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
@@ -110,6 +110,7 @@
     {"zbp", RISCVExtensionVersion{0, 93}},
     {"zbr", RISCVExtensionVersion{0, 93}},
     {"zbt", RISCVExtensionVersion{0, 93}},
+    {"zca", RISCVExtensionVersion{0, 70}},
     {"zvfh", RISCVExtensionVersion{0, 1}},
 };
 
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
@@ -340,6 +340,19 @@
                         FeatureStdExtZkr,
                         FeatureStdExtZkt]>;
 
+def FeatureExtZca
+    : SubtargetFeature<"experimental-zca", "HasStdExtZca", "true",
+                       "'Zca' (part of the C extension, excluding compressed floating point loads/stores)">;
+def HasStdExtZca : Predicate<"Subtarget->hasStdExtZca()">,
+                           AssemblerPredicate<(all_of FeatureExtZca),
+                           "'Zca' (part of the C extension, excluding compressed floating point loads/stores)">;
+
+def HasStdExtCOrZca
+    : Predicate<"Subtarget->hasStdExtC() || Subtarget->hasStdExtZca()">,
+                AssemblerPredicate<(any_of FeatureStdExtC, FeatureExtZca),
+                                   "'C' (Compressed Instructions) or "
+                                   "'Zca' (part of the C extension, excluding compressed floating point loads/stores)">;
+
 def FeatureNoRVCHints
     : SubtargetFeature<"no-rvc-hints", "EnableRVCHintInstrs", "false",
                        "Disable RVC Hint Instructions.">;
diff --git a/llvm/lib/Target/RISCV/RISCVInstrInfoC.td b/llvm/lib/Target/RISCV/RISCVInstrInfoC.td
--- a/llvm/lib/Target/RISCV/RISCVInstrInfoC.td
+++ b/llvm/lib/Target/RISCV/RISCVInstrInfoC.td
@@ -281,7 +281,7 @@
 // Instructions
 //===----------------------------------------------------------------------===//
 
-let Predicates = [HasStdExtC] in {
+let Predicates = [HasStdExtCOrZca] in {
 
 let hasSideEffects = 0, mayLoad = 0, mayStore = 0, Uses = [X2] in
 def C_ADDI4SPN : RVInst16CIW<0b000, 0b00, (outs GPRC:$rd),
@@ -321,7 +321,7 @@
   let Inst{5} = imm{6};
 }
 
-let Predicates = [HasStdExtC, IsRV64] in
+let Predicates = [HasStdExtCOrZca, IsRV64] in
 def C_LD : CLoad_ri<0b011, "c.ld", GPRC, uimm8_lsb000>,
            Sched<[WriteLDD, ReadMemBase]> {
   bits<8> imm;
@@ -355,7 +355,7 @@
   let Inst{5} = imm{6};
 }
 
-let Predicates = [HasStdExtC, IsRV64] in
+let Predicates = [HasStdExtCOrZca, IsRV64] in
 def C_SD : CStore_rri<0b111, "c.sd", GPRC, uimm8_lsb000>,
            Sched<[WriteSTD, ReadStoreData, ReadMemBase]> {
   bits<8> imm;
@@ -391,12 +391,12 @@
 
 let hasSideEffects = 0, mayLoad = 0, mayStore = 0, isCall = 1,
     DecoderNamespace = "RISCV32Only_", Defs = [X1],
-    Predicates = [HasStdExtC, IsRV32]  in
+    Predicates = [HasStdExtCOrZca, IsRV32]  in
 def C_JAL : RVInst16CJ<0b001, 0b01, (outs), (ins simm12_lsb0:$offset),
                        "c.jal", "$offset">, Sched<[WriteJal]>;
 
 let hasSideEffects = 0, mayLoad = 0, mayStore = 0,
-    Predicates = [HasStdExtC, IsRV64] in
+    Predicates = [HasStdExtCOrZca, IsRV64] in
 def C_ADDIW : RVInst16CI<0b001, 0b01, (outs GPRNoX0:$rd_wb),
                          (ins GPRNoX0:$rd, simm6:$imm),
                          "c.addiw", "$rd, $imm">,
@@ -458,7 +458,7 @@
 def C_AND  : CS_ALU<0b100011, 0b11, "c.and", GPRC>,
              Sched<[WriteIALU, ReadIALU, ReadIALU]>;
 
-let Predicates = [HasStdExtC, IsRV64] in {
+let Predicates = [HasStdExtCOrZca, IsRV64] in {
 def C_SUBW : CS_ALU<0b100111, 0b00, "c.subw", GPRC>,
              Sched<[WriteIALU32, ReadIALU32, ReadIALU32]>;
 def C_ADDW : CS_ALU<0b100111, 0b01, "c.addw", GPRC>,
@@ -506,7 +506,7 @@
   let Inst{3-2} = imm{7-6};
 }
 
