[RISCV] Mark zacas as experimental again due to unresolved ABI issue (#…

…99898) As discussed at the last sync-up call, mark Zacas as experimental until this ABI issue is resolved <riscv-non-isa/riscv-elf-psabi-doc#444>. Don't return Zacas in getHostCPUFeatures (leaving a TODO there) as even if requesting detection of "native" features, the user likely doesn't want to automatically opt in to experimental codegen.
llvm · Jul 23, 2024 · 70e7d26 · 70e7d26
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diff --git a/clang/test/Preprocessor/riscv-target-features.c b/clang/test/Preprocessor/riscv-target-features.c
@@ -86,7 +86,6 @@
 // CHECK-NOT: __riscv_za64rs {{.*$}}
 // CHECK-NOT: __riscv_zaamo {{.*$}}
 // CHECK-NOT: __riscv_zabha {{.*$}}
-// CHECK-NOT: __riscv_zacas {{.*$}}
 // CHECK-NOT: __riscv_zalrsc {{.*$}}
 // CHECK-NOT: __riscv_zama16b {{.*$}}
 // CHECK-NOT: __riscv_zawrs {{.*$}}
@@ -182,6 +181,7 @@
 // CHECK-NOT: __riscv_sspm{{.*$}}
 // CHECK-NOT: __riscv_ssqosid{{.*$}}
 // CHECK-NOT: __riscv_supm{{.*$}}
+// CHECK-NOT: __riscv_zacas {{.*$}}
 // CHECK-NOT: __riscv_zalasr {{.*$}}
 // CHECK-NOT: __riscv_zfbfmin {{.*$}}
 // CHECK-NOT: __riscv_zicfilp {{.*$}}
@@ -747,14 +747,6 @@
 // RUN:   -o - | FileCheck --check-prefix=CHECK-ZABHA-EXT %s
 // CHECK-ZABHA-EXT: __riscv_zabha 1000000{{$}}
 
-// RUN: %clang --target=riscv32 \
-// RUN:   -march=rv32ia_zacas1p0 -E -dM %s \
-// RUN:   -o - | FileCheck --check-prefix=CHECK-ZACAS-EXT %s
-// RUN: %clang --target=riscv64 \
-// RUN:   -march=rv64ia_zacas1p0 -E -dM %s \
-// RUN:   -o - | FileCheck --check-prefix=CHECK-ZACAS-EXT %s
-// CHECK-ZACAS-EXT: __riscv_zacas 1000000{{$}}
-
 // RUN: %clang --target=riscv32 \
 // RUN:   -march=rv32i_zalrsc1p0 -E -dM %s \
 // RUN:   -o - | FileCheck --check-prefix=CHECK-ZALRSC-EXT %s
@@ -1626,6 +1618,14 @@
 // CHECK-ZVKT-EXT: __riscv_zvkt 1000000{{$}}
 
 // Experimental extensions
+// RUN: %clang --target=riscv32 -menable-experimental-extensions \
+// RUN:   -march=rv32ia_zacas1p0 -E -dM %s \
+// RUN:   -o - | FileCheck --check-prefix=CHECK-ZACAS-EXT %s
+// RUN: %clang --target=riscv64 -menable-experimental-extensions \
+// RUN:   -march=rv64ia_zacas1p0 -E -dM %s \
+// RUN:   -o - | FileCheck --check-prefix=CHECK-ZACAS-EXT %s
+// CHECK-ZACAS-EXT: __riscv_zacas 1000000{{$}}
+
 // RUN: %clang --target=riscv32 -menable-experimental-extensions \
 // RUN:   -march=rv32i_zalasr0p1 -E -dM %s \
 // RUN:   -o - | FileCheck --check-prefix=CHECK-ZALASR-EXT %s

