freedreno/ir3: avoid fan-in sources referring to same instruction
freedreno/ir3: avoid fan-in sources referring to same instruction

Since the RA has to be done s.t. each one gets its own (adjacent)
register, it would complicate matters if instructions were allowed to be
repeated. This enables copy-propagation use in situations where
previously that might have happened.

Signed-off-by: Ilia Mirkin <bcbbb7aa705ec3a5fc5824c01a845186c3d62fca@alum.mit.edu>
Signed-off-by: Rob Clark <6f78cdb10adbe0a7fbbf4098125a51f401c77a5f@freedesktop.org>

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