[PATCH] D62327: [X86][CodeGen][NFC] Delay `combineIncDecVector()` from DAGCombine to X86DAGToDAGISel

[Roman Lebedev via Phabricator via llvm-commits]

lebedev.ri created this revision.
lebedev.ri added reviewers: RKSimon, craig.topper.
lebedev.ri added a project: LLVM.

We were previously doing it in DAGCombine.
But we also want to do `sub %x, C` -> `add %x, (sub 0, C)` for vectors in DAGCombine.
So if we had `sub %x, -1`, we'll transform it to `add %x, 1`,
which `combineIncDecVector()` will immediately transform back into `sub %x, -1`,
and here we go again...

I've marked this as NFC since not a single test changes,
but since that 'changes' DAGCombine, probably this isn't fully NFC.


Repository:
  rL LLVM

https://reviews.llvm.org/D62327

Files:
  lib/Target/X86/X86ISelDAGToDAG.cpp
  lib/Target/X86/X86ISelLowering.cpp
  lib/Target/X86/X86ISelLowering.h

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