* gimple-ssa-evrp-analyze.h (class evrp_range_analyzer): New data
	member USE_SCEV. 
	* gimple-ssa-evrp-analyze.c
	(evrp_range_analyzer::evrp_range_analyzer): Add new use_scev argument.
	Pass it to the vr_values ctor.
	(evrp_range_analyzer::record_ranges_from_phis): Conditionally use
	SCEV to refine ranges for PHIs.
	* gimple-ssa-evrp (evrp_dom_walker::evrp_dom_walker): Ask for
	SCEV analysis in the vr-values engine.
	* vr-values.h (class vr_values): New data meber USE_SCEV.
	* vr-values.c (vr_values::vr_values): Add new use_scev argument.
	(vr_values::extract_range_from_phi_node): Conditionally use
	SCEV to refine ranges for PHIs.
	

diff --git a/gcc/gimple-ssa-evrp-analyze.c b/gcc/gimple-ssa-evrp-analyze.c
index 68a2cdc..bc41be1 100644
--- a/gcc/gimple-ssa-evrp-analyze.c
+++ b/gcc/gimple-ssa-evrp-analyze.c
@@ -42,7 +42,8 @@ along with GCC; see the file COPYING3.  If not see
 #include "vr-values.h"
 #include "gimple-ssa-evrp-analyze.h"
 
-evrp_range_analyzer::evrp_range_analyzer () : stack (10)
+evrp_range_analyzer::evrp_range_analyzer (bool use_scev_)
+  : vr_values (use_scev_), stack (10), use_scev (use_scev_)
 {
   edge e;
   edge_iterator ei;
@@ -176,7 +177,8 @@ evrp_range_analyzer::record_ranges_from_phis (basic_block bb)
 	     to use VARYING for them.  But we can still resort to
 	     SCEV for loop header PHIs.  */
 	  struct loop *l;
-	  if (interesting
+	  if (use_scev
+	      && interesting
 	      && (l = loop_containing_stmt (phi))
 	      && l->header == gimple_bb (phi))
 	  vr_values.adjust_range_with_scev (&vr_result, l, phi, lhs);
@@ -341,3 +343,4 @@ evrp_range_analyzer::pop_value_range (tree var)
   stack.pop ();
   return vr;
 }
+
diff --git a/gcc/gimple-ssa-evrp-analyze.h b/gcc/gimple-ssa-evrp-analyze.h
index 3d64c50..18f5b8c 100644
--- a/gcc/gimple-ssa-evrp-analyze.h
+++ b/gcc/gimple-ssa-evrp-analyze.h
@@ -23,7 +23,7 @@ along with GCC; see the file COPYING3.  If not see
 class evrp_range_analyzer
 {
  public:
-  evrp_range_analyzer (void);
+  evrp_range_analyzer (bool);
   ~evrp_range_analyzer (void) { stack.release (); }
 
   void enter (basic_block);
@@ -65,6 +65,9 @@ class evrp_range_analyzer
 
   /* STACK holds the old VR.  */
   auto_vec<std::pair <tree, value_range*> > stack;
+
+  /* Whether or not to use SCEV to refine ranges.  */
+  bool use_scev;
 };
 
 #endif /* GCC_GIMPLE_SSA_EVRP_ANALYZE_H */
diff --git a/gcc/gimple-ssa-evrp.c b/gcc/gimple-ssa-evrp.c
index f56d67f..13e4e16 100644
--- a/gcc/gimple-ssa-evrp.c
+++ b/gcc/gimple-ssa-evrp.c
@@ -69,6 +69,7 @@ class evrp_dom_walker : public dom_walker
 public:
   evrp_dom_walker ()
     : dom_walker (CDI_DOMINATORS),
+      evrp_range_analyzer (true),
       evrp_folder (evrp_range_analyzer.get_vr_values ())
     {
       need_eh_cleanup = BITMAP_ALLOC (NULL);
diff --git a/gcc/tree-vrp.c b/gcc/tree-vrp.c
index 838822d..46be749 100644
--- a/gcc/tree-vrp.c
+++ b/gcc/tree-vrp.c
@@ -4737,6 +4737,7 @@ insert_range_assertions (void)
 class vrp_prop : public ssa_propagation_engine
 {
  public:
+  vrp_prop (bool use_scev_) : vr_values (use_scev_) { }
   enum ssa_prop_result visit_stmt (gimple *, edge *, tree *) FINAL OVERRIDE;
   enum ssa_prop_result visit_phi (gphi *) FINAL OVERRIDE;
 
@@ -6862,7 +6863,7 @@ execute_vrp (bool warn_array_bounds_p)
   /* For visiting PHI nodes we need EDGE_DFS_BACK computed.  */
   mark_dfs_back_edges ();
 
-  class vrp_prop vrp_prop;
+  class vrp_prop vrp_prop (true);
   vrp_prop.vrp_initialize ();
   vrp_prop.ssa_propagate ();
   vrp_prop.vrp_finalize (warn_array_bounds_p);
diff --git a/gcc/vr-values.c b/gcc/vr-values.c
index 2d11861..54b0be5 100644
--- a/gcc/vr-values.c
+++ b/gcc/vr-values.c
@@ -1907,7 +1907,8 @@ vr_values::dump_all_value_ranges (FILE *file)
 
 /* Initialize VRP lattice.  */
 
-vr_values::vr_values () : vrp_value_range_pool ("Tree VRP value ranges")
+vr_values::vr_values (bool use_scev_)
+  : vrp_value_range_pool ("Tree VRP value ranges"), use_scev (use_scev_)
 {
   values_propagated = false;
   num_vr_values = num_ssa_names;
@@ -2935,7 +2936,8 @@ scev_check:
      scev_check can be reached from two paths, one is a fall through from above
      "varying" label, the other is direct goto from code block which tries to
      avoid infinite simulation.  */
-  if ((l = loop_containing_stmt (phi))
+  if (use_scev
+      && (l = loop_containing_stmt (phi))
       && l->header == gimple_bb (phi))
     adjust_range_with_scev (vr_result, l, phi, lhs);
 
diff --git a/gcc/vr-values.h b/gcc/vr-values.h
index 124ee6f..bfeb1e4 100644
--- a/gcc/vr-values.h
+++ b/gcc/vr-values.h
@@ -37,7 +37,7 @@ along with GCC; see the file COPYING3.  If not see
 class vr_values
 {
  public:
-  vr_values (void);
+  vr_values (bool);
   ~vr_values (void);
 
   value_range *get_value_range (const_tree);
@@ -115,6 +115,9 @@ class vr_values
   /* Allocations for equivalences all come from this obstack.  */
   bitmap_obstack vrp_equiv_obstack;
 
+  /* Whether or not to use SCEV to refine ranges.  */
+  bool use_scev;
+
   /* Value range array.  After propagation, VR_VALUE[I] holds the range
      of values that SSA name N_I may take.  */
   unsigned int num_vr_values;