diff --git a/clang/test/Preprocessor/riscv-target-features.c b/clang/test/Preprocessor/riscv-target-features.c
--- a/clang/test/Preprocessor/riscv-target-features.c
+++ b/clang/test/Preprocessor/riscv-target-features.c
@@ -45,6 +45,8 @@
 // CHECK-NOT: __riscv_zk
 // CHECK-NOT: __riscv_zicbom
 // CHECK-NOT: __riscv_zicboz
+// CHECK-NOT: __riscv_zca
+// CHECK-NOT: __riscv_zcb
 
 // RUN: %clang -target riscv32-unknown-linux-gnu -march=rv32im -x c -E -dM %s \
 // RUN: -o - | FileCheck --check-prefix=CHECK-M-EXT %s
@@ -462,3 +464,16 @@
 // RUN: %clang -target riscv64 -march=rv64izicbop -x c -E -dM %s \
 // RUN: -o - | FileCheck --check-prefix=CHECK-ZICBOP-EXT %s
 // CHECK-ZICBOP-EXT: __riscv_zicbop 1000000{{$}}
+
+// RUN: %clang -target riscv32 -march=rv32izca0p70 -menable-experimental-extensions \
+// RUN: -x c -E -dM %s -o - | FileCheck --check-prefix=CHECK-ZCA-EXT %s
+// RUN: %clang -target riscv64 -march=rv64izca0p70 -menable-experimental-extensions \
+// RUN: -x c -E -dM %s -o - | FileCheck --check-prefix=CHECK-ZCA-EXT %s
+// CHECK-ZCA-EXT: __riscv_zca 70000{{$}}
+
+// RUN: %clang -target riscv32 -march=rv32izcb0p70 -menable-experimental-extensions \
+// RUN: -x c -E -dM %s -o - | FileCheck --check-prefix=CHECK-ZCB-EXT %s
+// RUN: %clang -target riscv64 -march=rv64izcb0p70 -menable-experimental-extensions \
+// RUN: -x c -E -dM %s -o - | FileCheck --check-prefix=CHECK-ZCB-EXT %s
+// CHECK-ZCB-EXT: __riscv_zca 70000{{$}}
+// CHECK-ZCB-EXT: __riscv_zcb 70000{{$}}
diff --git a/llvm/lib/Support/RISCVISAInfo.cpp b/llvm/lib/Support/RISCVISAInfo.cpp
--- a/llvm/lib/Support/RISCVISAInfo.cpp
+++ b/llvm/lib/Support/RISCVISAInfo.cpp
@@ -113,6 +113,7 @@
     {"zbr", RISCVExtensionVersion{0, 93}},
     {"zbt", RISCVExtensionVersion{0, 93}},
     {"zca", RISCVExtensionVersion{0, 70}},
+    {"zcb", RISCVExtensionVersion{0, 70}},
     {"zvfh", RISCVExtensionVersion{0, 1}},
 };
 
@@ -778,6 +779,7 @@
 static const char *ImpliedExtsZkn[] = {"zbkb", "zbkc", "zbkx", "zkne", "zknd", "zknh"};
 static const char *ImpliedExtsZks[] = {"zbkb", "zbkc", "zbkx", "zksed", "zksh"};
 static const char *ImpliedExtsZvfh[] = {"zve32f"};
+static const char *ImpliedExtsZcb[] = {"zca"};
 
 struct ImpliedExtsEntry {
   StringLiteral Name;
@@ -793,6 +795,7 @@
 // Note: The table needs to be sorted by name.
