[PATCH] D140638: [Codegen][LegalizeIntegerTypes] New legalization strategy for scalar shifts: shift through stack

[Eli Friedman via Phabricator via llvm-commits]

efriedma added a comment.

I won't insist on implementing everything in one patch.  I was going to say we need a bailout for targets that don't have unaligned loads... but looking at llvm/test/CodeGen/RISCV/shifts.ll, I guess the previous codegen is terrible enough that it's an improvement even if we expand unaligned loads to byte loads.  So I guess that's fine.



================
Comment at: llvm/lib/CodeGen/SelectionDAG/LegalizeIntegerTypes.cpp:4160
+  // And spill it into the stack slot.
+  Ch = DAG.getStore(Ch, dl, Init, StackPtr, MachinePointerInfo());
+
----------------
MachinePointerInfo::getUnknownStack instead of MachinePointerInfo()?  Or actually, DAGTypeLegalizer::SplitVecRes_INSERT_SUBVECTOR does the following:

```
  auto FrameIndex = cast<FrameIndexSDNode>(StackPtr.getNode())->getIndex();
  auto PtrInfo = MachinePointerInfo::getFixedStack(MF, FrameIndex);
```


Repository:
  rG LLVM Github Monorepo

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  https://reviews.llvm.org/D140638/new/

https://reviews.llvm.org/D140638