-let Predicates = [HasStdExtC, IsRV64] in
+let Predicates = [HasStdExtCOrZca, IsRV64] in
 def C_LDSP : CStackLoad<0b011, "c.ldsp", GPRNoX0, uimm9_lsb000>,
              Sched<[WriteLDD, ReadMemBase]> {
   let Inst{6-5} = imm{4-3};
@@ -566,7 +566,7 @@
   let Inst{8-7}  = imm{7-6};
 }
 
-let Predicates = [HasStdExtC, IsRV64] in
+let Predicates = [HasStdExtCOrZca, IsRV64] in
 def C_SDSP : CStackStore<0b111, "c.sdsp", GPR, uimm9_lsb000>,
              Sched<[WriteSTD, ReadStoreData, ReadMemBase]> {
   let Inst{12-10} = imm{5-3};
@@ -581,13 +581,13 @@
   let Inst{15-0} = 0;
 }
 
-} // Predicates = [HasStdExtC]
+} // Predicates = [HasStdExtCOrZca]
 
 //===----------------------------------------------------------------------===//
 // HINT Instructions
 //===----------------------------------------------------------------------===//
 
-let Predicates = [HasStdExtC, HasRVCHints], hasSideEffects = 0, mayLoad = 0,
+let Predicates = [HasStdExtCOrZca, HasRVCHints], hasSideEffects = 0, mayLoad = 0,
     mayStore = 0 in
 {
 
@@ -688,7 +688,7 @@
   let Inst{12} = 0;
 }
 
-} // Predicates = [HasStdExtC, HasRVCHints], hasSideEffects = 0, mayLoad = 0,
+} // Predicates = [HasStdExtCOrZca, HasRVCHints], hasSideEffects = 0, mayLoad = 0,
   // mayStore = 0
 
 //===----------------------------------------------------------------------===//
@@ -696,14 +696,14 @@
 //===----------------------------------------------------------------------===//
 
 let EmitPriority = 0 in {
-let Predicates = [HasStdExtC] in {
+let Predicates = [HasStdExtCOrZca] in {
 def : InstAlias<"c.lw $rd, (${rs1})", (C_LW GPRC:$rd, GPRC:$rs1, 0)>;
 def : InstAlias<"c.sw $rs2, (${rs1})", (C_SW GPRC:$rs2, GPRC:$rs1, 0)>;
 def : InstAlias<"c.lwsp $rd, (${rs1})", (C_LWSP GPRC:$rd, SP:$rs1, 0)>;
 def : InstAlias<"c.swsp $rs2, (${rs1})", (C_SWSP GPRC:$rs2, SP:$rs1, 0)>;
 }
 
-let Predicates = [HasStdExtC, IsRV64] in {
+let Predicates = [HasStdExtCOrZca, IsRV64] in {
 def : InstAlias<"c.ld $rd, (${rs1})", (C_LD GPRC:$rd, GPRC:$rs1, 0)>;
 def : InstAlias<"c.sd $rs2, (${rs1})", (C_SD GPRC:$rs2, GPRC:$rs1, 0)>;
 def : InstAlias<"c.ldsp $rd, (${rs1})", (C_LDSP GPRC:$rd, SP:$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
@@ -60,6 +60,7 @@
   bool HasStdExtZbr = false;
   bool HasStdExtZbs = false;
   bool HasStdExtZbt = false;
+  bool HasStdExtZca = false;
   bool HasStdExtV = false;
   bool HasStdExtZve32x = false;
   bool HasStdExtZve32f = false;
@@ -166,6 +167,7 @@
   bool hasStdExtZbr() const { return HasStdExtZbr; }
   bool hasStdExtZbs() const { return HasStdExtZbs; }
   bool hasStdExtZbt() const { return HasStdExtZbt; }
+  bool hasStdExtZca() const { return HasStdExtZca; }
   bool hasStdExtZvl() const { return ZvlLen != 0; }
   bool hasStdExtZvfh() const { return HasStdExtZvfh; }
   bool hasStdExtZfhmin() const { return HasStdExtZfhmin; }
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
@@ -187,3 +187,6 @@
 
 .attribute arch, "rv32if_zkt1p0_zve32f1p0_zve32x1p0_zvl32b1p0"
 # CHECK: attribute      5, "rv32i2p0_f2p0_zkt1p0_zve32f1p0_zve32x1p0_zvl32b1p0"
+
+.attribute arch, "rv32izca0p70"
+# CHECK: attribute      5, "rv32i2p0_zca0p70"
diff --git a/llvm/test/MC/RISCV/rv32c-invalid.s b/llvm/test/MC/RISCV/rv32c-invalid.s
--- a/llvm/test/MC/RISCV/rv32c-invalid.s
+++ b/llvm/test/MC/RISCV/rv32c-invalid.s
@@ -1,5 +1,7 @@
 # RUN: not llvm-mc -triple=riscv32 -mattr=+c -mattr=+no-rvc-hints < %s 2>&1 \
 # RUN:     | FileCheck %s
+# RUN: not llvm-mc -triple=riscv32 -mattr=+experimental-zca -mattr=+no-rvc-hints < %s 2>&1 \
+# RUN:     | FileCheck %s
 
