src/share/vm/opto/loopTransform.cpp

@@ -1025,85 +1025,16 @@
     cmp = cmp->clone();
     register_new_node(cmp,main_end->in(CountedLoopEndNode::TestControl));
     _igvn.replace_input_of(bol, 1, cmp);
   }
 
-  //------------------------------
-  // Step A: Create Post-Loop.
-  Node* main_exit = main_end->proj_out(false);
-  assert( main_exit->Opcode() == Op_IfFalse, "" );
-  int dd_main_exit = dom_depth(main_exit);
-
-  // Step A1: Clone the loop body.  The clone becomes the post-loop.  The main
-  // loop pre-header illegally has 2 control users (old & new loops).
-  clone_loop( loop, old_new, dd_main_exit );
-  assert( old_new[main_end ->_idx]->Opcode() == Op_CountedLoopEnd, "" );
-  CountedLoopNode *post_head = old_new[main_head->_idx]->as_CountedLoop();
-  post_head->set_post_loop(main_head);
-
-  // Reduce the post-loop trip count.
-  CountedLoopEndNode* post_end = old_new[main_end ->_idx]->as_CountedLoopEnd();
-  post_end->_prob = PROB_FAIR;
-
-  // Build the main-loop normal exit.
-  IfFalseNode *new_main_exit = new IfFalseNode(main_end);
-  _igvn.register_new_node_with_optimizer( new_main_exit );
-  set_idom(new_main_exit, main_end, dd_main_exit );
-  set_loop(new_main_exit, loop->_parent);
-
-  // Step A2: Build a zero-trip guard for the post-loop.  After leaving the
-  // main-loop, the post-loop may not execute at all.  We 'opaque' the incr
-  // (the main-loop trip-counter exit value) because we will be changing
-  // the exit value (via unrolling) so we cannot constant-fold away the zero
-  // trip guard until all unrolling is done.
-  Node *zer_opaq = new Opaque1Node(C, incr);
-  Node *zer_cmp  = new CmpINode( zer_opaq, limit );
-  Node *zer_bol  = new BoolNode( zer_cmp, b_test );
-  register_new_node( zer_opaq, new_main_exit );
-  register_new_node( zer_cmp , new_main_exit );
-  register_new_node( zer_bol , new_main_exit );
-
-  // Build the IfNode
-  IfNode *zer_iff = new IfNode( new_main_exit, zer_bol, PROB_FAIR, COUNT_UNKNOWN );
-  _igvn.register_new_node_with_optimizer( zer_iff );
-  set_idom(zer_iff, new_main_exit, dd_main_exit);
-  set_loop(zer_iff, loop->_parent);
-
-  // Plug in the false-path, taken if we need to skip post-loop
-  _igvn.replace_input_of(main_exit, 0, zer_iff);
-  set_idom(main_exit, zer_iff, dd_main_exit);
-  set_idom(main_exit->unique_out(), zer_iff, dd_main_exit);
-  // Make the true-path, must enter the post loop
-  Node *zer_taken = new IfTrueNode( zer_iff );
-  _igvn.register_new_node_with_optimizer( zer_taken );
-  set_idom(zer_taken, zer_iff, dd_main_exit);
-  set_loop(zer_taken, loop->_parent);
-  // Plug in the true path
-  _igvn.hash_delete( post_head );
-  post_head->set_req(LoopNode::EntryControl, zer_taken);
-  set_idom(post_head, zer_taken, dd_main_exit);
-
-  Arena *a = Thread::current()->resource_area();
-  VectorSet visited(a);
-  Node_Stack clones(a, main_head->back_control()->outcnt());
-  // Step A3: Make the fall-in values to the post-loop come from the
-  // fall-out values of the main-loop.
-  for (DUIterator_Fast imax, i = main_head->fast_outs(imax); i < imax; i++) {
-    Node* main_phi = main_head->fast_out(i);
-    if( main_phi->is_Phi() && main_phi->in(0) == main_head && main_phi->outcnt() >0 ) {
-      Node *post_phi = old_new[main_phi->_idx];
-      Node *fallmain  = clone_up_backedge_goo(main_head->back_control(),
-                                              post_head->init_control(),
-                                              main_phi->in(LoopNode::LoopBackControl),
-                                              visited, clones);
-      _igvn.hash_delete(post_phi);
-      post_phi->set_req( LoopNode::EntryControl, fallmain );
-    }
-  }
+  // Add the post loop
+  PostLoopInfo post_loop_info;
+  insert_post_loop(loop, old_new, main_head, main_end, incr, limit, post_loop_info);
 
   // Update local caches for next stanza
-  main_exit = new_main_exit;
+  Node *main_exit = post_loop_info.new_main_exit;
 
 
   //------------------------------
   // Step B: Create Pre-Loop.
 