diff --git a/llvm/docs/RISCVUsage.rst b/llvm/docs/RISCVUsage.rst
@@ -153,7 +153,6 @@ on support follow.
      ``Za64rs``        Supported (`See note <#riscv-profiles-extensions-note>`__)
      ``Zaamo``         Assembly Support
      ``Zabha``         Supported
-     ``Zacas``         Supported (`See note <#riscv-zacas-note>`__)
      ``Zalrsc``        Assembly Support
      ``Zama16b``       Supported (`See note <#riscv-profiles-extensions-note>`__)
      ``Zawrs``         Assembly Support
@@ -281,11 +280,6 @@ Supported
 ``Za128rs``, ``Za64rs``, ``Zama16b``, ``Zic64b``, ``Ziccamoa``, ``Ziccif``, ``Zicclsm``, ``Ziccrse``, ``Shcounterenvw``, ``Shgatpa``, ``Shtvala``, ``Shvsatpa``, ``Shvstvala``, ``Shvstvecd``, ``Ssccptr``, ``Sscounterenw``, ``Ssstateen``, ``Ssstrict``, ``Sstvala``, ``Sstvecd``, ``Ssu64xl``, ``Svade``, ``Svbare``
   These extensions are defined as part of the `RISC-V Profiles specification <https://github.com/riscv/riscv-profiles/releases/tag/v1.0>`__.  They do not introduce any new features themselves, but instead describe existing hardware features.
 
-  .. _riscv-zacas-note:
-
-``Zacas``
-  amocas.w will be used for i32 cmpxchg. amocas.d will be used i64 cmpxchg on RV64. The compiler will not generate amocas.d on RV32 or amocas.q on RV64 due to ABI compatibilty. These can only be used in the assembler.
-
 Experimental Extensions
 =======================
 
@@ -299,6 +293,9 @@ The primary goal of experimental support is to assist in the process of ratifica
 ``experimental-ssqosid``
   LLVM implements assembler support for the `v1.0-rc1 draft specification <https://github.com/riscv/riscv-ssqosid/releases/tag/v1.0-rc1>`_.
 
+``experimental-zacas``
+  LLVM implements the `1.0 release specification <https://github.com/riscvarchive/riscv-zacas/releases/tag/v1.0>`__. amocas.w will be used for i32 cmpxchg. amocas.d will be used i64 cmpxchg on RV64. The compiler will not generate amocas.d on RV32 or amocas.q on RV64 due to ABI compatibilty. These can only be used in the assembler. The extension will be left as experimental until `an ABI issue <https://github.com/riscv-non-isa/riscv-elf-psabi-doc/issues/444>`__ is resolved.
+
 ``experimental-zalasr``
   LLVM implements the `0.0.5 draft specification <https://github.com/mehnadnerd/riscv-zalasr>`__.
 

diff --git a/llvm/docs/ReleaseNotes.rst b/llvm/docs/ReleaseNotes.rst
@@ -185,7 +185,6 @@ Changes to the RISC-V Backend
 * Codegen support was added for the Zimop (May-Be-Operations) extension.
 * The experimental Ssnpm, Smnpm, Smmpm, Sspm, and Supm 1.0.0 Pointer Masking extensions are supported.
 * The experimental Ssqosid extension is supported.
-* Zacas is no longer experimental.
 * Added the CSR names from the Resumable Non-Maskable Interrupts (Smrnmi) extension.
 * llvm-objdump now prints disassembled opcode bytes in groups of 2 or 4 bytes to
   match GNU objdump. The bytes within the groups are in big endian order.

diff --git a/llvm/lib/Target/RISCV/RISCVFeatures.td b/llvm/lib/Target/RISCV/RISCVFeatures.td
@@ -243,8 +243,8 @@ def HasStdExtZabha : Predicate<"Subtarget->hasStdExtZabha()">,
                          "'Zabha' (Byte and Halfword Atomic Memory Operations)">;
 
 def FeatureStdExtZacas
-    : RISCVExtension<"zacas", 1, 0,
-                     "'Zacas' (Atomic Compare-And-Swap Instructions)">,
+    : RISCVExperimentalExtension<"zacas", 1, 0,
+                                 "'Zacas' (Atomic Compare-And-Swap Instructions)">,
       RISCVExtensionBitmask<0, 26>;
 def HasStdExtZacas : Predicate<"Subtarget->hasStdExtZacas()">,
                      AssemblerPredicate<(all_of FeatureStdExtZacas),