 static constexpr ImpliedExtsEntry ImpliedExts[] = {
     {{"v"}, {ImpliedExtsV}},
+    {{"zcb"}, {ImpliedExtsZcb}},
     {{"zdinx"}, {ImpliedExtsZdinx}},
     {{"zfh"}, {ImpliedExtsZfh}},
     {{"zfhmin"}, {ImpliedExtsZfhmin}},
diff --git a/llvm/lib/Target/RISCV/AsmParser/RISCVAsmParser.cpp b/llvm/lib/Target/RISCV/AsmParser/RISCVAsmParser.cpp
--- a/llvm/lib/Target/RISCV/AsmParser/RISCVAsmParser.cpp
+++ b/llvm/lib/Target/RISCV/AsmParser/RISCVAsmParser.cpp
@@ -618,6 +618,16 @@
            VK == RISCVMCExpr::VK_RISCV_None;
   }
 
+  bool isUImm2Lsb0() const {
+    int64_t Imm;
+    RISCVMCExpr::VariantKind VK = RISCVMCExpr::VK_RISCV_None;
+    if (!isImm())
+      return false;
+    bool IsConstantImm = evaluateConstantImm(getImm(), Imm, VK);
+    return IsConstantImm && isShiftedUInt<1, 1>(Imm) &&
+           VK == RISCVMCExpr::VK_RISCV_None;
+  }
+
   bool isUImm7Lsb00() const {
     if (!isImm())
       return false;
@@ -1151,6 +1161,9 @@
     return generateImmOutOfRangeError(Operands, ErrorInfo, 0, (1 << 4) - 1);
   case Match_InvalidUImm2:
     return generateImmOutOfRangeError(Operands, ErrorInfo, 0, (1 << 2) - 1);
+  case Match_InvalidUImm2Lsb0:
+    return generateImmOutOfRangeError(Operands, ErrorInfo, 0, 2,
+                                      "immediate must be one of");
   case Match_InvalidUImm3:
     return generateImmOutOfRangeError(Operands, ErrorInfo, 0, (1 << 3) - 1);
   case Match_InvalidUImm5:
diff --git a/llvm/lib/Target/RISCV/RISCV.td b/llvm/lib/Target/RISCV/RISCV.td
--- a/llvm/lib/Target/RISCV/RISCV.td
+++ b/llvm/lib/Target/RISCV/RISCV.td
@@ -360,6 +360,14 @@
                                    "'C' (Compressed Instructions) or "
                                    "'Zca' (part of the C extension, excluding compressed floating point loads/stores)">;
 
+def FeatureExtZcb
+    : SubtargetFeature<"experimental-zcb", "HasStdExtZcb", "true",
+                       "'Zcb' (Shortened format for basic bit manipulation instructions)", 
+                       [FeatureExtZca]>;
+def HasStdExtZcb : Predicate<"Subtarget->hasStdExtZcb()">,
+                           AssemblerPredicate<(all_of FeatureExtZcb),
+                           "'Zcb' (Shortened format for basic bit manipulation instructions)">;
+
 def FeatureNoRVCHints
     : SubtargetFeature<"no-rvc-hints", "EnableRVCHintInstrs", "false",
                        "Disable RVC Hint Instructions.">;
diff --git a/llvm/lib/Target/RISCV/RISCVInstrInfo.td b/llvm/lib/Target/RISCV/RISCVInstrInfo.td
--- a/llvm/lib/Target/RISCV/RISCVInstrInfo.td
+++ b/llvm/lib/Target/RISCV/RISCVInstrInfo.td
@@ -1688,6 +1688,7 @@
 include "RISCVInstrInfoD.td"
 include "RISCVInstrInfoC.td"
 include "RISCVInstrInfoZb.td"
+include "RISCVInstrInfoZc.td"
 include "RISCVInstrInfoZk.td"
 include "RISCVInstrInfoV.td"
 include "RISCVInstrInfoZfh.td"
diff --git a/llvm/lib/Target/RISCV/RISCVInstrInfoZc.td b/llvm/lib/Target/RISCV/RISCVInstrInfoZc.td
new file mode 100644
--- /dev/null
+++ b/llvm/lib/Target/RISCV/RISCVInstrInfoZc.td
@@ -0,0 +1,227 @@
+//===-- RISCVInstrInfoZc.td - RISC-V 'Zc' instructions -----*- tablegen -*-===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+///
+/// This file describes the RISC-V instructions from the 'Zc' Code-size 
+/// reduction extension, version 0.70.4.
+/// This version is still experimental as the 'Zc' extension hasn't been
+/// ratified yet.
+///
+//===----------------------------------------------------------------------===//
+
+//===----------------------------------------------------------------------===//
+// Operand and SDNode transformation definitions.