@@ -1156,12 +1087,13 @@
   // Plug in the true path
   _igvn.hash_delete( main_head );
   main_head->set_req(LoopNode::EntryControl, min_taken);
   set_idom(main_head, min_taken, dd_main_head);
 
-  visited.Clear();
-  clones.clear();
+  Arena *a = Thread::current()->resource_area();
+  VectorSet visited(a);
+  Node_Stack clones(a, main_head->back_control()->outcnt());
   // Step B3: Make the fall-in values to the main-loop come from the
   // fall-out values of the pre-loop.
   for (DUIterator_Fast i2max, i2 = main_head->fast_outs(i2max); i2 < i2max; i2++) {
     Node* main_phi = main_head->fast_out(i2);
     if( main_phi->is_Phi() && main_phi->in(0) == main_head && main_phi->outcnt() > 0 ) {

@@ -1183,16 +1115,12 @@
   // test that was guarding the loop nest. We add a special CastII on
   // the if branch that enters the loop, between the input induction
   // variable value and the induction variable Phi to preserve correct
   // dependencies.
 
-  // CastII for the post loop:
-  bool inserted = cast_incr_before_loop(zer_opaq->in(1), zer_taken, post_head);
-  assert(inserted, "no castII inserted");
-
   // CastII for the main loop:
-  inserted = cast_incr_before_loop(pre_incr, min_taken, main_head);
+  bool inserted = cast_incr_before_loop( pre_incr, min_taken, main_head );
   assert(inserted, "no castII inserted");
 
   // Step B4: Shorten the pre-loop to run only 1 iteration (for now).
   // RCE and alignment may change this later.
   Node *cmp_end = pre_end->cmp_node();

@@ -1250,11 +1178,11 @@
   main_head->set_trip_count(main_head->trip_count() - 1);
 
   // It's difficult to be precise about the trip-counts
   // for the pre/post loops.  They are usually very short,
   // so guess that 4 trips is a reasonable value.
-  post_head->set_profile_trip_cnt(4.0);
+  post_loop_info.post_head->set_profile_trip_cnt(4.0);
   pre_head->set_profile_trip_cnt(4.0);
 
   // Now force out all loop-invariant dominating tests.  The optimizer
   // finds some, but we _know_ they are all useless.
   peeled_dom_test_elim(loop,old_new);

@@ -1296,23 +1224,85 @@
   CountedLoopNode *main_head = loop->_head->as_CountedLoop();
   CountedLoopEndNode *main_end = main_head->loopexit();
   guarantee(main_end != NULL, "no loop exit node");
   // diagnostic to show loop end is not properly formed
   assert(main_end->outcnt() == 2, "1 true, 1 false path only");
-  uint dd_main_head = dom_depth(main_head);
-  uint max = main_head->outcnt();
 
   // mark this loop as processed
   main_head->mark_has_atomic_post_loop();
 
