Performance improvement for Math.max and Math.min...

src/math.js

 // Copyright 2006-2008 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 110 matching lines @@
   if (length == 0) {
     return -1/0;  // Compiler constant-folds this to -Infinity.
   }
   var r = arg1;
   if (!IS_NUMBER(r)) r = ToNumber(r);
   if (NUMBER_IS_NAN(r)) return r;
   for (var i = 1; i < length; i++) {
     var n = %_Arguments(i);
     if (!IS_NUMBER(n)) n = ToNumber(n);
     if (NUMBER_IS_NAN(n)) return n;
-    // Make sure +0 is considered greater than -0.
-    if (n > r || (r === 0 && n === 0 && !%_IsSmi(r))) r = n;
+    // Make sure +0 is considered greater than -0.  -0 is never a Smi, +0 can be
+    // a Smi or heap number.
+    if (n > r || (r === 0 && n === 0 && !%_IsSmi(r) && 1 / r < 0)) r = n;
   }
   return r;
 }
 
 // ECMA 262 - 15.8.2.12
 function MathMin(arg1, arg2) {  // length == 2
   var length = %_ArgumentsLength();
   if (length == 0) {
     return 1/0;  // Compiler constant-folds this to Infinity.
   }
   var r = arg1;
   if (!IS_NUMBER(r)) r = ToNumber(r);
   if (NUMBER_IS_NAN(r)) return r;
   for (var i = 1; i < length; i++) {
     var n = %_Arguments(i);
     if (!IS_NUMBER(n)) n = ToNumber(n);
     if (NUMBER_IS_NAN(n)) return n;
-    // Make sure -0 is considered less than +0.
-    if (n < r || (r === 0 && n === 0 && !%_IsSmi(n))) r = n;
+    // Make sure -0 is considered less than +0.  -0 is never a Smi, +0 can b a
+    // Smi or a heap number.
+    if (n < r || (r === 0 && n === 0 && !%_IsSmi(n) && 1 / n < 0)) r = n;
   }
   return r;
 }
 
 // ECMA 262 - 15.8.2.13
 function MathPow(x, y) {
   if (!IS_NUMBER(x)) x = ToNumber(x);
   if (!IS_NUMBER(y)) y = ToNumber(y);
   return %Math_pow(x, y);
 }
@@ skipping 90 matching lines @@
     "tan", MathTan,
     "atan2", MathAtan2,
     "pow", MathPow,
     "max", MathMax,
     "min", MathMin
   ));
 };
 
 
 SetupMath();