 ## GPRC
 .LBB:
diff --git a/llvm/test/MC/RISCV/rv32c-only-valid.s b/llvm/test/MC/RISCV/rv32c-only-valid.s
--- a/llvm/test/MC/RISCV/rv32c-only-valid.s
+++ b/llvm/test/MC/RISCV/rv32c-only-valid.s
@@ -17,7 +17,7 @@
 # CHECK-OBJ: c.jal 0x7fe
 # CHECK-ASM: c.jal 2046
 # CHECK-ASM: encoding: [0xfd,0x2f]
-# CHECK-NO-EXT: error: instruction requires the following: 'C' (Compressed Instructions){{$}}
+# CHECK-NO-EXT: error: instruction requires the following: 'C' (Compressed Instructions) or 'Zca' (part of the C extension, excluding compressed floating point loads/stores){{$}}
 # CHECK-NO-RV32: error: instruction requires the following: RV32I Base Instruction Set{{$}}
-# CHECK-NO-RV32-AND-EXT: error: instruction requires the following: 'C' (Compressed Instructions), RV32I Base Instruction Set{{$}}
+# CHECK-NO-RV32-AND-EXT: error: instruction requires the following: 'C' (Compressed Instructions) or 'Zca' (part of the C extension, excluding compressed floating point loads/stores), RV32I Base Instruction Set{{$}}
 c.jal 2046
diff --git a/llvm/test/MC/RISCV/rv32c-valid.s b/llvm/test/MC/RISCV/rv32c-valid.s
--- a/llvm/test/MC/RISCV/rv32c-valid.s
+++ b/llvm/test/MC/RISCV/rv32c-valid.s
@@ -3,11 +3,21 @@
 # RUN: llvm-mc -filetype=obj -triple=riscv32 -mattr=+c < %s \
 # RUN:     | llvm-objdump --mattr=+c -M no-aliases -d -r - \
 # RUN:     | FileCheck --check-prefixes=CHECK-OBJ,CHECK-ASM-AND-OBJ %s
+# RUN: llvm-mc %s -triple=riscv32 -mattr=+experimental-zca -riscv-no-aliases -show-encoding \
+# RUN:     | FileCheck -check-prefixes=CHECK-ASM,CHECK-ASM-AND-OBJ %s
+# RUN: llvm-mc -filetype=obj -triple=riscv32 -mattr=+experimental-zca < %s \
+# RUN:     | llvm-objdump --mattr=+experimental-zca -M no-aliases -d -r - \
+# RUN:     | FileCheck --check-prefixes=CHECK-OBJ,CHECK-ASM-AND-OBJ %s
 # RUN: llvm-mc %s -triple=riscv64 -mattr=+c -riscv-no-aliases -show-encoding \
 # RUN:     | FileCheck -check-prefixes=CHECK-ASM,CHECK-ASM-AND-OBJ %s
 # RUN: llvm-mc -filetype=obj -triple=riscv64 -mattr=+c < %s \
 # RUN:     | llvm-objdump --mattr=+c -M no-aliases -d -r - \
 # RUN:     | FileCheck --check-prefix=CHECK-ASM-AND-OBJ %s
+# RUN: llvm-mc %s -triple=riscv64 -mattr=+experimental-zca -riscv-no-aliases -show-encoding \
+# RUN:     | FileCheck -check-prefixes=CHECK-ASM,CHECK-ASM-AND-OBJ %s
+# RUN: llvm-mc -filetype=obj -triple=riscv64 -mattr=+experimental-zca < %s \
+# RUN:     | llvm-objdump --mattr=+experimental-zca -M no-aliases -d -r - \
+# RUN:     | FileCheck --check-prefix=CHECK-ASM-AND-OBJ %s
 
 # RUN: not llvm-mc -triple riscv32 \
 # RUN:     -riscv-no-aliases -show-encoding < %s 2>&1 \
@@ -17,147 +27,147 @@
 
 # CHECK-ASM-AND-OBJ: c.lwsp ra, 0(sp)
 # CHECK-ASM: encoding: [0x82,0x40]
-# CHECK-NO-EXT:  error: instruction requires the following: 'C' (Compressed Instructions){{$}}
+# CHECK-NO-EXT:  error: instruction requires the following: 'C' (Compressed Instructions) or 'Zca' (part of the C extension, excluding compressed floating point loads/stores){{$}}
 c.lwsp ra, 0(sp)
 # CHECK-ASM-AND-OBJ: c.swsp ra, 252(sp)
 # CHECK-ASM: encoding: [0x86,0xdf]
-# CHECK-NO-EXT:  error: instruction requires the following: 'C' (Compressed Instructions){{$}}
+# CHECK-NO-EXT:  error: instruction requires the following: 'C' (Compressed Instructions) or 'Zca' (part of the C extension, excluding compressed floating point loads/stores){{$}}
 c.swsp ra, 252(sp)
 # CHECK-ASM-AND-OBJ: c.lw a2, 0(a0)
 # CHECK-ASM: encoding: [0x10,0x41]
-# CHECK-NO-EXT:  error: instruction requires the following: 'C' (Compressed Instructions){{$}}
+# CHECK-NO-EXT:  error: instruction requires the following: 'C' (Compressed Instructions) or 'Zca' (part of the C extension, excluding compressed floating point loads/stores){{$}}
 c.lw a2, 0(a0)
 # CHECK-ASM-AND-OBJ: c.sw a5, 124(a3)
 # CHECK-ASM: encoding: [0xfc,0xde]
-# CHECK-NO-EXT:  error: instruction requires the following: 'C' (Compressed Instructions){{$}}
+# CHECK-NO-EXT:  error: instruction requires the following: 'C' (Compressed Instructions) or 'Zca' (part of the C extension, excluding compressed floating point loads/stores){{$}}
 c.sw a5, 124(a3)
 