-  Node *pre_header = main_head->in(LoopNode::EntryControl);
-  Node *init = main_head->init_trip();
   Node *incr = main_end->incr();
   Node *limit = main_end->limit();
-  Node *stride = main_end->stride();
-  Node *cmp = main_end->cmp_node();
-  BoolTest::mask b_test = main_end->test_trip();
+
+  // In this case we throw away the result as we are not using it to connect anything else.
+  PostLoopInfo post_loop_info;
+  insert_post_loop(loop, old_new, main_head, main_end, incr, limit, post_loop_info);
+
+  // It's difficult to be precise about the trip-counts
+  // for post loops.  They are usually very short,
+  // so guess that unit vector trips is a reasonable value.
+  post_loop_info.post_head->set_profile_trip_cnt(cur_unroll);
+
+  // Now force out all loop-invariant dominating tests.  The optimizer
+  // finds some, but we _know_ they are all useless.
+  peeled_dom_test_elim(loop, old_new);
+  loop->record_for_igvn();
+}
+
+
+//-------------------------insert_scalar_rced_post_loop------------------------
+// Insert a copy of the rce'd main loop as a post loop,
+// We have not unrolled the main loop, so this is the right time to inject this.
+// Later we will examine the partner of this post loop pair which still has range checks
+// to see inject code which tests at runtime if the range checks are applicable.
+void PhaseIdealLoop::insert_scalar_rced_post_loop(IdealLoopTree *loop, Node_List &old_new) {
+  if (!loop->_head->is_CountedLoop()) return;
+
+  CountedLoopNode *cl = loop->_head->as_CountedLoop();
+
+  // only process RCE'd main loops
+  if (cl->has_range_checks() || !cl->is_main_loop()) return;
+
+#ifndef PRODUCT
+  if (TraceLoopOpts) {
+    tty->print("PostScalarRce  ");
+    loop->dump_head();
+  }
+#endif
+  C->set_major_progress();
+
+  // Find common pieces of the loop being guarded with pre & post loops
+  CountedLoopNode *main_head = loop->_head->as_CountedLoop();
+  CountedLoopEndNode *main_end = main_head->loopexit();
+  guarantee(main_end != NULL, "no loop exit node");
+  // diagnostic to show loop end is not properly formed
+  assert(main_end->outcnt() == 2, "1 true, 1 false path only");
+
+  Node *incr = main_end->incr();
+  Node *limit = main_end->limit();
+
+  // In this case we throw away the result as we are not using it to connect anything else.
+  PostLoopInfo post_loop_info;
+  insert_post_loop(loop, old_new, main_head, main_end, incr, limit, post_loop_info);
+
+  // It's difficult to be precise about the trip-counts
+  // for post loops.  They are usually very short,
+  // so guess that unit vector trips is a reasonable value.
+  post_loop_info.post_head->set_profile_trip_cnt(4.0);
+
+  // Now force out all loop-invariant dominating tests.  The optimizer
+  // finds some, but we _know_ they are all useless.
+  peeled_dom_test_elim(loop, old_new);
+  loop->record_for_igvn();
+}
+
+
+//------------------------------insert_post_loop-------------------------------
+// Insert post loops.  Add a post loop to the given loop passed.
+void PhaseIdealLoop::insert_post_loop(IdealLoopTree *loop, Node_List &old_new,
+                                      CountedLoopNode *main_head, CountedLoopEndNode *main_end,
+                                      Node *incr, Node *limit, PostLoopInfo &post_loop_info) {
 
   //------------------------------
   // Step A: Create a new post-Loop.
   Node* main_exit = main_end->proj_out(false);
   assert(main_exit->Opcode() == Op_IfFalse, "");

@@ -1323,10 +1313,11 @@
   clone_loop(loop, old_new, dd_main_exit);
   assert(old_new[main_end->_idx]->Opcode() == Op_CountedLoopEnd, "");
   CountedLoopNode *post_head = old_new[main_head->_idx]->as_CountedLoop();
   post_head->set_normal_loop();
   post_head->set_post_loop(main_head);
+  post_loop_info.post_head = post_head;
 
   // Reduce the post-loop trip count.
   CountedLoopEndNode* post_end = old_new[main_end->_idx]->as_CountedLoopEnd();
   post_end->_prob = PROB_FAIR;
 

@@ -1334,33 +1325,33 @@
   IfFalseNode *new_main_exit = new IfFalseNode(main_end);
   _igvn.register_new_node_with_optimizer(new_main_exit);
   set_idom(new_main_exit, main_end, dd_main_exit);
   set_loop(new_main_exit, loop->_parent);
 
-  // Step A2: Build a zero-trip guard for the vector post-loop.  After leaving the
-  // main-loop, the vector post-loop may not execute at all.  We 'opaque' the incr
-  // (the vectorized main-loop trip-counter exit value) because we will be changing
+  // Step A2: Build a zero-trip guard for the post-loop.  After leaving the
+  // main-loop, the post-loop may not execute at all.  We 'opaque' the incr
+  // (the previous loop trip-counter exit value) because we will be changing
   // the exit value (via additional unrolling) so we cannot constant-fold away the zero
   // trip guard until all unrolling is done.
   Node *zer_opaq = new Opaque1Node(C, incr);
   Node *zer_cmp = new CmpINode(zer_opaq, limit);
-  Node *zer_bol = new BoolNode(zer_cmp, b_test);
+  Node *zer_bol = new BoolNode(zer_cmp, main_end->test_trip());
   register_new_node(zer_opaq, new_main_exit);
   register_new_node(zer_cmp, new_main_exit);
   register_new_node(zer_bol, new_main_exit);
 
