[PATCH] D36619: [MachineCombiner] Update instruction depths incrementally for large BBs.

[Florian Hahn via Phabricator via llvm-commits]

fhahn added inline comments.


================
Comment at: lib/CodeGen/MachineCombiner.cpp:396
+  if (IncrementalUpdate)
+    for (auto *InstrPtr : InsInstrs)
+      MinInstr->updateDepth(MBB, *InstrPtr, RegUnits);
----------------
Gerolf wrote:
> You could call updateDepths here as well. Also if you had code like if (IncrementalUpdate) MinInstr->updateDepths(...) else MinInstr->invalidate(MBB) you could spare two parameters (at the cost of adding such a line after each call). It feels more natural to me than packing the code inside the insertDelete...() procedure.
This is slightly more difficult, I think, as MachineBasicBlock::iterator iterates over instruction references while InsInstrs contains instruction pointers. I'll leave it as it is for now and will think a bit more if we can make this nicer.

I think it is slightly safer to update the state of the trace here, as this should always be done if we modify the basic block.


https://reviews.llvm.org/D36619