 # CHECK-ASM-AND-OBJ: c.lwsp s0, 0(sp)
 # CHECK-ASM: encoding: [0x02,0x44]
-# CHECK-NO-EXT:  error: instruction requires the following: 'C' (Compressed Instructions){{$}}
+# CHECK-NO-EXT:  error: instruction requires the following: 'C' (Compressed Instructions) or 'Zca' (part of the C extension, excluding compressed floating point loads/stores){{$}}
 c.lwsp x8, (x2)
 # CHECK-ASM-AND-OBJ: c.swsp s0, 0(sp)
 # CHECK-ASM: encoding: [0x22,0xc0]
-# CHECK-NO-EXT:  error: instruction requires the following: 'C' (Compressed Instructions){{$}}
+# CHECK-NO-EXT:  error: instruction requires the following: 'C' (Compressed Instructions) or 'Zca' (part of the C extension, excluding compressed floating point loads/stores){{$}}
 c.swsp x8, (x2)
 # CHECK-ASM-AND-OBJ: c.lw s0, 0(s1)
 # CHECK-ASM: encoding: [0x80,0x40]
-# CHECK-NO-EXT:  error: instruction requires the following: 'C' (Compressed Instructions){{$}}
+# CHECK-NO-EXT:  error: instruction requires the following: 'C' (Compressed Instructions) or 'Zca' (part of the C extension, excluding compressed floating point loads/stores){{$}}
 c.lw x8, (x9)
 # CHECK-ASM-AND-OBJ: c.sw s0, 0(s1)
 # CHECK-ASM: encoding: [0x80,0xc0]
-# CHECK-NO-EXT:  error: instruction requires the following: 'C' (Compressed Instructions){{$}}
+# CHECK-NO-EXT:  error: instruction requires the following: 'C' (Compressed Instructions) or 'Zca' (part of the C extension, excluding compressed floating point loads/stores){{$}}
 c.sw x8, (x9)
 
 # CHECK-OBJ: c.j 0xfffff810
 # CHECK-ASM: c.j -2048
 # CHECK-ASM: encoding: [0x01,0xb0]
-# CHECK-NO-EXT:  error: instruction requires the following: 'C' (Compressed Instructions){{$}}
+# CHECK-NO-EXT:  error: instruction requires the following: 'C' (Compressed Instructions) or 'Zca' (part of the C extension, excluding compressed floating point loads/stores){{$}}
 c.j -2048
 # CHECK-ASM-AND-OBJ: c.jr a7
 # CHECK-ASM: encoding: [0x82,0x88]
-# CHECK-NO-EXT:  error: instruction requires the following: 'C' (Compressed Instructions){{$}}
+# CHECK-NO-EXT:  error: instruction requires the following: 'C' (Compressed Instructions) or 'Zca' (part of the C extension, excluding compressed floating point loads/stores){{$}}
 c.jr a7
 # CHECK-ASM-AND-OBJ: c.jalr a1
 # CHECK-ASM: encoding: [0x82,0x95]
-# CHECK-NO-EXT:  error: instruction requires the following: 'C' (Compressed Instructions){{$}}
+# CHECK-NO-EXT:  error: instruction requires the following: 'C' (Compressed Instructions) or 'Zca' (part of the C extension, excluding compressed floating point loads/stores){{$}}
 c.jalr a1
 # CHECK-OBJ: c.beqz a3, 0xffffff16
 # CHECK-ASM: c.beqz a3, -256
 # CHECK-ASM: encoding: [0x81,0xd2]
-# CHECK-NO-EXT:  error: instruction requires the following: 'C' (Compressed Instructions){{$}}
+# CHECK-NO-EXT:  error: instruction requires the following: 'C' (Compressed Instructions) or 'Zca' (part of the C extension, excluding compressed floating point loads/stores){{$}}
 c.beqz a3, -256
 # CHECK-OBJ: c.bnez a5, 0x116
 # CHECK-ASM: c.bnez a5, 254
 # CHECK-ASM: encoding: [0xfd,0xef]
-# CHECK-NO-EXT:  error: instruction requires the following: 'C' (Compressed Instructions){{$}}
+# CHECK-NO-EXT:  error: instruction requires the following: 'C' (Compressed Instructions) or 'Zca' (part of the C extension, excluding compressed floating point loads/stores){{$}}
 c.bnez a5,  254
 
