[llvm] [RISCV] Support llvm.masked.expandload intrinsic (PR #101954)

[Craig Topper via llvm-commits]

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@@ -10760,16 +10763,49 @@ SDValue RISCVTargetLowering::lowerMaskedLoad(SDValue Op,
   if (!VL)
     VL = getDefaultVLOps(VT, ContainerVT, DL, DAG, Subtarget).second;
 
-  unsigned IntID =
-      IsUnmasked ? Intrinsic::riscv_vle : Intrinsic::riscv_vle_mask;
+  SDValue Index;
+  if (!IsUnmasked && IsExpandingLoad) {
+    MVT IndexVT = ContainerVT;
+    if (ContainerVT.isFloatingPoint())
+      IndexVT = IndexVT.changeVectorElementTypeToInteger();
+
+    MVT IndexEltVT = IndexVT.getVectorElementType();
+    if (Subtarget.isRV32() && IndexEltVT.bitsGT(XLenVT))
+      IndexVT = IndexVT.changeVectorElementType(XLenVT);
+
+    // If index vector is an i8 vector and the element count exceeds 256, we
+    // should change the element type of index vector to i16 to avoid overflow.
+    if (IndexEltVT == MVT::i8 &&
+        VT.getVectorElementCount().getKnownMinValue() > 256) {
+      // FIXME: Don't know how to make LMUL==8 case legal.
+      assert(getLMUL(IndexVT) != RISCVII::LMUL_8 &&
+             "We don't know how to lower LMUL==8 case");
+      IndexVT = IndexVT.changeVectorElementType(MVT::i16);
+    }
+
+    Index = DAG.getNode(ISD::INTRINSIC_WO_CHAIN, DL, IndexVT,
+                        DAG.getConstant(Intrinsic::riscv_viota, DL, XLenVT),
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topperc wrote:

getTargetConstant

https://github.com/llvm/llvm-project/pull/101954