[PATCH] D96015: [RegAllocFast] Handle case where operand of copy cannot be assigned.

[Quentin Colombet via Phabricator via llvm-commits]

qcolombet added a comment.

Is it something we could fix in the scheduler instead?

I think it is fair to end up with a "run out of registers" error here. Without changing the schedule, the allocation is not possible.

The expectation is the scheduler is supposed to keep the physical registers live-ranges as small as possible.

Basically, I am mildly against having the fast allocator doing some sort of rescheduling. This opens the door of all of crazy thing :). (Like you realized, copy are not special here, the same problem could happen with any instruction.)


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https://reviews.llvm.org/D96015