+//===----------------------------------------------------------------------===//
+
+def uimm2_zc : Operand<XLenVT>,
+                 ImmLeaf<XLenVT, [{return isUInt<2>(Imm);}]> {
+  let ParserMatchClass = UImmAsmOperand<2>;
+  let DecoderMethod = "decodeUImmOperand<2>";
+  let OperandType = "OPERAND_UIMM2";
+  let OperandNamespace = "RISCVOp";
+  let MCOperandPredicate = [{
+    int64_t Imm;
+    if (!MCOp.evaluateAsConstantImm(Imm))
+      return false;
+    return isUInt<2>(Imm);
+  }];
+}
+
+def uimm2_lsb0 : Operand<XLenVT>,
+                 ImmLeaf<XLenVT, [{return isShiftedUInt<1, 1>(Imm);}]> {
+  let ParserMatchClass = UImmAsmOperand<2, "Lsb0">;
+  let EncoderMethod = "getImmOpValue";
+  let DecoderMethod = "decodeUImmOperand<2>";
+  let MCOperandPredicate = [{
+    int64_t Imm;
+    if (!MCOp.evaluateAsConstantImm(Imm))
+      return false;
+    return isShiftedUInt<1, 1>(Imm);
+  }];
+}
+
+//===----------------------------------------------------------------------===//
+// Instruction Class Templates
+//===----------------------------------------------------------------------===//
+
+let hasSideEffects = 0, mayLoad = 0, mayStore = 0 in
+class RVZcArith_r<bits<2> funct2, bits<3> opcode, string opcodestr>
+    : RVInst16<(outs GPRC:$rs_wb), (ins GPRC:$rs),
+                opcodestr, "$rs", [], InstFormatCB>{
+  bits<3> rs;
+  let Constraints = "$rs = $rs_wb";
+
+  let Inst{15-13} = 0b100;
+  let Inst{12-10} = 0b111;
+  let Inst{9-7} = rs;
+  let Inst{6-5} = funct2;
+  let Inst{4-2} = opcode;
+  let Inst{1-0} = 0b01;
+}
+
+let hasSideEffects = 0, mayLoad = 0, mayStore = 0 in
+class RVZcArith_rr<bits<6> funct6,bits<2> funct2, bits<2> opcode, string opcodestr>
+    : RVInst16<(outs GPRC:$rs1_wb), (ins GPRC:$rs1, GPRC:$rs2),
+                opcodestr, "$rs1, $rs2", [], InstFormatCB> {
+  bits<3> rs1;
+  bits<3> rs2;
+  let Constraints = "$rs1 = $rs1_wb";
+
+  let Inst{15-10} = funct6;
+  let Inst{9-7} = rs1;
+  let Inst{6-5} = funct2;
+  let Inst{4-2} = rs2;
+  let Inst{1-0} = opcode;
+}
+
+let hasSideEffects = 0, mayLoad = 1, mayStore = 0 in
+class ZcLoad_ri<bits<3> funct3, bits<2> opcode, string opcodestr,
+                 RegisterClass cls, DAGOperand opnd>
+    : RVInst16CL<funct3, opcode, (outs cls:$rd), (ins GPRC:$rs1, opnd:$imm),
+                 opcodestr, "$rd, ${imm}(${rs1})">;
+
+let hasSideEffects = 0, mayLoad = 0, mayStore = 1 in
+class ZcStore_ri<bits<3> funct3, bits<2> opcode, string opcodestr,
+                 RegisterClass cls, DAGOperand opnd>
+    : RVInst16CS<funct3, opcode, (outs), (ins cls:$rs2, GPRC:$rs1, opnd:$imm),
+                 opcodestr, "$rs2, ${imm}(${rs1})">;
+
+//===----------------------------------------------------------------------===//
+// Instructions
+//===----------------------------------------------------------------------===//
+
+let Predicates = [HasStdExtZcb, HasStdExtZba, IsRV64] in {
+def C_ZEXT_W  : RVZcArith_r<0b11, 0b100 , "c.zext.w">,
+                Sched<[WriteIALU32, ReadIALU32, ReadIALU32]>;
+}
+
+let Predicates = [HasStdExtZcb, HasStdExtZbb] in {
+def C_ZEXT_H  : RVZcArith_r<0b11, 0b010 , "c.zext.h">,
