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723bdb5e3f
This is a follow-up to the activity in the bug at http://llvm.org/bugs/show_bug.cgi?id=18663 . The underlying issue has to do with how the KILL pseudo-instruction is handled. I defer to Hal/Jakob/Uli for additional details and background. This will disable the (bad?) assert, add an associated fixme comment, and add a pair of tests. The code change and the pr18663-2.ll test are copied from the referenced bug. That test does not immediately fail in my environment, but I have added the pr18663.ll test which does. (Comment from Hal) to provide everyone else with some context, this assert was not bad when it was written. At that time, we only generated KILL pseudo instructions around subregister copies. This logic, unfortunately, had its own problems. In r199797, the relevant logic in MachineCopyPropagation was replaced to generate KILLs for other kinds of copies too. This change in semantics broke this now-problematic assumption in AggressiveAntiDepBreaker. The AggressiveAntiDepBreaker really needs a proper cleanup to deal with the change, but removing the assert (which just allows the function to return false) is a safe conservative behavior, and should do for the time being. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@214429 91177308-0d34-0410-b5e6-96231b3b80d8