deadcode.dcf

来自「用Java实现的编译器。把源代码编译成SPARC汇编程序」· DCF 代码 · 共 40 行

class Program {
  
  int gl;
  int a1[10];

  int foo(int r) {
    return (2 * r);
  }

  int foo2(int r) {
    gl = 23;
    return (3 * r);
  }

  int foo3(int r) {
    // Note: this is *not* side-effect free, since it may generate 
    // a runtime failure
    return (a1[r]);
  }
  
  void main() {
    int a,b,c,d,e;

    callout("printf","A? ");
    a = callout("readint");

    d = a + foo(2);  // add and assign should be optimized away.
                     // call to foo may be optimized away.

    e = a + foo2(3); // should be optimized to just a call of foo2
    e = a1[a];       // should optimize out the arrayref, but 
		     // keep the error check

    e = foo3(2 * a); // should keep the call but eliminate the assignment
  }
}