+                Sched<[WriteIALU, ReadIALU]>;
+def C_SEXT_B  : RVZcArith_r<0b11, 0b001 , "c.sext.b">,
+                Sched<[WriteIALU, ReadIALU]>;
+def C_SEXT_H  : RVZcArith_r<0b11, 0b011 , "c.sext.h">,
+                Sched<[WriteIALU, ReadIALU]>;
+}
+
+let Predicates = [HasStdExtZcb] in
+def C_ZEXT_B  : RVZcArith_r<0b11, 0b000 , "c.zext.b">,
+                Sched<[WriteIALU, ReadIALU]>;
+
+let Predicates = [HasStdExtZcb, HasStdExtMOrZmmul] in
+def C_MUL     : RVZcArith_rr<0b100111, 0b10, 0b01, "c.mul">,
+                Sched<[WriteIMul, ReadIMul, ReadIMul]>;
+
+let Predicates = [HasStdExtZcb] in {
+def C_NOT : RVZcArith_r<0b11, 0b101 , "c.not">,
+            Sched<[WriteIALU, ReadIALU]>;
+
+def C_LBU : ZcLoad_ri<0b100, 0b00, "c.lbu", GPRC, uimm2_zc>,
+            Sched<[WriteLDB, ReadMemBase]> {
+  bits<2> imm;
+
+  let Inst{12-10} = 0b000;
+  let Inst{6-5} = imm{0,1};
+}
+
+def C_LHU : ZcLoad_ri<0b100, 0b00, "c.lhu", GPRC, uimm2_lsb0>,
+            Sched<[WriteLDH, ReadMemBase]> {
+  bits<2> imm;
+
+  let Inst{12-10} = 0b001;
+  let Inst{6} = 0b0;
+  let Inst{5} = imm{1};
+}
+
+def C_LH  : ZcLoad_ri<0b100, 0b00, "c.lh", GPRC, uimm2_lsb0>,
+            Sched<[WriteLDH, ReadMemBase]> {
+  bits<2> imm;
+
+  let Inst{12-10} = 0b001;
+  let Inst{6} = 0b1;
+  let Inst{5} = imm{1};
+}
+
+def C_SB  : ZcStore_ri<0b100, 0b00, "c.sb", GPRC, uimm2_zc>,
+            Sched<[WriteSTB, ReadStoreData, ReadMemBase]> {
+  bits<2> imm;
+
+  let Inst{12-10} = 0b010;
+  let Inst{6-5} = imm{0,1};
+}
+
+def C_SH  : ZcStore_ri<0b100, 0b00, "c.sh", GPRC, uimm2_lsb0>, 
+            Sched<[WriteSTH, ReadStoreData, ReadMemBase]> {
+  bits<2> imm;
+
+  let Inst{12-10} = 0b011;
+  let Inst{6} = 0b1;
+  let Inst{5} = imm{1};
+}
+}
+
+let Predicates = [HasStdExtZcb, HasStdExtMOrZmmul] in{
+def : CompressPat<(MUL GPRC:$rs1, GPRC:$rs1, GPRC:$rs2),
+                  (C_MUL GPRC:$rs1, GPRC:$rs2)>;
+def : CompressPat<(MUL GPRC:$rs1, GPRC:$rs2, GPRC:$rs1),
+                  (C_MUL GPRC:$rs1, GPRC:$rs2)>;
+} // Predicates = [HasStdExtZcb, HasStdExtMOrZmmul]
+
+let Predicates = [HasStdExtZcb, HasStdExtZbb] in{
+def : CompressPat<(SEXT_B GPRC:$rs1, GPRC:$rs1),
+                  (C_SEXT_B GPRC:$rs1, GPRC:$rs1)>;
+def : CompressPat<(SEXT_H GPRC:$rs1, GPRC:$rs1),
+                  (C_SEXT_H GPRC:$rs1, GPRC:$rs1)>;
+} // Predicates = [HasStdExtZcb, HasStdExtZbb]
+
+let Predicates = [HasStdExtZcb, HasStdExtZbb] in{
+def : CompressPat<(ZEXT_H_RV32 GPRC:$rs1, GPRC:$rs1),
+                  (C_ZEXT_H GPRC:$rs1, GPRC:$rs1)>;
+def : CompressPat<(ZEXT_H_RV64 GPRC:$rs1, GPRC:$rs1),
+                  (C_ZEXT_H GPRC:$rs1, GPRC:$rs1)>;
+} // Predicates = [HasStdExtZcb, HasStdExtZbb]
+
+let Predicates = [HasStdExtZcb] in{
+def : CompressPat<(ANDI GPRC:$rs1, GPRC:$rs1, 255),
+                  (C_ZEXT_B GPRC:$rs1, GPRC:$rs1)>;
+} // Predicates = [HasStdExtZcb]
+
+let Predicates = [HasStdExtZcb, HasStdExtZba, IsRV64] in{
+def : CompressPat<(ADD_UW GPRC:$rs1, GPRC:$rs1, X0),
+                  (C_ZEXT_W GPRC:$rs1, GPRC:$rs1)>;
+} // Predicates = [HasStdExtZcb, HasStdExtZba, IsRV64]
+
