diff --git a/clang/include/clang/Basic/BuiltinsRISCV.def b/clang/include/clang/Basic/BuiltinsRISCV.def
--- a/clang/include/clang/Basic/BuiltinsRISCV.def
+++ b/clang/include/clang/Basic/BuiltinsRISCV.def
@@ -18,6 +18,8 @@
 // Zbb extension
 TARGET_BUILTIN(__builtin_riscv_orc_b_32, "ZiZi", "nc", "zbb")
 TARGET_BUILTIN(__builtin_riscv_orc_b_64, "WiWi", "nc", "zbb,64bit")
+TARGET_BUILTIN(__builtin_riscv_clz_32, "ZiZi", "nc", "zbb")
+TARGET_BUILTIN(__builtin_riscv_clz_64, "WiWi", "nc", "zbb,64bit")
 
 // Zbc or Zbkc extension
 TARGET_BUILTIN(__builtin_riscv_clmul, "LiLiLi", "nc", "zbc|zbkc")
diff --git a/clang/lib/CodeGen/CGBuiltin.cpp b/clang/lib/CodeGen/CGBuiltin.cpp
--- a/clang/lib/CodeGen/CGBuiltin.cpp
+++ b/clang/lib/CodeGen/CGBuiltin.cpp
@@ -18799,6 +18799,8 @@
   default: llvm_unreachable("unexpected builtin ID");
   case RISCV::BI__builtin_riscv_orc_b_32:
   case RISCV::BI__builtin_riscv_orc_b_64:
+  case RISCV::BI__builtin_riscv_clz_32:
+  case RISCV::BI__builtin_riscv_clz_64:
   case RISCV::BI__builtin_riscv_clmul:
   case RISCV::BI__builtin_riscv_clmulh:
   case RISCV::BI__builtin_riscv_clmulr:
@@ -18844,6 +18846,10 @@
     case RISCV::BI__builtin_riscv_orc_b_64:
       ID = Intrinsic::riscv_orc_b;
       break;
+    case RISCV::BI__builtin_riscv_clz_32:
+    case RISCV::BI__builtin_riscv_clz_64:
+      ID = Intrinsic::riscv_clz;
+      break;
 
     // Zbc
     case RISCV::BI__builtin_riscv_clmul:
diff --git a/clang/test/CodeGen/RISCV/rvb-intrinsics/riscv32-zbb.c b/clang/test/CodeGen/RISCV/rvb-intrinsics/riscv32-zbb.c
--- a/clang/test/CodeGen/RISCV/rvb-intrinsics/riscv32-zbb.c
+++ b/clang/test/CodeGen/RISCV/rvb-intrinsics/riscv32-zbb.c
@@ -13,3 +13,14 @@
 int orc_b_32(int a) {
   return __builtin_riscv_orc_b_32(a);
 }
+// RV32ZBB-LABEL: @clz_32(
+// RV32ZBB-NEXT:  entry:
+// RV32ZBB-NEXT:    [[A_ADDR:%.*]] = alloca i32, align 4
+// RV32ZBB-NEXT:    store i32 [[A:%.*]], i32* [[A_ADDR]], align 4
+// RV32ZBB-NEXT:    [[TMP0:%.*]] = load i32, i32* [[A_ADDR]], align 4
+// RV32ZBB-NEXT:    [[TMP1:%.*]] = call i32 @llvm.riscv.clz.i32(i32 [[TMP0]])
+// RV32ZBB-NEXT:    ret i32 [[TMP1]]
+//
+int clz_32(int a) {
+  return __builtin_riscv_clz_32(a);
+}
diff --git a/clang/test/CodeGen/RISCV/rvb-intrinsics/riscv64-zbb.c b/clang/test/CodeGen/RISCV/rvb-intrinsics/riscv64-zbb.c
--- a/clang/test/CodeGen/RISCV/rvb-intrinsics/riscv64-zbb.c
+++ b/clang/test/CodeGen/RISCV/rvb-intrinsics/riscv64-zbb.c
@@ -25,3 +25,27 @@
 long orc_b_64(long a) {
   return __builtin_riscv_orc_b_64(a);
 }
+
+// RV64ZBB-LABEL: @clz_32(
+// RV64ZBB-NEXT:  entry:
+// RV64ZBB-NEXT:    [[A_ADDR:%.*]] = alloca i32, align 4
+// RV64ZBB-NEXT:    store i32 [[A:%.*]], i32* [[A_ADDR]], align 4
+// RV64ZBB-NEXT:    [[TMP0:%.*]] = load i32, i32* [[A_ADDR]], align 4
+// RV64ZBB-NEXT:    [[TMP1:%.*]] = call i32 @llvm.riscv.clz.i32(i32 [[TMP0]])
+// RV64ZBB-NEXT:    ret i32 [[TMP1]]
+//
+int clz_32(int a) {
+  return __builtin_riscv_clz_32(a);
+}
+
+// RV64ZBB-LABEL: @clz_64(
+// RV64ZBB-NEXT:  entry:
+// RV64ZBB-NEXT:    [[A_ADDR:%.*]] = alloca i64, align 8
+// RV64ZBB-NEXT:    store i64 [[A:%.*]], i64* [[A_ADDR]], align 8
+// RV64ZBB-NEXT:    [[TMP0:%.*]] = load i64, i64* [[A_ADDR]], align 8
+// RV64ZBB-NEXT:    [[TMP1:%.*]] = call i64 @llvm.riscv.clz.i64(i64 [[TMP0]])
+// RV64ZBB-NEXT:    ret i64 [[TMP1]]
+//
+long clz_64(long a) {
+  return __builtin_riscv_clz_64(a);
+}
diff --git a/llvm/include/llvm/IR/IntrinsicsRISCV.td b/llvm/include/llvm/IR/IntrinsicsRISCV.td
--- a/llvm/include/llvm/IR/IntrinsicsRISCV.td
+++ b/llvm/include/llvm/IR/IntrinsicsRISCV.td
@@ -87,6 +87,7 @@
 