diff --git a/llvm/lib/TargetParser/Host.cpp b/llvm/lib/TargetParser/Host.cpp
@@ -2067,7 +2067,8 @@ const StringMap<bool> sys::getHostCPUFeatures() {
   Features["zvfhmin"] = ExtMask & (1ULL << 31); // RISCV_HWPROBE_EXT_ZVFHMIN
   Features["zfa"] = ExtMask & (1ULL << 32);     // RISCV_HWPROBE_EXT_ZFA
   Features["ztso"] = ExtMask & (1ULL << 33);    // RISCV_HWPROBE_EXT_ZTSO
-  Features["zacas"] = ExtMask & (1ULL << 34);   // RISCV_HWPROBE_EXT_ZACAS
+  // TODO: Re-enable zacas when it is marked non-experimental again.
+  // Features["zacas"] = ExtMask & (1ULL << 34);   // RISCV_HWPROBE_EXT_ZACAS
   Features["zicond"] = ExtMask & (1ULL << 35);  // RISCV_HWPROBE_EXT_ZICOND
   Features["zihintpause"] =
       ExtMask & (1ULL << 36); // RISCV_HWPROBE_EXT_ZIHINTPAUSE

diff --git a/llvm/test/CodeGen/RISCV/atomic-cmpxchg-branch-on-result.ll b/llvm/test/CodeGen/RISCV/atomic-cmpxchg-branch-on-result.ll
@@ -1,13 +1,13 @@
 ; NOTE: Assertions have been autogenerated by utils/update_llc_test_checks.py
 ; RUN: llc -mtriple=riscv32 -mattr=+a -verify-machineinstrs < %s \
 ; RUN:   | FileCheck -check-prefixes=NOZACAS,RV32IA %s
-; RUN: llc -mtriple=riscv32 -mattr=+a,+zacas -verify-machineinstrs < %s \
+; RUN: llc -mtriple=riscv32 -mattr=+a,+experimental-zacas -verify-machineinstrs < %s \
 ; RUN:   | FileCheck -check-prefixes=ZACAS,RV32IA-ZACAS %s
 ; RUN: llc -mtriple=riscv64 -mattr=+a -verify-machineinstrs < %s \
 ; RUN:   | FileCheck -check-prefixes=NOZACAS,RV64IA %s
-; RUN: llc -mtriple=riscv64 -mattr=+a,+zacas -verify-machineinstrs < %s \
+; RUN: llc -mtriple=riscv64 -mattr=+a,+experimental-zacas -verify-machineinstrs < %s \
 ; RUN:   | FileCheck -check-prefixes=ZACAS,RV64IA-ZACAS %s
-; RUN: llc -mtriple=riscv64 -mattr=+a,+zacas,+zabha -verify-machineinstrs < %s \
+; RUN: llc -mtriple=riscv64 -mattr=+a,+experimental-zacas,+zabha -verify-machineinstrs < %s \
 ; RUN:   | FileCheck -check-prefixes=ZACAS,RV64IA-ZABHA %s
 