   // Build the IfNode
   IfNode *zer_iff = new IfNode(new_main_exit, zer_bol, PROB_FAIR, COUNT_UNKNOWN);
   _igvn.register_new_node_with_optimizer(zer_iff);
   set_idom(zer_iff, new_main_exit, dd_main_exit);
   set_loop(zer_iff, loop->_parent);
 
-  // Plug in the false-path, taken if we need to skip vector post-loop
+  // Plug in the false-path, taken if we need to skip this post-loop
   _igvn.replace_input_of(main_exit, 0, zer_iff);
   set_idom(main_exit, zer_iff, dd_main_exit);
   set_idom(main_exit->unique_out(), zer_iff, dd_main_exit);
-  // Make the true-path, must enter the vector post loop
+  // Make the true-path, must enter this post loop
   Node *zer_taken = new IfTrueNode(zer_iff);
   _igvn.register_new_node_with_optimizer(zer_taken);
   set_idom(zer_taken, zer_iff, dd_main_exit);
   set_loop(zer_taken, loop->_parent);
   // Plug in the true path

@@ -1369,11 +1360,11 @@
   set_idom(post_head, zer_taken, dd_main_exit);
 
   Arena *a = Thread::current()->resource_area();
   VectorSet visited(a);
   Node_Stack clones(a, main_head->back_control()->outcnt());
-  // Step A3: Make the fall-in values to the vector post-loop come from the
+  // Step A3: Make the fall-in values to the post-loop come from the
   // fall-out values of the main-loop.
   for (DUIterator_Fast imax, i = main_head->fast_outs(imax); i < imax; i++) {
     Node* main_phi = main_head->fast_out(i);
     if (main_phi->is_Phi() && main_phi->in(0) == main_head && main_phi->outcnt() >0) {
       Node *cur_phi = old_new[main_phi->_idx];

@@ -1388,19 +1379,11 @@
 
   // CastII for the new post loop:
   bool inserted = cast_incr_before_loop(zer_opaq->in(1), zer_taken, post_head);
   assert(inserted, "no castII inserted");
 
-  // It's difficult to be precise about the trip-counts
-  // for post loops.  They are usually very short,
-  // so guess that unit vector trips is a reasonable value.
-  post_head->set_profile_trip_cnt((float)slp_max_unroll_factor);
-
-  // Now force out all loop-invariant dominating tests.  The optimizer
-  // finds some, but we _know_ they are all useless.
-  peeled_dom_test_elim(loop, old_new);
-  loop->record_for_igvn();
+  post_loop_info.new_main_exit = new_main_exit;
 }
 
 //------------------------------is_invariant-----------------------------
 // Return true if n is invariant
 bool IdealLoopTree::is_invariant(Node* n) const {

@@ -2189,10 +2172,11 @@
     Node *iff = loop->_body[i];
     if (iff->Opcode() == Op_If ||
         iff->Opcode() == Op_RangeCheck) { // Test?
       // Test is an IfNode, has 2 projections.  If BOTH are in the loop
       // we need loop unswitching instead of iteration splitting.
+      old_new.push(iff);
       Node *exit = loop->is_loop_exit(iff);
       if( !exit ) continue;
       int flip = (exit->Opcode() == Op_IfTrue) ? 1 : 0;
 
       // Get boolean condition to test

@@ -2332,10 +2316,13 @@
           _igvn.replace_input_of(cd, 0, ctrl); // ctrl, not NULL
           --i;
           --imax;
         }
       }
+      if (limit->Opcode() == Op_LoadRange) {
+        old_new.pop();
+      }
 
     } // End of is IF
 
   }
 

@@ -2389,10 +2376,177 @@
   // The OpaqueNode is unshared by design
   assert( opqzm->outcnt() == 1, "cannot hack shared node" );
   _igvn.replace_input_of(opqzm, 1, main_limit);
 }
 
