Index: llvm/trunk/lib/CodeGen/SelectionDAG/LegalizeIntegerTypes.cpp
===================================================================
--- llvm/trunk/lib/CodeGen/SelectionDAG/LegalizeIntegerTypes.cpp
+++ llvm/trunk/lib/CodeGen/SelectionDAG/LegalizeIntegerTypes.cpp
@@ -1045,6 +1045,8 @@
 
   case ISD::FRAMEADDR:
   case ISD::RETURNADDR: Res = PromoteIntOp_FRAMERETURNADDR(N); break;
+
+  case ISD::PREFETCH: Res = PromoteIntOp_PREFETCH(N, OpNo); break;
   }
 
   // If the result is null, the sub-method took care of registering results etc.
@@ -1410,6 +1412,18 @@
   return SDValue(DAG.UpdateNodeOperands(N, Op), 0);
 }
 
+SDValue DAGTypeLegalizer::PromoteIntOp_PREFETCH(SDNode *N, unsigned OpNo) {
+  assert(OpNo > 1 && "Don't know how to promote this operand!");
+  // Promote the rw, locality, and cache type arguments to a supported integer
+  // width.
+  SDValue Op2 = ZExtPromotedInteger(N->getOperand(2));
+  SDValue Op3 = ZExtPromotedInteger(N->getOperand(3));
+  SDValue Op4 = ZExtPromotedInteger(N->getOperand(4));
+  return SDValue(DAG.UpdateNodeOperands(N, N->getOperand(0), N->getOperand(1),
+                                        Op2, Op3, Op4),
+                 0);
+}
+
 //===----------------------------------------------------------------------===//
 //  Integer Result Expansion
 //===----------------------------------------------------------------------===//
Index: llvm/trunk/lib/CodeGen/SelectionDAG/LegalizeTypes.h
===================================================================
--- llvm/trunk/lib/CodeGen/SelectionDAG/LegalizeTypes.h
+++ llvm/trunk/lib/CodeGen/SelectionDAG/LegalizeTypes.h
@@ -376,6 +376,7 @@
   SDValue PromoteIntOp_MGATHER(MaskedGatherSDNode *N, unsigned OpNo);
   SDValue PromoteIntOp_ADDSUBCARRY(SDNode *N, unsigned OpNo);
   SDValue PromoteIntOp_FRAMERETURNADDR(SDNode *N);
+  SDValue PromoteIntOp_PREFETCH(SDNode *N, unsigned OpNo);
 
   void PromoteSetCCOperands(SDValue &LHS,SDValue &RHS, ISD::CondCode Code);
 
Index: llvm/trunk/test/CodeGen/RISCV/prefetch.ll
===================================================================
--- llvm/trunk/test/CodeGen/RISCV/prefetch.ll
+++ llvm/trunk/test/CodeGen/RISCV/prefetch.ll
@@ -0,0 +1,19 @@
+; NOTE: Assertions have been autogenerated by utils/update_llc_test_checks.py
+; RUN: llc -mtriple=riscv32 -verify-machineinstrs < %s \
+; RUN:   | FileCheck -check-prefix=RV32I %s
+; RUN: llc -mtriple=riscv64 -verify-machineinstrs < %s \
+; RUN:   | FileCheck -check-prefix=RV64I %s
+
+declare void @llvm.prefetch(i8*, i32, i32, i32)
+
+define void @test_prefetch(i8* %a) nounwind {
+; RV32I-LABEL: test_prefetch:
+; RV32I:       # %bb.0:
+; RV32I-NEXT:    ret
+;
+; RV64I-LABEL: test_prefetch:
+; RV64I:       # %bb.0:
+; RV64I-NEXT:    ret
+  call void @llvm.prefetch(i8* %a, i32 0, i32 1, i32 2)
+  ret void
+}