Hello, I'm developping a math application compiled from c++ to javscript with emscripten 1.34.1 http://www-fourier.ujf-grenoble.fr/~parisse/xcasen.html (source http://www-fourier.ujf-grenoble.fr/~parisse/giac/emgiac.tgz) Under Firefox 45, performances are good, for example on my Mac, factoring a 128 bit integer takes 1/10 of second http://www-fourier.ujf-grenoble.fr/%7eparisse/xcasen.html#+time(ifactor(2**128+1))& But with newer Firefox releases, the speed as decreased, by a factor of 10 with Firefox 48, now it takes one second for the same computation. The Firefox desktop version is now significantly slower than the native version and the mobile version becomes really too slow. Is there some explanation and workaround other than telling my users to downgrade to Firefox 45? Thanks.