src/share/vm/opto/stringopts.cpp

*** 820,834 ****
                iff = ctrl->in(1)->in(0)->as_If();
                ctrl = iff->in(0);
              }
            } else if (ctrl->is_IfTrue()) { // null checks, class checks
              iff = ctrl->in(0)->as_If();
-             assert(iff->is_If(), "must be if");
              // Verify that the other arm is an uncommon trap
              Node* otherproj = iff->proj_out(1 - ctrl->as_Proj()->_con);
              CallStaticJavaNode* call = otherproj->unique_out()->isa_CallStaticJava();
!             assert(strcmp(call->_name, "uncommon_trap") == 0, "must be uncommond trap");
              ctrl = iff->in(0);
            } else {
              break;
            }
          }
--- 820,833 ----
                iff = ctrl->in(1)->in(0)->as_If();
                ctrl = iff->in(0);
              }
            } else if (ctrl->is_IfTrue()) { // null checks, class checks
              iff = ctrl->in(0)->as_If();
              // Verify that the other arm is an uncommon trap
              Node* otherproj = iff->proj_out(1 - ctrl->as_Proj()->_con);
              CallStaticJavaNode* call = otherproj->unique_out()->isa_CallStaticJava();
!             assert(strcmp(call->_name, "uncommon_trap") == 0, "must be uncommon trap");
              ctrl = iff->in(0);
            } else {
              break;
            }
          }
*** 912,921 ****
--- 911,927 ----
      } else if (ptr->is_IfTrue()) {
        IfNode* iff = ptr->in(0)->as_If();
        BoolNode* b = iff->in(1)->isa_Bool();
  
        if (b == NULL) {
+ #ifndef PRODUCT
+         if (PrintOptimizeStringConcat) {
+           tty->print_cr("unexpected input to IfNode");
+           iff->in(1)->dump();
+           tty->cr();
+         }
+ #endif
          fail = true;
          break;
        }
  
        Node* cmp = b->in(1);