   // Zbb
   def int_riscv_orc_b : BitManipGPRIntrinsics;
+  def int_riscv_clz : BitManipGPRIntrinsics;
 
   // Zbc or Zbkc
   def int_riscv_clmul  : BitManipGPRGPRIntrinsics;
diff --git a/llvm/lib/Target/RISCV/RISCVInstrInfoZb.td b/llvm/lib/Target/RISCV/RISCVInstrInfoZb.td
--- a/llvm/lib/Target/RISCV/RISCVInstrInfoZb.td
+++ b/llvm/lib/Target/RISCV/RISCVInstrInfoZb.td
@@ -1213,3 +1213,7 @@
 def : PatGprGpr<int_riscv_xperm4, XPERM4>;
 def : PatGprGpr<int_riscv_xperm8, XPERM8>;
 }
+let Predicates = [HasStdExtZbb] in {
+def : PatGpr<int_riscv_clz, CLZ>;
+}
+
diff --git a/llvm/test/CodeGen/RISCV/rv32zbb-intrinsic.ll b/llvm/test/CodeGen/RISCV/rv32zbb-intrinsic.ll
--- a/llvm/test/CodeGen/RISCV/rv32zbb-intrinsic.ll
+++ b/llvm/test/CodeGen/RISCV/rv32zbb-intrinsic.ll
@@ -12,3 +12,13 @@
   %tmp = call i32 @llvm.riscv.orc.b.i32(i32 %a)
   ret i32 %tmp
 }
+declare i32 @llvm.riscv.clz.i32(i32)
+
+define i32 @clz(i32 %a) nounwind {
+; RV32ZBB-LABEL: clz:
+; RV32ZBB:       # %bb.0:
+; RV32ZBB-NEXT:    clz a0, a0
+; RV32ZBB-NEXT:    ret
+  %tmp = call i32 @llvm.riscv.clz.i32(i32 %a)
+  ret i32 %tmp
+}
diff --git a/llvm/test/CodeGen/RISCV/rv64zbb-intrinsic.ll b/llvm/test/CodeGen/RISCV/rv64zbb-intrinsic.ll
--- a/llvm/test/CodeGen/RISCV/rv64zbb-intrinsic.ll
+++ b/llvm/test/CodeGen/RISCV/rv64zbb-intrinsic.ll
@@ -54,3 +54,14 @@
   %tmp = call i64 @llvm.riscv.orc.b.i64(i64 %a)
   ret i64 %tmp
 }
+
+declare i64 @llvm.riscv.clz.i64(i64)
+
+define i64 @clz64(i64 %a) nounwind {
+; RV64ZBB-LABEL: clz64:
+; RV64ZBB:       # %bb.0:
+; RV64ZBB-NEXT:    clz a0, a0
+; RV64ZBB-NEXT:    ret
+  %tmp = call i64 @llvm.riscv.clz.i64(i64 %a)
+  ret i64 %tmp
+}