 # CHECK-ASM-AND-OBJ: c.li a7, 31
 # CHECK-ASM: encoding: [0xfd,0x48]
-# CHECK-NO-EXT:  error: instruction requires the following: 'C' (Compressed Instructions){{$}}
+# CHECK-NO-EXT:  error: instruction requires the following: 'C' (Compressed Instructions) or 'Zca' (part of the C extension, excluding compressed floating point loads/stores){{$}}
 c.li a7, 31
 # CHECK-ASM-AND-OBJ: c.addi a3, -32
 # CHECK-ASM: encoding: [0x81,0x16]
-# CHECK-NO-EXT:  error: instruction requires the following: 'C' (Compressed Instructions){{$}}
+# CHECK-NO-EXT:  error: instruction requires the following: 'C' (Compressed Instructions) or 'Zca' (part of the C extension, excluding compressed floating point loads/stores){{$}}
 c.addi a3, -32
 # CHECK-ASM-AND-OBJ: c.addi16sp sp, -512
 # CHECK-ASM: encoding: [0x01,0x71]
-# CHECK-NO-EXT:  error: instruction requires the following: 'C' (Compressed Instructions){{$}}
+# CHECK-NO-EXT:  error: instruction requires the following: 'C' (Compressed Instructions) or 'Zca' (part of the C extension, excluding compressed floating point loads/stores){{$}}
 c.addi16sp sp, -512
 # CHECK-ASM-AND-OBJ: c.addi16sp sp, 496
 # CHECK-ASM: encoding: [0x7d,0x61]
-# CHECK-NO-EXT:  error: instruction requires the following: 'C' (Compressed Instructions){{$}}
+# CHECK-NO-EXT:  error: instruction requires the following: 'C' (Compressed Instructions) or 'Zca' (part of the C extension, excluding compressed floating point loads/stores){{$}}
 c.addi16sp sp, 496
 # CHECK-ASM-AND-OBJ: c.addi4spn a3, sp, 1020
 # CHECK-ASM: encoding: [0xf4,0x1f]
-# CHECK-NO-EXT:  error: instruction requires the following: 'C' (Compressed Instructions){{$}}
+# CHECK-NO-EXT:  error: instruction requires the following: 'C' (Compressed Instructions) or 'Zca' (part of the C extension, excluding compressed floating point loads/stores){{$}}
 c.addi4spn a3, sp, 1020
 # CHECK-ASM-AND-OBJ: c.addi4spn a3, sp, 4
 # CHECK-ASM: encoding: [0x54,0x00]
-# CHECK-NO-EXT:  error: instruction requires the following: 'C' (Compressed Instructions){{$}}
+# CHECK-NO-EXT:  error: instruction requires the following: 'C' (Compressed Instructions) or 'Zca' (part of the C extension, excluding compressed floating point loads/stores){{$}}
 c.addi4spn a3, sp, 4
 # CHECK-ASM-AND-OBJ: c.slli a1, 1
 # CHECK-ASM: encoding: [0x86,0x05]
-# CHECK-NO-EXT:  error: instruction requires the following: 'C' (Compressed Instructions){{$}}
+# CHECK-NO-EXT:  error: instruction requires the following: 'C' (Compressed Instructions) or 'Zca' (part of the C extension, excluding compressed floating point loads/stores){{$}}
 c.slli a1, 1
 # CHECK-ASM-AND-OBJ: c.srli a3, 31
 # CHECK-ASM: encoding: [0xfd,0x82]
-# CHECK-NO-EXT:  error: instruction requires the following: 'C' (Compressed Instructions){{$}}
+# CHECK-NO-EXT:  error: instruction requires the following: 'C' (Compressed Instructions) or 'Zca' (part of the C extension, excluding compressed floating point loads/stores){{$}}
 c.srli a3, 31
 # CHECK-ASM-AND-OBJ: c.srai a4, 2
 # CHECK-ASM: encoding: [0x09,0x87]
-# CHECK-NO-EXT:  error: instruction requires the following: 'C' (Compressed Instructions){{$}}
+# CHECK-NO-EXT:  error: instruction requires the following: 'C' (Compressed Instructions) or 'Zca' (part of the C extension, excluding compressed floating point loads/stores){{$}}
 c.srai a4, 2
 # CHECK-ASM-AND-OBJ: c.andi a5, 15
 # CHECK-ASM: encoding: [0xbd,0x8b]
-# CHECK-NO-EXT:  error: instruction requires the following: 'C' (Compressed Instructions){{$}}
+# CHECK-NO-EXT:  error: instruction requires the following: 'C' (Compressed Instructions) or 'Zca' (part of the C extension, excluding compressed floating point loads/stores){{$}}
 c.andi a5, 15
 # CHECK-ASM-AND-OBJ: c.mv a7, s0
 # CHECK-ASM: encoding: [0xa2,0x88]
-# CHECK-NO-EXT:  error: instruction requires the following: 'C' (Compressed Instructions){{$}}
+# CHECK-NO-EXT:  error: instruction requires the following: 'C' (Compressed Instructions) or 'Zca' (part of the C extension, excluding compressed floating point loads/stores){{$}}
 c.mv a7, s0
 # CHECK-ASM-AND-OBJ: c.and a1, a2
 # CHECK-ASM: encoding: [0xf1,0x8d]
-# CHECK-NO-EXT:  error: instruction requires the following: 'C' (Compressed Instructions){{$}}
+# CHECK-NO-EXT:  error: instruction requires the following: 'C' (Compressed Instructions) or 'Zca' (part of the C extension, excluding compressed floating point loads/stores){{$}}
