ADDITIONAL SYSTEM INFORMATION :
Windows 10, openjdk-14-ea+30_windows-x64

A DESCRIPTION OF THE PROBLEM :
Source code:

void m(Object obj) {
    if (obj instanceof String s) {
        s.hashCode();
    }
}

Emitted code:

  void m(java.lang.Object);
    Code:
       0: aload_1
       1: astore_3
       2: aload_3
       3: instanceof #7 // class java/lang/String
       6: ifeq 27
       9: aload_3
      10: checkcast #7 // class java/lang/String
      13: dup
      14: astore_2
      15: aload_3
      16: checkcast #7 // class java/lang/String
      19: if_acmpne 27
      22: aload_2
      23: invokevirtual #9 // Method java/lang/String.hashCode:()I
      26: pop
      27: return

For me it looks like instructions 9-19 produce code:

if ((String)obj == (String)obj) {...}

which seems pointless.


FREQUENCY : always