+//------------------------------has_range_checks-------------------------------
+// Check to see if RCE cleaned the current loop of range-checks.
+void PhaseIdealLoop::has_range_checks(IdealLoopTree *loop) {
+  assert(RangeCheckElimination, "");
+
+  // skip if not a counted loop
+  if (!loop->is_counted()) return;
+
+  CountedLoopNode *cl = loop->_head->as_CountedLoop();
+
+  // skip this loop if it is already marked
+  if (cl->has_range_checks()) return;
+
+  // Now check for existance of range checks
+  for (uint i = 0; i < loop->_body.size(); i++) {
+    Node *iff = loop->_body[i];
+    if (iff->Opcode() == Op_If ||
+      iff->Opcode() == Op_RangeCheck) {
+      cl->mark_has_range_checks();
+      break;
+    }
+  }
+}
+
+//-------------------------multi_version_post_loops----------------------------
+// Check the range checks that remain, if simple, use the bounds to guard
+// which version to a post loop we execute, one with range checks or one without
+bool PhaseIdealLoop::multi_version_post_loops(IdealLoopTree *rce_loop, IdealLoopTree *legacy_loop) {
+  bool multi_version_succeeded = false;
+  assert(RangeCheckElimination, "");
+  CountedLoopNode *legacy_cl = legacy_loop->_head->as_CountedLoop();
+  assert(legacy_cl->is_post_loop(), "");
+
+  // Check for existance of range checks using the unique instance to make a guard with
+  Unique_Node_List worklist;
+  for (uint i = 0; i < legacy_loop->_body.size(); i++) {
+    Node *iff = legacy_loop->_body[i];
+    if (iff->Opcode() == Op_If || iff->Opcode() == Op_RangeCheck) {
+      worklist.push(iff);
+    }
+  }
+
+  // Find RCE'd post loop so that we can stage its guard.
+  Node* ctrl = legacy_cl->in(LoopNode::EntryControl);
+  if (!ctrl->is_IfTrue() && !ctrl->is_IfFalse()) return multi_version_succeeded;
+  Node* iffm = ctrl->in(0);
+  if (!iffm->is_If()) return multi_version_succeeded;
+  Node* cur_bool = iffm->in(1);
+  if (!cur_bool->is_Bool()) return multi_version_succeeded;
+  Node* cur_cmp = cur_bool->in(1);
+  if (!cur_cmp->is_Cmp()) return multi_version_succeeded;
+  Node* cur_opq = cur_cmp->in(1);
+  // Can not optimize a loop if zero-trip Opaque1 node is optimized away.
+  if (cur_opq->Opcode() != Op_Opaque1) return multi_version_succeeded;
+
+  // Now we test that both the post loops are connected
+  Node* post_loop_region = iffm->in(0);
+  if (post_loop_region == NULL) return multi_version_succeeded;
+  if (!post_loop_region->is_Region()) return multi_version_succeeded;
+  Node* covering_region = post_loop_region->in(RegionNode::Control+1);
+  if (covering_region == NULL) return multi_version_succeeded;
+  if (!covering_region->is_Region()) return multi_version_succeeded;
+  Node* p_f = covering_region->in(RegionNode::Control);
+  if (p_f == NULL) return multi_version_succeeded;
+  if (!p_f->is_IfFalse()) return multi_version_succeeded;
+  if (!p_f->in(0)->is_CountedLoopEnd()) return multi_version_succeeded;
+  CountedLoopEndNode* rce_loop_end = p_f->in(0)->as_CountedLoopEnd();
+  if (rce_loop_end == NULL) return multi_version_succeeded;
+  CountedLoopNode* rce_cl = rce_loop_end->loopnode();
+  if (rce_cl == NULL || !rce_cl->is_post_loop()) return multi_version_succeeded;
+  CountedLoopNode *known_rce_cl = rce_loop->_head->as_CountedLoop();
+  if (rce_cl != known_rce_cl) return multi_version_succeeded;
+
+  // Then we fetch the cover entry test
+  ctrl = rce_cl->in(LoopNode::EntryControl);
+  if (!ctrl->is_IfTrue() && !ctrl->is_IfFalse()) return multi_version_succeeded;
+
+#ifndef PRODUCT
+  if (TraceLoopOpts) {
+    tty->print("PostMultiVersion\n");
+    rce_loop->dump_head();
+    legacy_loop->dump_head();
+  }
+#endif
+
+  // Now fetch the limit we want to compare against
+  Node *limit = rce_cl->limit();
+  bool first_time = true;
+
+  // If we got this far, we identified the post loop which has been RCE'd and
+  // we have a work list.  Now we will try to transform the if guard to cause
+  // the loop pair to be multi version executed with the determination left to runtime
