diff --git a/llvm/lib/Target/RISCV/MCTargetDesc/RISCVFixupKinds.h b/llvm/lib/Target/RISCV/MCTargetDesc/RISCVFixupKinds.h
--- a/llvm/lib/Target/RISCV/MCTargetDesc/RISCVFixupKinds.h
+++ b/llvm/lib/Target/RISCV/MCTargetDesc/RISCVFixupKinds.h
@@ -13,8 +13,7 @@
 
 #undef RISCV
 
-namespace llvm {
-namespace RISCV {
+namespace llvm::RISCV {
 enum Fixups {
   // 20-bit fixup corresponding to %hi(foo) for instructions like lui
   fixup_riscv_hi20 = FirstTargetFixupKind,
@@ -109,7 +108,6 @@
   fixup_riscv_invalid,
   NumTargetFixupKinds = fixup_riscv_invalid - FirstTargetFixupKind
 };
-} // end namespace RISCV
-} // end namespace llvm
+} // end namespace llvm::RISCV
 
 #endif
diff --git a/llvm/lib/Target/RISCV/MCTargetDesc/RISCVMatInt.cpp b/llvm/lib/Target/RISCV/MCTargetDesc/RISCVMatInt.cpp
--- a/llvm/lib/Target/RISCV/MCTargetDesc/RISCVMatInt.cpp
+++ b/llvm/lib/Target/RISCV/MCTargetDesc/RISCVMatInt.cpp
@@ -172,8 +172,7 @@
   return 0;
 }
 
-namespace llvm {
-namespace RISCVMatInt {
+namespace llvm::RISCVMatInt {
 InstSeq generateInstSeq(int64_t Val, const FeatureBitset &ActiveFeatures) {
   RISCVMatInt::InstSeq Res;
   generateInstSeqImpl(Val, ActiveFeatures, Res);
@@ -419,5 +418,4 @@
   }
 }
 
-} // namespace RISCVMatInt
-} // namespace llvm
+} // namespace llvm::RISCVMatInt
diff --git a/llvm/lib/Target/RISCV/RISCVISelDAGToDAG.cpp b/llvm/lib/Target/RISCV/RISCVISelDAGToDAG.cpp
--- a/llvm/lib/Target/RISCV/RISCVISelDAGToDAG.cpp
+++ b/llvm/lib/Target/RISCV/RISCVISelDAGToDAG.cpp
@@ -27,8 +27,7 @@
 
 #define DEBUG_TYPE "riscv-isel"
 
-namespace llvm {
-namespace RISCV {
+namespace llvm::RISCV {
 #define GET_RISCVVSSEGTable_IMPL
 #define GET_RISCVVLSEGTable_IMPL
 #define GET_RISCVVLXSEGTable_IMPL
@@ -39,8 +38,7 @@
 #define GET_RISCVVSXTable_IMPL
 #define GET_RISCVMaskedPseudosTable_IMPL
 #include "RISCVGenSearchableTables.inc"
-} // namespace RISCV
-} // namespace llvm
+} // namespace llvm::RISCV
 
 void RISCVDAGToDAGISel::PreprocessISelDAG() {
   SelectionDAG::allnodes_iterator Position = CurDAG->allnodes_end();
diff --git a/llvm/lib/Target/RISCV/RISCVISelLowering.cpp b/llvm/lib/Target/RISCV/RISCVISelLowering.cpp
--- a/llvm/lib/Target/RISCV/RISCVISelLowering.cpp
+++ b/llvm/lib/Target/RISCV/RISCVISelLowering.cpp
@@ -12833,12 +12833,9 @@
   return Reg;
 }
 
-namespace llvm {
-namespace RISCVVIntrinsicsTable {
+namespace llvm::RISCVVIntrinsicsTable {
 
 #define GET_RISCVVIntrinsicsTable_IMPL
 #include "RISCVGenSearchableTables.inc"
 
-} // namespace RISCVVIntrinsicsTable
-
-} // namespace llvm
+} // namespace llvm::RISCVVIntrinsicsTable
diff --git a/llvm/lib/Target/RISCV/RISCVInstrInfo.cpp b/llvm/lib/Target/RISCV/RISCVInstrInfo.cpp
--- a/llvm/lib/Target/RISCV/RISCVInstrInfo.cpp
+++ b/llvm/lib/Target/RISCV/RISCVInstrInfo.cpp
@@ -42,16 +42,14 @@
     "riscv-prefer-whole-register-move", cl::init(false), cl::Hidden,
     cl::desc("Prefer whole register move for vector registers."));
 
-namespace llvm {
-namespace RISCVVPseudosTable {
+namespace llvm::RISCVVPseudosTable {
 
 using namespace RISCV;
 
 #define GET_RISCVVPseudosTable_IMPL
 #include "RISCVGenSearchableTables.inc"
 
-} // namespace RISCVVPseudosTable
-} // namespace llvm
+} // namespace llvm::RISCVVPseudosTable
 
 RISCVInstrInfo::RISCVInstrInfo(RISCVSubtarget &STI)
     : RISCVGenInstrInfo(RISCV::ADJCALLSTACKDOWN, RISCV::ADJCALLSTACKUP),