 c.and a1, a2
 # CHECK-ASM-AND-OBJ: c.or a2, a3
 # CHECK-ASM: encoding: [0x55,0x8e]
-# CHECK-NO-EXT:  error: instruction requires the following: 'C' (Compressed Instructions){{$}}
+# CHECK-NO-EXT:  error: instruction requires the following: 'C' (Compressed Instructions) or 'Zca' (part of the C extension, excluding compressed floating point loads/stores){{$}}
 c.or a2, a3
 # CHECK-ASM-AND-OBJ: c.xor a3, a4
 # CHECK-ASM: encoding: [0xb9,0x8e]
-# CHECK-NO-EXT:  error: instruction requires the following: 'C' (Compressed Instructions){{$}}
+# CHECK-NO-EXT:  error: instruction requires the following: 'C' (Compressed Instructions) or 'Zca' (part of the C extension, excluding compressed floating point loads/stores){{$}}
 c.xor a3, a4
 # CHECK-ASM-AND-OBJ: c.sub a4, a5
 # CHECK-ASM: encoding: [0x1d,0x8f]
-# CHECK-NO-EXT:  error: instruction requires the following: 'C' (Compressed Instructions){{$}}
+# CHECK-NO-EXT:  error: instruction requires the following: 'C' (Compressed Instructions) or 'Zca' (part of the C extension, excluding compressed floating point loads/stores){{$}}
 c.sub a4, a5
 # CHECK-ASM-AND-OBJ: c.nop
 # CHECK-ASM: encoding: [0x01,0x00]
-# CHECK-NO-EXT:  error: instruction requires the following: 'C' (Compressed Instructions){{$}}
+# CHECK-NO-EXT:  error: instruction requires the following: 'C' (Compressed Instructions) or 'Zca' (part of the C extension, excluding compressed floating point loads/stores){{$}}
 c.nop
 # CHECK-ASM-AND-OBJ: c.ebreak
 # CHECK-ASM: encoding: [0x02,0x90]
-# CHECK-NO-EXT:  error: instruction requires the following: 'C' (Compressed Instructions){{$}}
+# CHECK-NO-EXT:  error: instruction requires the following: 'C' (Compressed Instructions) or 'Zca' (part of the C extension, excluding compressed floating point loads/stores){{$}}
 c.ebreak
 # CHECK-ASM-AND-OBJ: c.lui s0, 1
 # CHECK-ASM: encoding: [0x05,0x64]
-# CHECK-NO-EXT:  error: instruction requires the following: 'C' (Compressed Instructions){{$}}
+# CHECK-NO-EXT:  error: instruction requires the following: 'C' (Compressed Instructions) or 'Zca' (part of the C extension, excluding compressed floating point loads/stores){{$}}
 c.lui s0, 1
 # CHECK-ASM-AND-OBJ: c.lui s0, 31
 # CHECK-ASM: encoding: [0x7d,0x64]
-# CHECK-NO-EXT:  error: instruction requires the following: 'C' (Compressed Instructions){{$}}
+# CHECK-NO-EXT:  error: instruction requires the following: 'C' (Compressed Instructions) or 'Zca' (part of the C extension, excluding compressed floating point loads/stores){{$}}
 c.lui s0, 31
 # CHECK-ASM-AND-OBJ: c.lui s0, 1048544
 # CHECK-ASM: encoding: [0x01,0x74]
-# CHECK-NO-EXT:  error: instruction requires the following: 'C' (Compressed Instructions){{$}}
+# CHECK-NO-EXT:  error: instruction requires the following: 'C' (Compressed Instructions) or 'Zca' (part of the C extension, excluding compressed floating point loads/stores){{$}}
 c.lui s0, 0xfffe0
 # CHECK-ASM-AND-OBJ: c.lui s0, 1048575
 # CHECK-ASM: encoding: [0x7d,0x74]
-# CHECK-NO-EXT:  error: instruction requires the following: 'C' (Compressed Instructions){{$}}
+# CHECK-NO-EXT:  error: instruction requires the following: 'C' (Compressed Instructions) or 'Zca' (part of the C extension, excluding compressed floating point loads/stores){{$}}
 c.lui s0, 0xfffff
 # CHECK-ASM-AND-OBJ: c.unimp
 # CHECK-ASM: encoding: [0x00,0x00]
-# CHECK-NO-EXT:  error: instruction requires the following: 'C' (Compressed Instructions){{$}}
+# CHECK-NO-EXT:  error: instruction requires the following: 'C' (Compressed Instructions) or 'Zca' (part of the C extension, excluding compressed floating point loads/stores){{$}}
 c.unimp
diff --git a/llvm/test/MC/RISCV/rv64c-hints-valid.s b/llvm/test/MC/RISCV/rv64c-hints-valid.s
--- a/llvm/test/MC/RISCV/rv64c-hints-valid.s
+++ b/llvm/test/MC/RISCV/rv64c-hints-valid.s
@@ -3,6 +3,11 @@
 # RUN: llvm-mc -filetype=obj -triple=riscv64 -mattr=+c < %s \
 # RUN:     | llvm-objdump -M no-aliases -d -r - \
 # RUN:     | FileCheck --check-prefix=CHECK-ASM-AND-OBJ %s
+# RUN: llvm-mc %s -triple riscv64 -mattr=+experimental-zca -riscv-no-aliases -show-encoding \
+# RUN:     | FileCheck -check-prefixes=CHECK-ASM,CHECK-ASM-AND-OBJ %s
+# RUN: llvm-mc -filetype=obj -triple=riscv64 -mattr=+experimental-zca < %s \
+# RUN:     | llvm-objdump --mattr=+experimental-zca -M no-aliases -d -r - \
+# RUN:     | FileCheck --check-prefix=CHECK-ASM-AND-OBJ %s
 
