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I'm running into a problem with subregs during trivial coalescing in the linear scan allocator. Should RALinScan::attemptTrivialCoalescing be allowed to coalesce a COPY that uses a subreg as a destination? I've got the following sequence of code (unfortunately for an out of tree target) that is moving 32 and 64 bit sub-registers around within a 128 bit register. By the time the register