 ; Test cmpxchg followed by a branch on the cmpxchg success value to see if the

diff --git a/llvm/test/CodeGen/RISCV/atomic-cmpxchg.ll b/llvm/test/CodeGen/RISCV/atomic-cmpxchg.ll
@@ -3,25 +3,25 @@
 ; RUN:   | FileCheck -check-prefix=RV32I %s
 ; RUN: llc -mtriple=riscv32 -mattr=+a -verify-machineinstrs < %s \
 ; RUN:   | FileCheck -check-prefixes=RV32IA,RV32IA-WMO %s
-; RUN: llc -mtriple=riscv32 -mattr=+a,+zacas -verify-machineinstrs < %s \
+; RUN: llc -mtriple=riscv32 -mattr=+a,+experimental-zacas -verify-machineinstrs < %s \
 ; RUN:   | FileCheck -check-prefixes=RV32IA,RV32IA-ZACAS,RV32IA-WMO-ZACAS %s
 ; RUN: llc -mtriple=riscv32 -mattr=+a,+ztso -verify-machineinstrs < %s \
 ; RUN:   | FileCheck -check-prefixes=RV32IA,RV32IA-TSO %s
-; RUN: llc -mtriple=riscv32 -mattr=+a,+ztso,+zacas -verify-machineinstrs < %s \
+; RUN: llc -mtriple=riscv32 -mattr=+a,+ztso,+experimental-zacas -verify-machineinstrs < %s \
 ; RUN:   | FileCheck -check-prefixes=RV32IA,RV32IA-ZACAS,RV32IA-TSO-ZACAS %s
 ; RUN: llc -mtriple=riscv64 -verify-machineinstrs < %s \
 ; RUN:   | FileCheck -check-prefix=RV64I %s
 ; RUN: llc -mtriple=riscv64 -mattr=+a -verify-machineinstrs < %s \
 ; RUN:   | FileCheck -check-prefixes=RV64IA,RV64IA-WMO %s
-; RUN: llc -mtriple=riscv64 -mattr=+a,+zacas -verify-machineinstrs < %s \
+; RUN: llc -mtriple=riscv64 -mattr=+a,+experimental-zacas -verify-machineinstrs < %s \
 ; RUN:   | FileCheck -check-prefixes=RV64IA,RV64IA-ZACAS,RV64IA-WMO-ZACAS %s
-; RUN: llc -mtriple=riscv64 -mattr=+a,+zacas,+zabha -verify-machineinstrs < %s \
+; RUN: llc -mtriple=riscv64 -mattr=+a,+experimental-zacas,+zabha -verify-machineinstrs < %s \
 ; RUN:   | FileCheck -check-prefixes=RV64IA,RV64IA-ZABHA,RV64IA-WMO-ZABHA %s
 ; RUN: llc -mtriple=riscv64 -mattr=+a,+ztso -verify-machineinstrs < %s \
 ; RUN:   | FileCheck -check-prefixes=RV64IA,RV64IA-TSO %s
-; RUN: llc -mtriple=riscv64 -mattr=+a,+ztso,+zacas -verify-machineinstrs < %s \
+; RUN: llc -mtriple=riscv64 -mattr=+a,+ztso,+experimental-zacas -verify-machineinstrs < %s \
 ; RUN:   | FileCheck -check-prefixes=RV64IA,RV64IA-ZACAS,RV64IA-TSO-ZACAS %s
-; RUN: llc -mtriple=riscv64 -mattr=+a,+ztso,+zacas,+zabha -verify-machineinstrs < %s \
+; RUN: llc -mtriple=riscv64 -mattr=+a,+ztso,+experimental-zacas,+zabha -verify-machineinstrs < %s \
 ; RUN:   | FileCheck -check-prefixes=RV64IA,RV64IA-ZABHA,RV64IA-TSO-ZABHA %s
 
 define void @cmpxchg_i8_monotonic_monotonic(ptr %ptr, i8 %cmp, i8 %val) nounwind {

diff --git a/llvm/test/CodeGen/RISCV/atomic-rmw.ll b/llvm/test/CodeGen/RISCV/atomic-rmw.ll
@@ -12,22 +12,22 @@
 ; RUN: llc -mtriple=riscv64 -mattr=+a,+ztso -verify-machineinstrs < %s \
 ; RUN:   | FileCheck -check-prefixes=RV64IA,RV64IA-NOZACAS,RV64IA-TSO,RV64IA-TSO-NOZACAS %s
 
