[PATCH] D151823: [RISCV] Combine vmv.s.x (vslideup pt, v, 1, <all-ones>, vl), scalar, vl to vslide1up

[Luke Lau via Phabricator via llvm-commits]

luke added inline comments.


================
Comment at: llvm/lib/Target/RISCV/RISCVISelLowering.cpp:12480
+        VL != Slide->getOperand(4) || !isNonZeroAVL(VL))
+      return SDValue();
+
----------------
It's not documented in `RISCVISelLowering.h` but I believe `RISCVISD::VSLIDEUP_VL` takes a policy operand (for both the mask and tail). It doesn't look like `RISCVISD::VSLIDE1UP_VL` has it though, so I'm not sure what policy it uses.

Either way do we need to check the vslideup's policy here?


================
Comment at: llvm/lib/Target/RISCV/RISCVISelLowering.cpp:12482
+
+    if (Slide->getValueType(0).getVectorElementType().getSizeInBits() !=
+        VT.getVectorElementType().getSizeInBits())
----------------
Nit, could possibly use `Slide.getScalarValueSizeInBits() != VT.getScalarSizeInBits()`


Repository:
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  https://reviews.llvm.org/D151823/new/

https://reviews.llvm.org/D151823