 # CHECK-ASM-AND-OBJ: c.slli zero, 63
 # CHECK-ASM: encoding: [0x7e,0x10]
diff --git a/llvm/test/MC/RISCV/rv64c-invalid.s b/llvm/test/MC/RISCV/rv64c-invalid.s
--- a/llvm/test/MC/RISCV/rv64c-invalid.s
+++ b/llvm/test/MC/RISCV/rv64c-invalid.s
@@ -1,4 +1,5 @@
 # RUN: not llvm-mc -triple=riscv64 -mattr=+c < %s 2>&1 | FileCheck %s
+# RUN: not llvm-mc -triple=riscv64 -mattr=+experimental-zca < %s 2>&1 | FileCheck %s
 
 ## GPRC
 c.ld ra, 4(sp) # CHECK: :[[@LINE]]:6: error: invalid operand for instruction
diff --git a/llvm/test/MC/RISCV/rv64c-valid.s b/llvm/test/MC/RISCV/rv64c-valid.s
--- a/llvm/test/MC/RISCV/rv64c-valid.s
+++ b/llvm/test/MC/RISCV/rv64c-valid.s
@@ -3,6 +3,11 @@
 # RUN: llvm-mc -filetype=obj -triple=riscv64 -mattr=+c < %s \
 # RUN:     | llvm-objdump --mattr=+c -M no-aliases -d -r - \
 # RUN:     | FileCheck --check-prefix=CHECK-ASM-AND-OBJ %s
+# RUN: llvm-mc %s -triple=riscv64 -mattr=+experimental-zca -riscv-no-aliases -show-encoding \
+# RUN:     | FileCheck -check-prefixes=CHECK-ASM,CHECK-ASM-AND-OBJ %s
+# RUN: llvm-mc -filetype=obj -triple=riscv64 -mattr=+c < %s \
+# RUN:     | llvm-objdump --mattr=+c -M no-aliases -d -r - \
+# RUN:     | FileCheck --check-prefix=CHECK-ASM-AND-OBJ %s
 #
 #
 # RUN: not llvm-mc -triple riscv64 \
@@ -16,56 +21,56 @@
 
