re PR tree-optimization/43934 (LIM should handle PHI nodes)

PR tree-optimization/43934
* tree-ssa-loop-im.c (determine_max_movement): Add PHI def constant cost.

From-SVN: r211302

gcc/ChangeLog

+2014-06-06  Christian Bruel  <christian.bruel@st.com>
+
+	PR tree-optimization/43934
+	* tree-ssa-loop-im.c (determine_max_movement): Add PHI def constant cost.
+
 2014-06-06  Richard Sandiford  <rdsandiford@googlemail.com>
 
 	* ira-lives.c (single_reg_class): Add missing break.  Explicitly

gcc/testsuite/ChangeLog

+2014-06-06  Christian Bruel  <christian.bruel@st.com>
+
+	PR tree-optimization/43934
+	* gcc.dg/tree-ssa/ssa-lim-8.c: New testcase.
+
 2014-06-05  S. Gilles  <sgilles@terpmail.umd.edu>
 
 	PR c/53119

gcc/testsuite/gcc.dg/tree-ssa/ssa-lim-8.c

+/* { dg-do compile } */
+/* { dg-options "-O -fdump-tree-lim1-details" } */
+
+void bar (int);
+void foo (int n, int m)
+{
+  unsigned i;
+  for (i = 0; i < n; ++i)
+    {
+      int x;
+      if (m < 0)
+	x = 1;
+      else
+	x = m;
+      bar (x);
+    }
+}
+
+/* { dg-final { scan-tree-dump-times "Moving PHI node" 1 "lim1"  } } */
+/* { dg-final { cleanup-tree-dump "lim1" } } */

gcc/tree-ssa-loop-im.c

@@ -719,8 +719,14 @@ determine_max_movement (gimple stmt, bool must_preserve_exec)
       FOR_EACH_PHI_ARG (use_p, stmt, iter, SSA_OP_USE)
 	{
 	  val = USE_FROM_PTR (use_p);
+
 	  if (TREE_CODE (val) != SSA_NAME)
-	    continue;
+	    {
+	      /* Assign const 1 to constants.  */
+	      min_cost = MIN (min_cost, 1);
+	      total_cost += 1;
+	      continue;
+	    }
 	  if (!add_dependency (val, lim_data, loop, false))
 	    return false;
 	  def_data = get_lim_data (SSA_NAME_DEF_STMT (val));