[PATCH] D66936: [DFAPacketizer] Track resources for packetized instructions

[James Molloy via Phabricator via llvm-commits]

jmolloy created this revision.
jmolloy added reviewers: ThomasRaoux, kparzysz.
Herald added subscribers: llvm-commits, jsji.
Herald added a project: LLVM.

This patch allows the DFAPacketizer to be queried after a packet is formed to work out which
resources were allocated to the packetized instructions.

This is particularly important for targets that do their own bundle packing - it's not
sufficient to know simply that instructions can share a packet; which slots are used is
also required for encoding.

This extends the emitter to emit a side-table containing resource usage diffs for each
state transition. The packetizer maintains a set of all possible resource states in its
current state. After packetization is complete, all remaining resource states are
possible packetization strategies.

The sidetable is only ~500K for Hexagon, but the extra tracking is disabled by default
(most uses of the packetizer like MachinePipeliner don't care and don't need the extra
maintained state).


Repository:
  rL LLVM

https://reviews.llvm.org/D66936

Files:
  include/llvm/CodeGen/DFAPacketizer.h
  lib/CodeGen/DFAPacketizer.cpp
  lib/Target/Hexagon/HexagonVLIWPacketizer.cpp
  test/CodeGen/Hexagon/packetizer-resources.ll
  utils/TableGen/DFAPacketizerEmitter.cpp

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