-; RUN: llc -mtriple=riscv32 -mattr=+a,+zacas -verify-machineinstrs < %s \
+; RUN: llc -mtriple=riscv32 -mattr=+a,+experimental-zacas -verify-machineinstrs < %s \
 ; RUN:   | FileCheck -check-prefixes=RV32IA,RV32IA-ZACAS,RV32IA-WMO,RV32IA-WMO-ZACAS %s
-; RUN: llc -mtriple=riscv32 -mattr=+a,+ztso,+zacas -verify-machineinstrs < %s \
+; RUN: llc -mtriple=riscv32 -mattr=+a,+ztso,+experimental-zacas -verify-machineinstrs < %s \
 ; RUN:   | FileCheck -check-prefixes=RV32IA,RV32IA-ZACAS,RV32IA-TSO,RV32IA-TSO-ZACAS %s
-; RUN: llc -mtriple=riscv64 -mattr=+a,+zacas -verify-machineinstrs < %s \
+; RUN: llc -mtriple=riscv64 -mattr=+a,+experimental-zacas -verify-machineinstrs < %s \
 ; RUN:   | FileCheck -check-prefixes=RV64IA,RV64IA-ZACAS,RV64IA-WMO,RV64IA-WMO-ZACAS %s
-; RUN: llc -mtriple=riscv64 -mattr=+a,+ztso,+zacas -verify-machineinstrs < %s \
+; RUN: llc -mtriple=riscv64 -mattr=+a,+ztso,+experimental-zacas -verify-machineinstrs < %s \
 ; RUN:   | FileCheck -check-prefixes=RV64IA,RV64IA-ZACAS,RV64IA-TSO,RV64IA-TSO-ZACAS %s
 
 ; RUN: llc -mtriple=riscv64 -mattr=+a,+zabha -verify-machineinstrs < %s \
 ; RUN:   | FileCheck -check-prefixes=RV64IA,RV64IA-WMO,RV64IA-WMO-ZABHA,RV64IA-WMO-ZABHA-NOZACAS %s
 ; RUN: llc -mtriple=riscv64 -mattr=+a,+ztso,+zabha -verify-machineinstrs < %s \
 ; RUN:   | FileCheck -check-prefixes=RV64IA,RV64IA-TSO,RV64IA-TSO-ZABHA,RV64IA-TSO-ZABHA-NOZACAS %s
-; RUN: llc -mtriple=riscv64 -mattr=+a,+zabha,+zacas -verify-machineinstrs < %s \
+; RUN: llc -mtriple=riscv64 -mattr=+a,+zabha,+experimental-zacas -verify-machineinstrs < %s \
 ; RUN:   | FileCheck -check-prefixes=RV64IA,RV64IA-WMO,RV64IA-WMO-ZABHA,RV64IA-WMO-ZABHA-ZACAS %s
-; RUN: llc -mtriple=riscv64 -mattr=+a,+ztso,+zabha,+zacas -verify-machineinstrs < %s \
+; RUN: llc -mtriple=riscv64 -mattr=+a,+ztso,+zabha,+experimental-zacas -verify-machineinstrs < %s \
 ; RUN:   | FileCheck -check-prefixes=RV64IA,RV64IA-TSO,RV64IA-TSO-ZABHA,RV64IA-TSO-ZABHA-ZACAS %s
 