+let Predicates = [HasStdExtZcb] in{
+def : CompressPat<(XORI GPRC:$rs1, GPRC:$rs1, -1),
+                  (C_NOT GPRC:$rs1, GPRC:$rs1)>;
+}
+
+let Predicates = [HasStdExtZcb] in{
+def : CompressPat<(LBU GPRC:$rd, GPRC:$rs1, uimm2_zc:$imm),
+                  (C_LBU GPRC:$rd, GPRC:$rs1, uimm2_zc:$imm)>;
+def : CompressPat<(LHU GPRC:$rd, GPRC:$rs1, uimm2_lsb0:$imm),
+                  (C_LHU GPRC:$rd, GPRC:$rs1, uimm2_lsb0:$imm)>;
+def : CompressPat<(LH GPRC:$rd, GPRC:$rs1, uimm2_lsb0:$imm),
+                  (C_LH GPRC:$rd, GPRC:$rs1, uimm2_lsb0:$imm)>;
+def : CompressPat<(SB GPRC:$rs2, GPRC:$rs1, uimm2_zc:$imm),
+                  (C_SB GPRC:$rs2, GPRC:$rs1, uimm2_zc:$imm)>;
+def : CompressPat<(SH GPRC:$rs2, GPRC:$rs1, uimm2_lsb0:$imm),
+                  (C_SH GPRC:$rs2, GPRC:$rs1, uimm2_lsb0:$imm)>;
+}// Predicates = [HasStdExtZcb]
+
+
+//===----------------------------------------------------------------------===//
+// Pseudo Instructions
+//===----------------------------------------------------------------------===//
+
+let Predicates = [HasStdExtZcb] in {
+def : InstAlias<"c.lbu $rd, (${rs1})",(C_LW GPRC:$rd, GPRC:$rs1, 0)>;
+def : InstAlias<"c.lhu $rd, (${rs1})",(C_LW GPRC:$rd, GPRC:$rs1, 0)>;
+def : InstAlias<"c.lh $rd, (${rs1})", (C_LW GPRC:$rd, GPRC:$rs1, 0)>;
+def : InstAlias<"c.sb $rd, (${rs1})", (C_LW GPRC:$rd, GPRC:$rs1, 0)>;
+def : InstAlias<"c.sh $rd, (${rs1})", (C_LW GPRC:$rd, GPRC:$rs1, 0)>;
+}
diff --git a/llvm/lib/Target/RISCV/RISCVSubtarget.h b/llvm/lib/Target/RISCV/RISCVSubtarget.h
--- a/llvm/lib/Target/RISCV/RISCVSubtarget.h
+++ b/llvm/lib/Target/RISCV/RISCVSubtarget.h
@@ -62,6 +62,7 @@
   bool HasStdExtZbs = false;
   bool HasStdExtZbt = false;
   bool HasStdExtZca = false;
+  bool HasStdExtZcb = false;
   bool HasStdExtV = false;
   bool HasStdExtZve32x = false;
   bool HasStdExtZve32f = false;
@@ -171,6 +172,7 @@
   bool hasStdExtZbs() const { return HasStdExtZbs; }
   bool hasStdExtZbt() const { return HasStdExtZbt; }
   bool hasStdExtZca() const { return HasStdExtZca; }
+  bool hasStdExtZcb() const { return HasStdExtZcb; }
   bool hasStdExtZvl() const { return ZvlLen != 0; }
   bool hasStdExtZvfh() const { return HasStdExtZvfh; }
   bool hasStdExtZfhmin() const { return HasStdExtZfhmin; }
diff --git a/llvm/test/CodeGen/RISCV/attributes.ll b/llvm/test/CodeGen/RISCV/attributes.ll
--- a/llvm/test/CodeGen/RISCV/attributes.ll
+++ b/llvm/test/CodeGen/RISCV/attributes.ll
@@ -42,6 +42,8 @@
 ; RUN: llc -mtriple=riscv32 -mattr=+zicbom %s -o - | FileCheck --check-prefix=RV32ZICBOM %s
 ; RUN: llc -mtriple=riscv32 -mattr=+zicboz %s -o - | FileCheck --check-prefix=RV32ZICBOZ %s
 ; RUN: llc -mtriple=riscv32 -mattr=+zicbop %s -o - | FileCheck --check-prefix=RV32ZICBOP %s
+; RUN: llc -mtriple=riscv32 -mattr=+experimental-zcb %s -o - | FileCheck --check-prefix=RV32ZCB %s
+
 ; RUN: llc -mtriple=riscv64 -mattr=+m %s -o - | FileCheck --check-prefix=RV64M %s
 ; RUN: llc -mtriple=riscv64 -mattr=+zmmul %s -o - | FileCheck --check-prefix=RV64ZMMUL %s
 ; RUN: llc -mtriple=riscv64 -mattr=+m,+zmmul %s -o - | FileCheck --check-prefix=RV64MZMMUL %s
@@ -84,6 +86,7 @@
