commit 72f4e656b8feb3665bd074fadf1db1e72b385030
author Philip Reames <preames@rivosinc.com> Thu Feb 13 11:06:34 2025 -0800
committer Philip Reames <listmail@philipreames.com> Thu Feb 13 11:17:54 2025 -0800
tree 3cdcb32fec70781e94284f76da27f5dd93b8823c
parent 4ac79a8c988ff74984b78c13d489eafcce9189e5

[RISCV] Revise interface of isLegalBitRotate [nfc]

Remove a dead parameter (DAG), and replace the ShuffleVectorSDNode param
with the two things we need from the shuffle (mask and VT).  There's
further room to improve this code, but this gets me what I need for an
upcoming patch.

llvm/lib/Target/RISCV/RISCVISelLowering.cpp

diff --git a/llvm/lib/Target/RISCV/RISCVISelLowering.cpp b/llvm/lib/Target/RISCV/RISCVISelLowering.cpp
index 829eef2..da04880 100644
--- a/llvm/lib/Target/RISCV/RISCVISelLowering.cpp
+++ b/llvm/lib/Target/RISCV/RISCVISelLowering.cpp
@@ -5072,21 +5072,17 @@
   return Res;
 }
 
-static bool isLegalBitRotate(ShuffleVectorSDNode *SVN,
-                             SelectionDAG &DAG,
+static bool isLegalBitRotate(ArrayRef<int> Mask, EVT VT,
                              const RISCVSubtarget &Subtarget,
                              MVT &RotateVT, unsigned &RotateAmt) {
-  SDLoc DL(SVN);
-
-  EVT VT = SVN->getValueType(0);
   unsigned NumElts = VT.getVectorNumElements();
   unsigned EltSizeInBits = VT.getScalarSizeInBits();
   unsigned NumSubElts;
-  if (!ShuffleVectorInst::isBitRotateMask(SVN->getMask(), EltSizeInBits, 2,
+  if (!ShuffleVectorInst::isBitRotateMask(Mask, EltSizeInBits, 2,
                                           NumElts, NumSubElts, RotateAmt))
     return false;
   RotateVT = MVT::getVectorVT(MVT::getIntegerVT(EltSizeInBits * NumSubElts),
-                                  NumElts / NumSubElts);
+                              NumElts / NumSubElts);
 
   // We might have a RotateVT that isn't legal, e.g. v4i64 on zve32x.
   return Subtarget.getTargetLowering()->isTypeLegal(RotateVT);
@@ -5103,7 +5099,7 @@
   EVT VT = SVN->getValueType(0);
   unsigned RotateAmt;
   MVT RotateVT;
-  if (!isLegalBitRotate(SVN, DAG, Subtarget, RotateVT, RotateAmt))
+  if (!isLegalBitRotate(SVN->getMask(), VT, Subtarget, RotateVT, RotateAmt))
     return SDValue();
 
   SDValue Op = DAG.getBitcast(RotateVT, SVN->getOperand(0));
@@ -5142,7 +5138,7 @@
   // expansion for.
   unsigned RotateAmt;
   MVT RotateVT;
-  if (isLegalBitRotate(SVN, DAG, Subtarget, RotateVT, RotateAmt))
+  if (isLegalBitRotate(Mask, VT, Subtarget, RotateVT, RotateAmt))
     return SDValue();
 
   MVT ElemVT = VT.getVectorElementType();