 define i8 @atomicrmw_xchg_i8_monotonic(ptr %a, i8 %b) nounwind {

diff --git a/llvm/test/CodeGen/RISCV/atomic-signext.ll b/llvm/test/CodeGen/RISCV/atomic-signext.ll
@@ -3,13 +3,13 @@
 ; RUN:   | FileCheck -check-prefix=RV32I %s
 ; RUN: llc -mtriple=riscv32 -mattr=+a -verify-machineinstrs < %s \
 ; RUN:   | FileCheck -check-prefixes=RV32IA,RV32IA-NOZACAS %s
-; RUN: llc -mtriple=riscv32 -mattr=+a,+zacas -verify-machineinstrs < %s \
+; RUN: llc -mtriple=riscv32 -mattr=+a,+experimental-zacas -verify-machineinstrs < %s \
 ; RUN:   | FileCheck -check-prefixes=RV32IA,RV32IA-ZACAS %s
 ; RUN: llc -mtriple=riscv64 -verify-machineinstrs < %s \
 ; RUN:   | FileCheck -check-prefix=RV64I %s
 ; RUN: llc -mtriple=riscv64 -mattr=+a -verify-machineinstrs < %s \
 ; RUN:   | FileCheck -check-prefixes=RV64IA,RV64IA-NOZACAS %s
-; RUN: llc -mtriple=riscv64 -mattr=+a,+zacas -verify-machineinstrs < %s \
+; RUN: llc -mtriple=riscv64 -mattr=+a,+experimental-zacas -verify-machineinstrs < %s \
 ; RUN:   | FileCheck -check-prefixes=RV64IA,RV64IA-ZACAS %s
 
 define signext i8 @atomic_load_i8_unordered(ptr %a) nounwind {

diff --git a/llvm/test/CodeGen/RISCV/attributes.ll b/llvm/test/CodeGen/RISCV/attributes.ll
@@ -120,7 +120,7 @@
 ; RUN: llc -mtriple=riscv32 -mattr=+zfbfmin %s -o - | FileCheck --check-prefixes=CHECK,RV32ZFBFMIN %s
 ; RUN: llc -mtriple=riscv32 -mattr=+zvfbfmin %s -o - | FileCheck --check-prefixes=CHECK,RV32ZVFBFMIN %s
 ; RUN: llc -mtriple=riscv32 -mattr=+zvfbfwma %s -o - | FileCheck --check-prefixes=CHECK,RV32ZVFBFWMA %s
-; RUN: llc -mtriple=riscv32 -mattr=+a,zacas %s -o - | FileCheck --check-prefix=RV32ZACAS %s
+; RUN: llc -mtriple=riscv32 -mattr=+a,+experimental-zacas %s -o - | FileCheck --check-prefix=RV32ZACAS %s
 ; RUN: llc -mtriple=riscv32 -mattr=+experimental-zalasr %s -o - | FileCheck --check-prefix=RV32ZALASR %s
 ; RUN: llc -mtriple=riscv32 -mattr=+zama16b %s -o - | FileCheck --check-prefixes=CHECK,RV32ZAMA16B %s
 ; RUN: llc -mtriple=riscv32 -mattr=+experimental-zicfilp %s -o - | FileCheck --check-prefix=RV32ZICFILP %s
@@ -259,7 +259,7 @@
 ; RUN: llc -mtriple=riscv64 -mattr=+zfbfmin %s -o - | FileCheck --check-prefixes=CHECK,RV64ZFBFMIN %s
 ; RUN: llc -mtriple=riscv64 -mattr=+zvfbfmin %s -o - | FileCheck --check-prefixes=CHECK,RV64ZVFBFMIN %s
 ; RUN: llc -mtriple=riscv64 -mattr=+zvfbfwma %s -o - | FileCheck --check-prefixes=CHECK,RV64ZVFBFWMA %s
-; RUN: llc -mtriple=riscv64 -mattr=+a,zacas %s -o - | FileCheck --check-prefix=RV64ZACAS %s
+; RUN: llc -mtriple=riscv64 -mattr=+a,+experimental-zacas %s -o - | FileCheck --check-prefix=RV64ZACAS %s
 ; RUN: llc -mtriple=riscv64 -mattr=+experimental-zalasr %s -o - | FileCheck --check-prefix=RV64ZALASR %s
 ; RUN: llc -mtriple=riscv64 -mattr=+experimental-zicfilp %s -o - | FileCheck --check-prefix=RV64ZICFILP %s
 ; RUN: llc -mtriple=riscv64 -mattr=+a,+zabha %s -o - | FileCheck --check-prefix=RV64ZABHA %s

diff --git a/llvm/test/MC/RISCV/rv32zacas-invalid.s b/llvm/test/MC/RISCV/rv32zacas-invalid.s
@@ -1,4 +1,4 @@
-# RUN: not llvm-mc -triple riscv32 -mattr=+a,zacas < %s 2>&1 | FileCheck %s
+# RUN: not llvm-mc -triple riscv32 -mattr=+a,+experimental-zacas < %s 2>&1 | FileCheck %s
 