 ; RUN: llc -mtriple=riscv64 -mattr=+zicbom %s -o - | FileCheck --check-prefix=RV64ZICBOM %s
 ; RUN: llc -mtriple=riscv64 -mattr=+zicboz %s -o - | FileCheck --check-prefix=RV64ZICBOZ %s
 ; RUN: llc -mtriple=riscv64 -mattr=+zicbop %s -o - | FileCheck --check-prefix=RV64ZICBOP %s
+; RUN: llc -mtriple=riscv64 -mattr=+experimental-zcb %s -o - | FileCheck --check-prefix=RV64ZCB %s
 
 ; RV32M: .attribute 5, "rv32i2p0_m2p0"
 ; RV32ZMMUL: .attribute 5, "rv32i2p0_zmmul1p0"
@@ -127,6 +130,7 @@
 ; RV32ZICBOM: .attribute 5, "rv32i2p0_zicbom1p0"
 ; RV32ZICBOZ: .attribute 5, "rv32i2p0_zicboz1p0"
 ; RV32ZICBOP: .attribute 5, "rv32i2p0_zicbop1p0"
+; RV32ZCB: .attribute 5, "rv32i2p0_zca0p70_zcb0p70"
 
 ; RV64M: .attribute 5, "rv64i2p0_m2p0"
 ; RV64ZMMUL: .attribute 5, "rv64i2p0_zmmul1p0"
@@ -170,6 +174,7 @@
 ; RV64ZICBOM: .attribute 5, "rv64i2p0_zicbom1p0"
 ; RV64ZICBOZ: .attribute 5, "rv64i2p0_zicboz1p0"
 ; RV64ZICBOP: .attribute 5, "rv64i2p0_zicbop1p0"
+; RV64ZCB: .attribute 5, "rv64i2p0_zca0p70_zcb0p70"
 
 define i32 @addi(i32 %a) {
   %1 = add i32 %a, 1
diff --git a/llvm/test/MC/RISCV/attribute-arch.s b/llvm/test/MC/RISCV/attribute-arch.s
--- a/llvm/test/MC/RISCV/attribute-arch.s
+++ b/llvm/test/MC/RISCV/attribute-arch.s
@@ -190,3 +190,6 @@
 
 .attribute arch, "rv32izca0p70"
 # CHECK: attribute      5, "rv32i2p0_zca0p70"
+
+.attribute arch, "rv32izcb0p70"
+# CHECK: attribute      5, "rv32i2p0_zca0p70_zcb0p70"
diff --git a/llvm/test/MC/RISCV/rv32zcb-invalid.s b/llvm/test/MC/RISCV/rv32zcb-invalid.s
new file mode 100644
--- /dev/null
+++ b/llvm/test/MC/RISCV/rv32zcb-invalid.s
@@ -0,0 +1,19 @@
+# RUN: not llvm-mc -triple=riscv32 -mattr=experimental-zcb -riscv-no-aliases -show-encoding %s 2>&1 \
+# RUN:     | FileCheck -check-prefixes=CHECK-ERROR %s
+# RUN: not llvm-mc -triple=riscv64 -mattr=experimental-zcb -riscv-no-aliases -show-encoding < %s 2>&1 \
+# RUN:     | FileCheck -check-prefixes=CHECK-ERROR %s
+
+# CHECK-ERROR: error: immediate must be an integer in the range [0, 3]
+c.lbu a5, 10(a4)
+
+# CHECK-ERROR: error: immediate must be one of [0, 2]
+c.lhu a5, 10(a4)
+
+# CHECK-ERROR: error: immediate must be one of [0, 2]
+c.lh a5, 10(a4)
+
+# CHECK-ERROR: error: immediate must be an integer in the range [0, 3]
+c.sb a5, 10(a4)
+
+# CHECK-ERROR: error: immediate must be one of [0, 2]
+c.sh a5, 10(a4)
diff --git a/llvm/test/MC/RISCV/rv32zcb-valid.s b/llvm/test/MC/RISCV/rv32zcb-valid.s
new file mode 100644
--- /dev/null
+++ b/llvm/test/MC/RISCV/rv32zcb-valid.s
@@ -0,0 +1,148 @@
+# RUN: llvm-mc %s -triple=riscv32 -mattr=+m,+zbb,+zba,+experimental-zcb -riscv-no-aliases -show-encoding \
+# RUN:     | FileCheck -check-prefixes=CHECK-ASM,CHECK-ASM-AND-OBJ %s
+# RUN: llvm-mc -filetype=obj -triple=riscv32 -mattr=+m,+zbb,+zba,+experimental-zcb < %s \
+# RUN:     | llvm-objdump --mattr=+m,+zbb,+zba,+experimental-zcb -M no-aliases -d -r - \
+# RUN:     | FileCheck --check-prefixes=CHECK-ASM-AND-OBJ %s
+# RUN: llvm-mc %s -triple=riscv64 -mattr=+m,+zbb,+zba,+experimental-zcb -riscv-no-aliases -show-encoding \
+# RUN:     | FileCheck -check-prefixes=CHECK-ASM,CHECK-ASM-AND-OBJ %s
