diff --git a/clang/include/clang/Basic/LangStandards.def b/clang/include/clang/Basic/LangStandards.def
--- a/clang/include/clang/Basic/LangStandards.def
+++ b/clang/include/clang/Basic/LangStandards.def
@@ -200,6 +200,8 @@
 LANGSTANDARD_ALIAS_DEPR(openclcpp10, "CLC++")
 LANGSTANDARD_ALIAS_DEPR(openclcpp10, "CLC++1.0")
 LANGSTANDARD_ALIAS_DEPR(openclcpp2021, "CLC++2021")
+LANGSTANDARD_ALIAS_DEPR(openclcpp2021, "clc++21")
+LANGSTANDARD_ALIAS_DEPR(openclcpp2021, "CLC++21")
 
 // CUDA
 LANGSTANDARD(cuda, "cuda", CUDA, "NVIDIA CUDA(tm)",
diff --git a/clang/include/clang/Driver/Options.td b/clang/include/clang/Driver/Options.td
--- a/clang/include/clang/Driver/Options.td
+++ b/clang/include/clang/Driver/Options.td
@@ -866,7 +866,7 @@
   MarshallingInfoFlag<LangOpts<"CLNoSignedZero">>;
 def cl_std_EQ : Joined<["-"], "cl-std=">, Group<opencl_Group>, Flags<[CC1Option]>,
   HelpText<"OpenCL language standard to compile for.">,
-  Values<"cl,CL,cl1.0,CL1.0,cl1.1,CL1.1,cl1.2,CL1.2,cl2.0,CL2.0,cl3.0,CL3.0,clc++,CLC++,clc++1.0,CLC++1.0,clc++2021,CLC++2021">;
+  Values<"cl,CL,cl1.0,CL1.0,cl1.1,CL1.1,cl1.2,CL1.2,cl2.0,CL2.0,cl3.0,CL3.0,clc++,CLC++,clc++1.0,CLC++1.0,clc++2021,CLC++2021,clc++21,CLC++21">;
 def cl_denorms_are_zero : Flag<["-"], "cl-denorms-are-zero">, Group<opencl_Group>,
   HelpText<"OpenCL only. Allow denormals to be flushed to zero.">;
 def cl_fp32_correctly_rounded_divide_sqrt : Flag<["-"], "cl-fp32-correctly-rounded-divide-sqrt">, Group<opencl_Group>, Flags<[CC1Option]>,
diff --git a/clang/lib/Frontend/CompilerInvocation.cpp b/clang/lib/Frontend/CompilerInvocation.cpp
--- a/clang/lib/Frontend/CompilerInvocation.cpp
+++ b/clang/lib/Frontend/CompilerInvocation.cpp
@@ -3616,6 +3616,7 @@
         .Cases("clc++", "CLC++", LangStandard::lang_openclcpp10)
         .Cases("clc++1.0", "CLC++1.0", LangStandard::lang_openclcpp10)
         .Cases("clc++2021", "CLC++2021", LangStandard::lang_openclcpp2021)
+        .Cases("clc++21", "CLC++21", LangStandard::lang_openclcpp2021)
         .Default(LangStandard::lang_unspecified);
 
     if (OpenCLLangStd == LangStandard::lang_unspecified) {
diff --git a/clang/test/Driver/autocomplete.c b/clang/test/Driver/autocomplete.c
--- a/clang/test/Driver/autocomplete.c
+++ b/clang/test/Driver/autocomplete.c
@@ -53,6 +53,8 @@
 // CLSTDALL-NEXT: CLC++1.0
 // CLSTDALL-NEXT: clc++2021
 // CLSTDALL-NEXT: CLC++2021
+// CLSTDALL-NEXT: clc++21
+// CLSTDALL-NEXT: CLC++21
 // RUN: %clang --autocomplete=-fno-sanitize-coverage=,f | FileCheck %s -check-prefix=FNOSANICOVER
 // FNOSANICOVER: func
 // RUN: %clang --autocomplete=-fno-sanitize-coverage= | FileCheck %s -check-prefix=FNOSANICOVERALL
diff --git a/clang/test/Frontend/stdlang.c b/clang/test/Frontend/stdlang.c
--- a/clang/test/Frontend/stdlang.c
+++ b/clang/test/Frontend/stdlang.c
@@ -9,6 +9,7 @@
 // RUN: %clang_cc1 -x cl -cl-std=clc++ -DOPENCL %s
 // RUN: %clang_cc1 -x cl -cl-std=clc++1.0 -DOPENCL %s
 // RUN: %clang_cc1 -x cl -cl-std=clc++2021 -DOPENCL %s
+// RUN: %clang_cc1 -x cl -cl-std=clc++21 -DOPENCL %s
 // RUN: %clang_cc1 -x cl -cl-std=CL -DOPENCL %s
 // RUN: %clang_cc1 -x cl -cl-std=CL1.1 -DOPENCL %s
 // RUN: %clang_cc1 -x cl -cl-std=CL1.2 -DOPENCL %s
@@ -17,6 +18,7 @@
 // RUN: %clang_cc1 -x cl -cl-std=CLC++ -DOPENCL %s
 // RUN: %clang_cc1 -x cl -cl-std=CLC++1.0 -DOPENCL %s
 // RUN: %clang_cc1 -x cl -cl-std=CLC++2021 -DOPENCL %s
+// RUN: %clang_cc1 -x cl -cl-std=CLC++21 -DOPENCL %s
 // RUN: not %clang_cc1 -x cl -std=c99 -DOPENCL %s 2>&1 | FileCheck --check-prefix=CHECK-C99 %s
 // RUN: not %clang_cc1 -x cl -cl-std=invalid -DOPENCL %s 2>&1 | FileCheck --check-prefix=CHECK-INVALID %s
 // CHECK-C99: error: invalid argument '-std=c99' not allowed with 'OpenCL'