[llvm] [RISCV][GISel] Support select indexed vector load store intrinsics (PR #165876)

[Matt Arsenault via llvm-commits]

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@@ -805,6 +808,69 @@ bool RISCVInstructionSelector::selectIntrinsicWithSideEffects(
     I.eraseFromParent();
     return constrainSelectedInstRegOperands(*PseudoMI, TII, TRI, RBI);
   }
+  case Intrinsic::riscv_vloxei:
+  case Intrinsic::riscv_vloxei_mask:
+  case Intrinsic::riscv_vluxei:
+  case Intrinsic::riscv_vluxei_mask: {
+    bool IsMasked = IntrinID == Intrinsic::riscv_vloxei_mask ||
+                    IntrinID == Intrinsic::riscv_vluxei_mask;
+    bool IsOrdered = IntrinID == Intrinsic::riscv_vloxei ||
+                     IntrinID == Intrinsic::riscv_vloxei_mask;
+    LLT VT = MRI->getType(I.getOperand(0).getReg());
+    unsigned Log2SEW = Log2_32(VT.getScalarSizeInBits());
+
+    // Result vector
+    const Register DstReg = I.getOperand(0).getReg();
+
+    // Sources
+    bool HasPassthruOperand = IntrinID != Intrinsic::riscv_vlm;
+    unsigned CurOp = 2;
+    SmallVector<SrcOp, 4> SrcOps; // Source registers.
+
+    // Passthru
+    if (HasPassthruOperand) {
+      auto PassthruReg = I.getOperand(CurOp++).getReg();
+      SrcOps.push_back(PassthruReg);
+    } else {
+      SrcOps.push_back(Register(RISCV::NoRegister));
+    }
+    LLT IndexVT;
+    addVectorLoadStoreOperands(I, SrcOps, CurOp, IsMasked, true, &IndexVT);
+
+    RISCVVType::VLMUL LMUL = RISCVTargetLowering::getLMUL(getMVTForLLT(VT));
+    RISCVVType::VLMUL IndexLMUL =
+        RISCVTargetLowering::getLMUL(getMVTForLLT(IndexVT));
+    unsigned IndexLog2EEW = Log2_32(IndexVT.getScalarSizeInBits());
+    if (IndexLog2EEW == 6 && !Subtarget->is64Bit()) {
+      report_fatal_error("The V extension does not support EEW=64 for index "
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arsenm wrote:

report_fatal_error is deprecated, this should probably be using reportFatalUsageError (or will this fail the legalizer rules?)

https://github.com/llvm/llvm-project/pull/165876