Some graphs (eg. v8-crypto) on the AWFY breakdown page (http://arewefastyet.com/?a=b&view=breakdown) have a gray background. I can only reproduce this with both TI and JM enabled (default prefs). I can reproduce with a tinderbox build of revision 53649a1d6e45 on OS X, but I remember seeing it before.
Did not get a reduction for this, but Jan downloaded the site and identified the place where we were breaking, and with spew output it was not hard to see the problem. Plain IFEQ and IFNE opcodes did not call fixDoubleTypes before branching, so integers were not being coerced to doubles when branching to a point in the script with associated phi nodes. http://hg.mozilla.org/projects/jaegermonkey/rev/9ff00d53b5a5