I’ve been looking at compilation time issues in the LICM pass, and it looks to me like colorEHFunclets() is probably being called a lot more often than it needs to be for functions that have Windows EH personality functions. For one thing, the funclet coloring is happening when computeLoopSafetyInfo() is called from LoopIdiomRecognize and LoopUnswitch but those passes don’t use the coloring information. Beyond that, it’s called for every loop within LICM even though in many case the information won’t have changed since being computed for other loops in the same function.
I was thinking about pulling the funclet coloring out of computeLoopSafetyInfo() and moving it into an analysis pass that can be used by LICM. Does this sound reasonable?