Conversation

@zwarich @resistor @chandlerc So I suspect one reason is because GCC has both global ranges and on demand ranges. most of the time global ranges are enough for most passes to use. And then for the on demand ones, it is uses the global ones as a starting point rather than recomputing those too. Plus there is a cache while doing on demand ones since it is just as likely you ask for one SSA name in one BB as you could another SSA name.