +0100
+++ gcc-4.6.2/gcc/testsuite/gcc.dg/torture/pr51070.c	2011-11-19 14:57:56.000000000 +0100
@@ -0,0 +1,34 @@
+/* { dg-do compile } */
+
+int
+func_4 (int si1, int si2)
+{
+  return si1;
+}
+
+int
+func_14 (int left, int right)
+{
+  return 1;
+}
+
+int
+func_37 (int left, int right)
+{
+  return left;
+}
+
+int g_92[1024];
+int g_95[1024];
+int g_224;
+int g_352[1024];
+int
+func_9 ()
+{
+  for (; g_224; g_224 += 1)
+    {
+      g_95[0] = func_4 (func_37 (g_92[g_224], 0), 0);
+      g_92[g_224] = 0, g_352[g_224] = func_14 (0, 0);
+    }
+  return 0;
+}
--- gcc-4.6.2/gcc/tree-loop-distribution.c.~1~	2011-05-11 15:07:54.000000000 +0200
+++ gcc-4.6.2/gcc/tree-loop-distribution.c	2011-11-19 14:59:12.000000000 +0100
@@ -63,6 +63,48 @@ static bitmap remaining_stmts;
    predecessor a node that writes to memory.  */
 static bitmap upstream_mem_writes;
 
+/* Returns true when DEF is an SSA_NAME defined in LOOP and used after
+   the LOOP.  */
+
+static bool
+ssa_name_has_uses_outside_loop_p (tree def, loop_p loop)
+{
+  imm_use_iterator imm_iter;
+  use_operand_p use_p;
+
+  FOR_EACH_IMM_USE_FAST (use_p, imm_iter, def)
+    if (loop != loop_containing_stmt (USE_STMT (use_p)))
+      return true;
+
+  return false;
+}
+
+/* Returns true when STMT defines a scalar variable used after the
+   loop.  */
+
+static bool
+stmt_has_scalar_dependences_outside_loop (gimple stmt)
+{
+  tree name;
+
+  switch (gimple_code (stmt))
+    {
+    case GIMPLE_ASSIGN:
+      name = gimple_assign_lhs (stmt);
+      break;
+
+    case GIMPLE_PHI:
+      name = gimple_phi_result (stmt);
+      break;
+
+    default:
+      return false;
+    }
+
+  return TREE_CODE (name) == SSA_NAME
+    && ssa_name_has_uses_outside_loop_p (name, loop_containing_stmt (stmt));
+}
+
 /* Update the PHI nodes of NEW_LOOP.  NEW_LOOP is a duplicate of
    ORIG_LOOP.  */
 
@@ -332,10 +374,18 @@ generate_builtin (struct loop *loop, bit
 	{
 	  gimple stmt = gsi_stmt (bsi);
 
-	  if (gimple_code (stmt) != GIMPLE_LABEL
-	      && !is_gimple_debug (stmt)
-	      && bitmap_bit_p (partition, x++)
-	      && is_gimple_assign (stmt)
+	  if (gimple_code (stmt) == GIMPLE_LABEL
+	      || is_gimple_debug (stmt))
+	    continue;
+
+	  if (!bitmap_bit_p (partition, x++))
+	    continue;
+
+	  /* If the stmt has uses outside of the loop fail.  */
+	  if (stmt_has_scalar_dependences_outside_loop (stmt))
+	    goto end;
+
+	  if (is_gimple_assign (stmt)
 	      && !is_gimple_reg (gimple_assign_lhs (stmt)))
 	    {
 	      /* Don't generate the builtins when there are more than
@@ -826,48 +876,6 @@ fuse_partitions_with_similar_memory_acce
 	  }
 }
 
-/* Returns true when DEF is an SSA_NAME defined in LOOP and used after
-   the LOOP.  */
-
-static bool
-ssa_name_has_uses_outside_loop_p (tree def, loop_p loop)
-{
-  imm_use_iterator imm_iter;
-  use_operand_p use_p;
-
-  FOR_EACH_IMM_USE_FAST (use_p, imm_iter, def)
-    if (loop != loop_containing_stmt (USE_STMT (use_p)))
-      return true;
-
-  return false;
-}
-
-/* Returns true when STMT defines a scalar variable used after the
-   loop.  */
-
-static bool
-stmt_has_scalar_dependences_outside_loop (gimple stmt)
-{
-  tree name;
-
-  switch (gimple_code (stmt))
-    {
-    case GIMPLE_ASSIGN:
-      name = gimple_assign_lhs (stmt);
-      break;
-
-    case GIMPLE_PHI:
-      name = gimple_phi_result (stmt);
-      break;
-
-    default:
-      return false;
-    }
-
-  return TREE_CODE (name) == SSA_NAME
-    && ssa_name_has_uses_outside_loop_p (name, loop_containing_stmt (stmt));
-}
-
 /* Returns true when STMT will be code generated in a partition of RDG
    different than PART and that will not be code generated as a
    builtin.  */
@@ -1313,6 +1321,8 @@ struct gimple_opt_pass pass_loop_distrib
   0,				/* properties_provided */
   0,				/* properties_destroyed */
   0,				/* todo_flags_start */
-  TODO_dump_func                /* todo_flags_finish */
+  TODO_dump_func
+  | TODO_ggc_collect
+  | TODO_verify_ssa             /* todo_flags_finish */
  }
 };