--- a/src/hotspot/share/opto/ifnode.cpp	Tue Apr 24 10:26:54 2018 -0700
+++ b/src/hotspot/share/opto/ifnode.cpp	Tue Apr 10 17:07:21 2018 +0200
@@ -775,6 +775,38 @@
   return success != NULL && fail != NULL;
 }
 
+bool IfNode::is_dominator_unc(CallStaticJavaNode* dom_unc, CallStaticJavaNode* unc) {
+  // Different methods and methods containing jsrs are not supported.
+  ciMethod* method = unc->jvms()->method();
+  ciMethod* dom_method = dom_unc->jvms()->method();
+  if (method != dom_method || method->has_jsrs()) {
+    return false;
+  }
+  // Check that both traps are in the same activation of the method (instead
+  // of two activations being inlined through different call sites) by verifying
+  // that the call stacks are equal for both JVMStates.
+  JVMState* dom_caller = dom_unc->jvms()->caller();
+  JVMState* caller = unc->jvms()->caller();
+  if ((dom_caller == NULL) != (caller == NULL)) {
+    // The current method must either be inlined into both dom_caller and
+    // caller or must not be inlined at all (top method). Bail out otherwise.
+    return false;
+  } else if (dom_caller != NULL && !dom_caller->same_calls_as(caller)) {
+    return false;
+  }
+  // Check that the bci of the dominating uncommon trap dominates the bci
+  // of the dominated uncommon trap. Otherwise we may not re-execute
+  // the dominated check after deoptimization from the merged uncommon trap.
+  ciTypeFlow* flow = dom_method->get_flow_analysis();
+  int bci = unc->jvms()->bci();
+  int dom_bci = dom_unc->jvms()->bci();
+  if (!flow->is_dominated_by(bci, dom_bci)) {
+    return false;
+  }
+
+  return true;
+}
+
 // Return projection that leads to an uncommon trap if any
 ProjNode* IfNode::uncommon_trap_proj(CallStaticJavaNode*& call) const {
   for (int i = 0; i < 2; i++) {
@@ -811,31 +843,7 @@
         return false;
       }
 
-      // Different methods and methods containing jsrs are not supported.
-      ciMethod* method = unc->jvms()->method();
-      ciMethod* dom_method = dom_unc->jvms()->method();
-      if (method != dom_method || method->has_jsrs()) {
-        return false;
-      }
-      // Check that both traps are in the same activation of the method (instead
-      // of two activations being inlined through different call sites) by verifying
-      // that the call stacks are equal for both JVMStates.
-      JVMState* dom_caller = dom_unc->jvms()->caller();
-      JVMState* caller = unc->jvms()->caller();
-      if ((dom_caller == NULL) != (caller == NULL)) {
-        // The current method must either be inlined into both dom_caller and
-        // caller or must not be inlined at all (top method). Bail out otherwise.
-        return false;
-      } else if (dom_caller != NULL && !dom_caller->same_calls_as(caller)) {
-        return false;
-      }
-      // Check that the bci of the dominating uncommon trap dominates the bci
-      // of the dominated uncommon trap. Otherwise we may not re-execute
-      // the dominated check after deoptimization from the merged uncommon trap.
-      ciTypeFlow* flow = dom_method->get_flow_analysis();
-      int bci = unc->jvms()->bci();
-      int dom_bci = dom_unc->jvms()->bci();
-      if (!flow->is_dominated_by(bci, dom_bci)) {
+      if (!is_dominator_unc(dom_unc, unc)) {
         return false;
       }
 
@@ -843,6 +851,8 @@
       // will be changed and the state of the dominating If will be
       // used. Checked that we didn't apply this transformation in a
       // previous compilation and it didn't cause too many traps
+      ciMethod* dom_method = dom_unc->jvms()->method();
+      int dom_bci = dom_unc->jvms()->bci();
       if (!igvn->C->too_many_traps(dom_method, dom_bci, Deoptimization::Reason_unstable_fused_if) &&
           !igvn->C->too_many_traps(dom_method, dom_bci, Deoptimization::Reason_range_check)) {
         success = unc_proj;
@@ -1220,6 +1230,10 @@
         return false;
       }
 
+      if (!is_dominator_unc(dom_unc, unc)) {
+        return false;
+      }
+
       return true;
     }
   }