+# RUN: llvm-mc -filetype=obj -triple=riscv64 -mattr=+m,+zbb,+zba,+experimental-zcb < %s \
+# RUN:     | llvm-objdump --mattr=+m,+zbb,+zba,experimental-zcb -M no-aliases -d -r - \
+# RUN:     | FileCheck --check-prefixes=CHECK-ASM-AND-OBJ %s
+#
+# RUN: not llvm-mc -triple riscv64 \
+# RUN:     -riscv-no-aliases -show-encoding < %s 2>&1 \
+# RUN:     | FileCheck -check-prefixes=CHECK-NO-EXT %s
+# RUN: not llvm-mc -triple riscv64 \
+# RUN:     -riscv-no-aliases -show-encoding < %s 2>&1 \
+# RUN:     | FileCheck -check-prefixes=CHECK-NO-EXT %s
+
+# CHECK-ASM-AND-OBJ: c.zext.b s0
+# CHECK-ASM: encoding: [0x61,0x9c]
+# CHECK-NO-EXT: error: instruction requires the following: 'Zcb' (Shortened format for basic bit manipulation instructions)
+c.zext.b s0
+
+# CHECK-ASM-AND-OBJ: c.sext.b s0
+# CHECK-ASM: encoding: [0x65,0x9c]
+# CHECK-NO-EXT: error: instruction requires the following: 'Zbb' (Basic Bit-Manipulation), 'Zcb' (Shortened format for basic bit manipulation instructions){{$}}
+c.sext.b s0
+
+# CHECK-ASM-AND-OBJ: c.zext.h s0
+# CHECK-ASM: encoding: [0x69,0x9c]
+# CHECK-NO-EXT: error: instruction requires the following: 'Zbb' (Basic Bit-Manipulation), 'Zcb' (Shortened format for basic bit manipulation instructions){{$}}
+c.zext.h s0
+
+# CHECK-ASM-AND-OBJ: c.sext.h s0
+# CHECK-ASM: encoding: [0x6d,0x9c]
+# CHECK-NO-EXT: error: instruction requires the following: 'Zbb' (Basic Bit-Manipulation), 'Zcb' (Shortened format for basic bit manipulation instructions){{$}}
+c.sext.h s0
+
+# CHECK-ASM-AND-OBJ: c.not s0
+# CHECK-ASM: encoding: [0x75,0x9c]
+# CHECK-NO-EXT: error: instruction requires the following: 'Zcb' (Shortened format for basic bit manipulation instructions){{$}}
+c.not s0
+
+# CHECK-ASM-AND-OBJ: c.mul s0, s1
+# CHECK-ASM: encoding: [0x45,0x9c]
+# CHECK-NO-EXT: error: instruction requires the following: 'M' (Integer Multiplication and Division) or 'Zmmul' (Integer Multiplication), 'Zcb' (Shortened format for basic bit manipulation instructions){{$}}
+c.mul s0, s1
+
+# CHECK-ASM-AND-OBJ: c.lbu a5, 2(a4)
+# CHECK-ASM: encoding: [0x3c,0x83]
+# CHECK-NO-EXT: error: instruction requires the following: 'Zcb' (Shortened format for basic bit manipulation instructions){{$}}
+c.lbu a5, 2(a4)
+
+# CHECK-ASM-AND-OBJ: c.lhu a5, 2(a4)
+# CHECK-ASM: encoding: [0x3c,0x87]
+# CHECK-NO-EXT: error: instruction requires the following: 'Zcb' (Shortened format for basic bit manipulation instructions){{$}}
+c.lhu a5, 2(a4)
+
+# CHECK-ASM-AND-OBJ: c.lh a5, 2(a4)
+# CHECK-ASM: encoding: [0x7c,0x87]
+# CHECK-NO-EXT: error: instruction requires the following: 'Zcb' (Shortened format for basic bit manipulation instructions){{$}}
+c.lh a5, 2(a4)
+
+# CHECK-ASM-AND-OBJ: c.sb a5, 2(a4)
+# CHECK-ASM: encoding: [0x3c,0x8b]
+# CHECK-NO-EXT: error: instruction requires the following: 'Zcb' (Shortened format for basic bit manipulation instructions){{$}}
+c.sb a5, 2(a4)
+
+# CHECK-ASM-AND-OBJ: c.sh a5, 2(a4)
+# CHECK-ASM: encoding: [0x7c,0x8f]
+# CHECK-NO-EXT: error: instruction requires the following: 'Zcb' (Shortened format for basic bit manipulation instructions){{$}}
+c.sh a5, 2(a4)
+
