test/mjsunit/compiler/compare-map-elim.js

// Copyright 2010 the V8 project authors. All rights reserved.
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// modification, are permitted provided that the following conditions are
// met:
//
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//       notice, this list of conditions and the following disclaimer.
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// Flags: --allow-natives-syntax --check-elimination

a = {
  f: function() { this.y = 3; }
};
b = {
  f: function() { this.y = 4; }
};

function x(z) {
  return z.f();
}

x(a);
x(b);
x(a);
x(b);
x(a);
x(b);

%OptimizeFunctionOnNextCall(x)

x(a);
x(b);