[clang] [llvm] [RISCV][SiFive] Reduce intrinsics of SiFive VCIX extension (PR #79407)

[Craig Topper via llvm-commits]

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@@ -817,6 +817,66 @@ bool RISCVDAGToDAGISel::tryIndexedLoad(SDNode *Node) {
   return true;
 }
 
+void RISCVDAGToDAGISel::selectSF_VC_X_SE(SDNode *Node) {
+  if (!Subtarget->hasVInstructions())
+    return;
+
+  assert(Node->getOpcode() == ISD::INTRINSIC_VOID && "Unexpected opcode");
+
+  SDLoc DL(Node);
+  unsigned IntNo = Node->getConstantOperandVal(1);
+
+  assert((IntNo == Intrinsic::riscv_sf_vc_x_se ||
+          IntNo == Intrinsic::riscv_sf_vc_i_se) &&
+         "Unexpected vsetvli intrinsic");
+
+  // imm, imm, imm, simm5/scalar, sew, log2lmul, vl
+  auto *SewSDNode = dyn_cast<ConstantSDNode>(Node->getOperand(6));
+  unsigned Log2SEW = Log2_32(SewSDNode->getZExtValue());
+  SDValue SEWOp =
+      CurDAG->getTargetConstant(Log2SEW, DL, Subtarget->getXLenVT());
+  SmallVector<SDValue, 8> Operands = {Node->getOperand(2), Node->getOperand(3),
+                                      Node->getOperand(4), Node->getOperand(5),
+                                      Node->getOperand(8), SEWOp,
+                                      Node->getOperand(0)};
+
+  unsigned Opcode;
+  auto *LMulSDNode = dyn_cast<ConstantSDNode>(Node->getOperand(7));
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topperc wrote:

dyn_cast -> cast

https://github.com/llvm/llvm-project/pull/79407