+  // or the optimizer if full information is known about the given arrays at compile time.
+  Node *last_min = NULL;
+  multi_version_succeeded = true;
+  while (worklist.size()) {
+    Node* rc_iffm = worklist.pop();
+    if (rc_iffm->is_If()) {
+      Node *rc_bolzm = rc_iffm->in(1);
+      if (rc_bolzm->is_Bool()) {
+        Node *rc_cmpzm = rc_bolzm->in(1);
+        if (rc_cmpzm->is_Cmp()) {
+          Node *rc_left = rc_cmpzm->in(2);
+          if (rc_left->Opcode() != Op_LoadRange) {
+            multi_version_succeeded = false;
+            break;
+          }
+          if (first_time) {
+            last_min = rc_left;
+            first_time = false;
+          } else {
+            Node *cur_min = new MinINode(last_min, rc_left);
+            last_min = cur_min;
+            _igvn.register_new_node_with_optimizer(last_min);
+          }
+        }
+      }
+    }
+  }
+
+  // All we have to do is update the limit of the rce loop
+  // with the min of our expression and the current limit.
+  // We will use this expression to replace the current limit.
+  if (last_min && multi_version_succeeded) {
+    Node *cur_min = new MinINode(last_min, limit);
+    _igvn.register_new_node_with_optimizer(cur_min);
+    Node *cmp_node = rce_loop_end->cmp_node();
+    _igvn.replace_input_of(cmp_node, 2, cur_min);
+    set_idom(cmp_node, cur_min, dom_depth(ctrl));
+    set_ctrl(cur_min, ctrl);
+    set_loop(cur_min, rce_loop->_parent);
+
+    legacy_cl->mark_is_multiversioned();
+    rce_cl->mark_is_multiversioned();
+    multi_version_succeeded = true;
+
+    C->set_major_progress();
+  }
+
+  return multi_version_succeeded;
+}
+
+//-------------------------poison_rce_post_loop--------------------------------
+// Causes the rce'd post loop to be optimized away if multiverioning fails
+void PhaseIdealLoop::poison_rce_post_loop(IdealLoopTree *rce_loop) {
+  CountedLoopNode *rce_cl = rce_loop->_head->as_CountedLoop();
+  Node* ctrl = rce_cl->in(LoopNode::EntryControl);
+  if (ctrl->is_IfTrue() || ctrl->is_IfFalse()) {
+    Node* iffm = ctrl->in(0);
+    if (iffm->is_If()) {
+      Node* cur_bool = iffm->in(1);
+      if (cur_bool->is_Bool()) {
+        Node* cur_cmp = cur_bool->in(1);
+        if (cur_cmp->is_Cmp()) {
+          BoolTest::mask new_test = BoolTest::gt;
+          BoolNode *new_bool = new BoolNode(cur_cmp, new_test);
+          _igvn.replace_node(cur_bool, new_bool);
+          _igvn._worklist.push(new_bool);
+          Node* left_op = cur_cmp->in(1);
+          _igvn.replace_input_of(cur_cmp, 2, left_op);
+          C->set_major_progress();
+        }
+      }
+    }
+  }
+}
+
 //------------------------------DCE_loop_body----------------------------------
 // Remove simplistic dead code from loop body
 void IdealLoopTree::DCE_loop_body() {
   for( uint i = 0; i < _body.size(); i++ )
     if( _body.at(i)->outcnt() == 0 )

@@ -2746,12 +2900,24 @@
       phase->insert_pre_post_loops(this,old_new, !may_rce_align);
 
     // Adjust the pre- and main-loop limits to let the pre and post loops run
     // with full checks, but the main-loop with no checks.  Remove said
     // checks from the main body.
-    if (should_rce)
-      phase->do_range_check(this,old_new);
+    if (should_rce) {
+      old_new.clear();
+      phase->do_range_check(this, old_new);
+      if (old_new.size() > 0) {
+        cl->mark_has_range_checks();
+        old_new.clear();
+      }
+    }
+
+    if (should_rce && should_unroll && !should_peel && PostLoopMultiversioning) {
+      // Try to setup multiversioning on main loops before they are unrolled
+      if (cl->is_main_loop() && (cl->unrolled_count() == 1))
+        phase->insert_scalar_rced_post_loop(this, old_new);
+    }
 
     // Double loop body for unrolling.  Adjust the minimum-trip test (will do
     // twice as many iterations as before) and the main body limit (only do
     // an even number of trips).  If we are peeling, we might enable some RCE
     // and we'd rather unroll the post-RCE'd loop SO... do not unroll if