 # Non-zero offsets not supported for the third operand (rs1).
 amocas.w a1, a3, 1(a5) # CHECK: :[[@LINE]]:18: error: optional integer offset must be 0

diff --git a/llvm/test/MC/RISCV/rv32zacas-valid.s b/llvm/test/MC/RISCV/rv32zacas-valid.s
@@ -1,12 +1,12 @@
-# RUN: llvm-mc %s -triple=riscv32 -mattr=+a,+zacas -riscv-no-aliases -show-encoding \
+# RUN: llvm-mc %s -triple=riscv32 -mattr=+a,+experimental-zacas -riscv-no-aliases -show-encoding \
 # RUN:     | FileCheck -check-prefixes=CHECK-ASM,CHECK-ASM-AND-OBJ %s
-# RUN: llvm-mc %s -triple=riscv64 -mattr=+a,+zacas -riscv-no-aliases -show-encoding \
+# RUN: llvm-mc %s -triple=riscv64 -mattr=+a,+experimental-zacas -riscv-no-aliases -show-encoding \
 # RUN:     | FileCheck -check-prefixes=CHECK-ASM,CHECK-ASM-AND-OBJ %s
-# RUN: llvm-mc -filetype=obj -triple=riscv32 -mattr=+a,+zacas < %s \
-# RUN:     | llvm-objdump --mattr=+a,+zacas -M no-aliases -d -r - \
+# RUN: llvm-mc -filetype=obj -triple=riscv32 -mattr=+a,+experimental-zacas < %s \
+# RUN:     | llvm-objdump --mattr=+a,+experimental-zacas -M no-aliases -d -r - \
 # RUN:     | FileCheck --check-prefix=CHECK-ASM-AND-OBJ %s
-# RUN: llvm-mc -filetype=obj -triple=riscv64 -mattr=+a,+zacas < %s \
-# RUN:     | llvm-objdump --mattr=+a,+zacas -M no-aliases -d -r - \
+# RUN: llvm-mc -filetype=obj -triple=riscv64 -mattr=+a,+experimental-zacas < %s \
+# RUN:     | llvm-objdump --mattr=+a,+experimental-zacas -M no-aliases -d -r - \
 # RUN:     | FileCheck --check-prefix=CHECK-ASM-AND-OBJ %s
 # RUN: not llvm-mc -triple=riscv32 -mattr=+a -show-encoding %s 2>&1 \
 # RUN:        | FileCheck %s --check-prefix=CHECK-ERROR

diff --git a/llvm/test/MC/RISCV/rv64zacas-invalid.s b/llvm/test/MC/RISCV/rv64zacas-invalid.s
@@ -1,4 +1,4 @@
-# RUN: not llvm-mc -triple riscv64 -mattr=+experimental-zacas < %s 2>&1 | FileCheck %s
+# RUN: not llvm-mc -triple riscv64 -mattr=+a,+experimental-zacas < %s 2>&1 | FileCheck %s
 
 # Non-zero offsets not supported for the third operand (rs1).
 amocas.w a1, a3, 1(a5) # CHECK: :[[@LINE]]:18: error: optional integer offset must be 0

