Mozilla plan to fold mozjs and gkmedias back to xul on Windows

After moving to VC2013, in the end Mozilla will make the decision, of course, we expect the merging can produce better optimization.

The bugzilla link is and

But according to tete009’s origin compare results, the merging may be not good for some benchmark result:

Benchmark origin fold mozjs into xul fold gkmedias into xul
Sunspider 178.5ms 182.7ms 178.6ms
Kraken 1420.2ms 1451.8ms 1421.7ms
Google RoboHornet 123.70 118.73 119.39
sinz Maze 564.45 607.93 597.84

The result is not good for some benchmark especially for Javascript Benchmark, only is improved in sinz Maze test.

So whether we should revert the changes is worth discussing. But the folding certainly improve the compiler’s inline and PGO optimazation a lot, we don’t know where the performance regression comes from.