 # CHECK-ASM-AND-OBJ: c.ldsp ra, 0(sp)
 # CHECK-ASM: encoding: [0x82,0x60]
-# CHECK-NO-EXT:  error: instruction requires the following: 'C' (Compressed Instructions){{$}}
+# CHECK-NO-EXT:  error: instruction requires the following: 'C' (Compressed Instructions) or 'Zca' (part of the C extension, excluding compressed floating point loads/stores){{$}}
 # CHECK-NO-RV64:  error: instruction requires the following: RV64I Base Instruction Set{{$}}
 c.ldsp ra, 0(sp)
 # CHECK-ASM-AND-OBJ: c.sdsp ra, 504(sp)
 # CHECK-ASM: encoding: [0x86,0xff]
-# CHECK-NO-EXT:  error: instruction requires the following: 'C' (Compressed Instructions){{$}}
+# CHECK-NO-EXT:  error: instruction requires the following: 'C' (Compressed Instructions) or 'Zca' (part of the C extension, excluding compressed floating point loads/stores){{$}}
 # CHECK-NO-RV64:  error: instruction requires the following: RV64I Base Instruction Set{{$}}
 c.sdsp ra, 504(sp)
 # CHECK-ASM-AND-OBJ: c.ld a4, 0(a3)
 # CHECK-ASM: encoding: [0x98,0x62]
-# CHECK-NO-EXT:  error: instruction requires the following: 'C' (Compressed Instructions){{$}}
+# CHECK-NO-EXT:  error: instruction requires the following: 'C' (Compressed Instructions) or 'Zca' (part of the C extension, excluding compressed floating point loads/stores){{$}}
 # CHECK-NO-RV64:  error: instruction requires the following: RV64I Base Instruction Set{{$}}
 c.ld a4, 0(a3)
 # CHECK-ASM-AND-OBJ: c.sd a5, 248(a3)
 # CHECK-ASM: encoding: [0xfc,0xfe]
-# CHECK-NO-EXT:  error: instruction requires the following: 'C' (Compressed Instructions){{$}}
+# CHECK-NO-EXT:  error: instruction requires the following: 'C' (Compressed Instructions) or 'Zca' (part of the C extension, excluding compressed floating point loads/stores){{$}}
 # CHECK-NO-RV64:  error: instruction requires the following: RV64I Base Instruction Set{{$}}
 c.sd a5, 248(a3)
 
 # CHECK-ASM-AND-OBJ: c.subw a3, a4
 # CHECK-ASM: encoding: [0x99,0x9e]
-# CHECK-NO-EXT:  error: instruction requires the following: 'C' (Compressed Instructions){{$}}
+# CHECK-NO-EXT:  error: instruction requires the following: 'C' (Compressed Instructions) or 'Zca' (part of the C extension, excluding compressed floating point loads/stores){{$}}
 # CHECK-NO-RV64:  error: instruction requires the following: RV64I Base Instruction Set{{$}}
 c.subw a3, a4
 # CHECK-ASM-AND-OBJ: c.addw a0, a2
 # CHECK-ASM: encoding: [0x31,0x9d]
-# CHECK-NO-EXT:  error: instruction requires the following: 'C' (Compressed Instructions){{$}}
+# CHECK-NO-EXT:  error: instruction requires the following: 'C' (Compressed Instructions) or 'Zca' (part of the C extension, excluding compressed floating point loads/stores){{$}}
 # CHECK-NO-RV64:  error: instruction requires the following: RV64I Base Instruction Set{{$}}
 c.addw a0, a2
 
 # CHECK-ASM-AND-OBJ: c.addiw a3, -32
 # CHECK-ASM: encoding: [0x81,0x36]
-# CHECK-NO-EXT:  error: instruction requires the following: 'C' (Compressed Instructions){{$}}
+# CHECK-NO-EXT:  error: instruction requires the following: 'C' (Compressed Instructions) or 'Zca' (part of the C extension, excluding compressed floating point loads/stores){{$}}
 # CHECK-NO-RV64:  error: instruction requires the following: RV64I Base Instruction Set{{$}}
 c.addiw a3, -32
 # CHECK-ASM-AND-OBJ: c.addiw a3, 31
 # CHECK-ASM: encoding: [0xfd,0x26]
-# CHECK-NO-EXT:  error: instruction requires the following: 'C' (Compressed Instructions){{$}}
+# CHECK-NO-EXT:  error: instruction requires the following: 'C' (Compressed Instructions) or 'Zca' (part of the C extension, excluding compressed floating point loads/stores){{$}}
 # CHECK-NO-RV64:  error: instruction requires the following: RV64I Base Instruction Set{{$}}
 c.addiw a3, 31
 
 # CHECK-ASM-AND-OBJ: c.slli s0, 63
 # CHECK-ASM: encoding: [0x7e,0x14]
-# CHECK-NO-EXT:  error: instruction requires the following: 'C' (Compressed Instructions){{$}}
+# CHECK-NO-EXT:  error: instruction requires the following: 'C' (Compressed Instructions) or 'Zca' (part of the C extension, excluding compressed floating point loads/stores){{$}}
 c.slli s0, 63
 # CHECK-ASM-AND-OBJ: c.srli a3, 63
 # CHECK-ASM: encoding: [0xfd,0x92]
-# CHECK-NO-EXT:  error: instruction requires the following: 'C' (Compressed Instructions){{$}}
+# CHECK-NO-EXT:  error: instruction requires the following: 'C' (Compressed Instructions) or 'Zca' (part of the C extension, excluding compressed floating point loads/stores){{$}}
 c.srli a3, 63
 # CHECK-ASM-AND-OBJ: c.srai a2, 63
 # CHECK-ASM: encoding: [0x7d,0x96]
-# CHECK-NO-EXT:  error: instruction requires the following: 'C' (Compressed Instructions){{$}}
+# CHECK-NO-EXT:  error: instruction requires the following: 'C' (Compressed Instructions) or 'Zca' (part of the C extension, excluding compressed floating point loads/stores){{$}}
 c.srai a2, 63