diff --git a/llvm/test/MC/RISCV/rv64zacas-valid.s b/llvm/test/MC/RISCV/rv64zacas-valid.s
@@ -1,7 +1,7 @@
-# RUN: llvm-mc %s -triple=riscv64 -mattr=+a,zacas -riscv-no-aliases -show-encoding \
+# RUN: llvm-mc %s -triple=riscv64 -mattr=+a,+experimental-zacas -riscv-no-aliases -show-encoding \
 # RUN:     | FileCheck -check-prefixes=CHECK-ASM,CHECK-ASM-AND-OBJ %s
-# RUN: llvm-mc -filetype=obj -triple=riscv64 -mattr=+a,zacas < %s \
-# RUN:     | llvm-objdump --mattr=+a,zacas -M no-aliases -d -r - \
+# RUN: llvm-mc -filetype=obj -triple=riscv64 -mattr=+a,+experimental-zacas < %s \
+# RUN:     | llvm-objdump --mattr=+a,+experimental-zacas -M no-aliases -d -r - \
 # RUN:     | FileCheck --check-prefix=CHECK-ASM-AND-OBJ %s
 # RUN: not llvm-mc -triple=riscv64 -mattr=+a -show-encoding %s 2>&1 \
 # RUN:        | FileCheck %s --check-prefix=CHECK-ERROR

diff --git a/llvm/test/MC/RISCV/rvzabha-zacas-valid.s b/llvm/test/MC/RISCV/rvzabha-zacas-valid.s
@@ -1,12 +1,12 @@
-# RUN: llvm-mc %s -triple=riscv32 -mattr=+a,+zabha,+zacas -riscv-no-aliases -show-encoding \
+# RUN: llvm-mc %s -triple=riscv32 -mattr=+a,+zabha,+experimental-zacas -riscv-no-aliases -show-encoding \
 # RUN:     | FileCheck -check-prefixes=CHECK-ASM,CHECK-ASM-AND-OBJ %s
-# RUN: llvm-mc %s -triple=riscv64 -mattr=+a,+zabha,+zacas -riscv-no-aliases -show-encoding \
+# RUN: llvm-mc %s -triple=riscv64 -mattr=+a,+zabha,+experimental-zacas -riscv-no-aliases -show-encoding \
 # RUN:     | FileCheck -check-prefixes=CHECK-ASM,CHECK-ASM-AND-OBJ %s
-# RUN: llvm-mc -filetype=obj -triple=riscv32 -mattr=+a,+zabha,+zacas < %s \
-# RUN:     | llvm-objdump --mattr=+a,+zabha,+zacas -M no-aliases -d -r - \
+# RUN: llvm-mc -filetype=obj -triple=riscv32 -mattr=+a,+zabha,+experimental-zacas < %s \
+# RUN:     | llvm-objdump --mattr=+a,+zabha,+experimental-zacas -M no-aliases -d -r - \
 # RUN:     | FileCheck --check-prefix=CHECK-ASM-AND-OBJ %s
-# RUN: llvm-mc -filetype=obj -triple=riscv64 -mattr=+a,+zabha,+zacas < %s \
-# RUN:     | llvm-objdump --mattr=+a,+zabha,+zacas -M no-aliases -d -r - \
+# RUN: llvm-mc -filetype=obj -triple=riscv64 -mattr=+a,+zabha,+experimental-zacas < %s \
+# RUN:     | llvm-objdump --mattr=+a,+zabha,+experimental-zacas -M no-aliases -d -r - \
 # RUN:     | FileCheck --check-prefix=CHECK-ASM-AND-OBJ %s
 # RUN: not llvm-mc -triple=riscv32 -mattr=+a,+zabha -show-encoding %s 2>&1 \
 # RUN:        | FileCheck %s --check-prefix=CHECK-ERROR

diff --git a/llvm/unittests/TargetParser/RISCVISAInfoTest.cpp b/llvm/unittests/TargetParser/RISCVISAInfoTest.cpp
@@ -892,7 +892,6 @@ R"(All available -march extensions for RISC-V
     za64rs               1.0
     zaamo                1.0
     zabha                1.0
-    zacas                1.0
     zalrsc               1.0
     zama16b              1.0
     zawrs                1.0
@@ -1028,6 +1027,7 @@ R"(All available -march extensions for RISC-V
 Experimental extensions
     zicfilp              1.0       This is a long dummy description
     zicfiss              1.0
+    zacas                1.0
     zalasr               0.1
     smmpm                1.0
     smnpm                1.0