+# CHECK-ASM-AND-OBJ: c.mul s0, s1
+# CHECK-ASM: encoding: [0x45,0x9c]
+mul s0, s1, s0
+
+# CHECK-ASM-AND-OBJ: c.mul s0, s1
+# CHECK-ASM: encoding: [0x45,0x9c]
+mul s0, s0, s1
+
+# CHECK-ASM-AND-OBJ: c.sext.b s0
+# CHECK-ASM: encoding: [0x65,0x9c]
+sext.b s0, s0
+
+# CHECK-ASM-AND-OBJ: c.sext.h s0
+# CHECK-ASM: encoding: [0x6d,0x9c]
+sext.h s0, s0
+
+# CHECK-ASM-AND-OBJ: c.zext.h s0
+# CHECK-ASM: encoding: [0x69,0x9c]
+zext.h s0, s0
+
+# CHECK-ASM-AND-OBJ: c.zext.b s0
+# CHECK-ASM: encoding: [0x61,0x9c]
+ANDI s0, s0, 255
+
+# CHECK-ASM-AND-OBJ: c.not s0
+# CHECK-ASM: encoding: [0x75,0x9c]
+xori s0, s0, -1
+
+# CHECK-ASM-AND-OBJ: c.lh a5, 2(a4)
+# CHECK-ASM: encoding: [0x7c,0x87]
+lh a5, 2(a4)
+
+# CHECK-ASM-AND-OBJ: c.lbu a5, 2(a4)
+# CHECK-ASM: encoding: [0x3c,0x83]
+lbu a5, 2(a4)
+
+# CHECK-ASM-AND-OBJ: c.lhu a5, 2(a4)
+# CHECK-ASM: encoding: [0x3c,0x87]
+lhu a5, 2(a4)
+
+# CHECK-ASM-AND-OBJ: c.sb a5, 2(a4)
+# CHECK-ASM: encoding: [0x3c,0x8b]
+sb a5, 2(a4)
+
+# CHECK-ASM-AND-OBJ: c.sh a5, 2(a4)
+# CHECK-ASM: encoding: [0x7c,0x8f]
+sh a5, 2(a4)
+
+# CHECK-ASM-AND-OBJ: lh a5, 3(a4)
+# CHECK-ASM: encoding: [0x83,0x17,0x37,0x00]
+lh a5, 3(a4)
+
+# CHECK-ASM-AND-OBJ: lbu a5, 4(a4)
+# CHECK-ASM: encoding: [0x83,0x47,0x47,0x00]
+lbu a5, 4(a4)
+
+# CHECK-ASM-AND-OBJ: lhu a5, 3(a4)
+# CHECK-ASM: encoding: [0x83,0x57,0x37,0x00]
+lhu a5, 3(a4)
+
+# CHECK-ASM-AND-OBJ: sb a5, 4(a4)
+# CHECK-ASM: encoding: [0x23,0x02,0xf7,0x00]
+sb a5, 4(a4)
+
+# CHECK-ASM-AND-OBJ: sh a5, 3(a4)
+# CHECK-ASM: encoding: [0xa3,0x11,0xf7,0x00]
+sh a5, 3(a4)
+
+# CHECK-ASM-AND-OBJ: addi s0, s0, 0
+# CHECK-ASM: encoding: [0x13,0x04,0x04,0x00]
+ADDI s0, s0, 0
+
+# CHECK-ASM-AND-OBJ: xori s0, s0, 1
+# CHECK-ASM: encoding: [0x13,0x44,0x14,0x00]
+xori s0, s0, 1
diff --git a/llvm/test/MC/RISCV/rv64zcb-valid.s b/llvm/test/MC/RISCV/rv64zcb-valid.s
new file mode 100644
--- /dev/null
+++ b/llvm/test/MC/RISCV/rv64zcb-valid.s
@@ -0,0 +1,22 @@
+# RUN: llvm-mc %s -triple=riscv64 -mattr=+m,+zbb,+zba,+experimental-zcb -riscv-no-aliases -show-encoding \
+# RUN:     | FileCheck -check-prefixes=CHECK-ASM,CHECK-ASM-AND-OBJ %s
+# RUN: llvm-mc -filetype=obj -triple=riscv64 -mattr=+m,+zbb,+zba,+experimental-zcb < %s \
+# RUN:     | llvm-objdump --mattr=+m,+zbb,+zba,experimental-zcb -M no-aliases -d -r - \
+# RUN:     | FileCheck --check-prefixes=CHECK-ASM-AND-OBJ %s
+#
+# RUN: not llvm-mc -triple riscv64 \
+# RUN:     -riscv-no-aliases -show-encoding < %s 2>&1 \
+# RUN:     | FileCheck -check-prefixes=CHECK-NO-EXT %s
+# RUN: not llvm-mc -triple riscv32 -mattr=+m,+zbb,+zba,+experimental-zcb \
+# RUN:     -riscv-no-aliases -show-encoding < %s 2>&1 \
+# RUN:     | FileCheck -check-prefixes=CHECK-NO-RV64 %s
+
+# CHECK-ASM-AND-OBJ: c.zext.w s0
+# CHECK-ASM: encoding: [0x71,0x9c]
+# CHECK-NO-EXT: error: instruction requires the following: 'Zba' (Address Generation Instructions), 'Zcb' (Shortened format for basic bit manipulation instructions) 
+# CHECK-NO-RV64: error: instruction requires the following: RV64I Base Instruction Set
+c.zext.w s0
+
+# CHECK-ASM-AND-OBJ: c.zext.w s0
+# CHECK-ASM: encoding: [0x71,0x9c]
+add.uw s0, s0, zero