src/hotspot/cpu/ppc/vm_version_ppc.cpp

*** 127,136 ****
--- 127,147 ----
        warning("SuperwordUseVSX specified, but needs at least Power8.");
        FLAG_SET_DEFAULT(SuperwordUseVSX, false);
      }
    }
    MaxVectorSize = SuperwordUseVSX ? 16 : 8;
+ 
+   if (PowerArchitecturePPC64 >= 9) {
+     if (FLAG_IS_DEFAULT(UseCountTrailingZerosInstructionsPPC64)) {
+       FLAG_SET_ERGO(bool, UseCountTrailingZerosInstructionsPPC64, true);
+     }
+   } else {
+     if (UseCountTrailingZerosInstructionsPPC64) {
+       warning("UseCountTrailingZerosInstructionsPPC64 specified, but needs at least Power9.");
+       FLAG_SET_DEFAULT(UseCountTrailingZerosInstructionsPPC64, false);
+     }
+   }
  #endif
  
    // Create and print feature-string.
    char buf[(num_features+1) * 16]; // Max 16 chars per feature.
    jio_snprintf(buf, sizeof(buf),