8269746: C2: assert(!in->is_CFG()) failed: CFG Node with no controlli…

…ng input?

Backport-of: 8f798b8

src/hotspot/share/opto/callnode.cpp

@@ -1156,8 +1156,14 @@ Node *SafePointNode::Ideal(PhaseGVN *phase, bool can_reshape) {
 Node* SafePointNode::Identity(PhaseGVN* phase) {
 
   // If you have back to back safepoints, remove one
-  if( in(TypeFunc::Control)->is_SafePoint() )
-    return in(TypeFunc::Control);
+  if (in(TypeFunc::Control)->is_SafePoint()) {
+    Node* out_c = unique_ctrl_out();
+    // This can be the safepoint of an outer strip mined loop if the inner loop's backedge was removed. Replacing the
+    // outer loop's safepoint could confuse removal of the outer loop.
+    if (out_c != NULL && !out_c->is_OuterStripMinedLoopEnd()) {
+      return in(TypeFunc::Control);
+    }
+  }
 
   if( in(0)->is_Proj() ) {
     Node *n0 = in(0)->in(0);