diff --git a/clang/include/clang/Basic/LangStandard.h b/clang/include/clang/Basic/LangStandard.h
index 5cc1c7e0e397175a304329c9064ae03e9c75341a..6b15386e334eb936c016be54585e1cf8889929a9 100644
--- a/clang/include/clang/Basic/LangStandard.h
+++ b/clang/include/clang/Basic/LangStandard.h
@@ -41,9 +41,9 @@ enum class Language : uint8_t {
   RenderScript,
   HIP,
   HLSL,
-  #if ENABLE_BSC
+#if ENABLE_BSC
   BSC,
-  #endif
+#endif
   ///@}
 };
 
@@ -64,10 +64,6 @@ enum LangFeatures {
   HexFloat = (1 << 13),
   OpenCL = (1 << 14),
   HLSL = (1 << 15)
-#if ENABLE_BSC
-      ,
-  BSC = (1 << 16)
-#endif
 };
 
 /// LangStandard - Information about the properties of a particular language
@@ -140,11 +136,6 @@ public:
   /// isOpenCL - Language is a OpenCL variant.
   bool isOpenCL() const { return Flags & OpenCL; }
 
-  #if ENABLE_BSC
-  /// isBSC - Language is a BiSheng C variant.
-  bool isBSC() const { return Flags & BSC; }
-  #endif
-
   static Kind getLangKind(StringRef Name);
   static const LangStandard &getLangStandardForKind(Kind K);
   static const LangStandard *getLangStandardForName(StringRef Name);
diff --git a/clang/include/clang/Basic/LangStandards.def b/clang/include/clang/Basic/LangStandards.def
index f6d8a4afe8d4a85c6c83747e924aa03a4e6c8661..323032f41da02ef1d1bf531b7809f13f85835865 100644
--- a/clang/include/clang/Basic/LangStandards.def
+++ b/clang/include/clang/Basic/LangStandards.def
@@ -213,11 +213,6 @@ LANGSTANDARD(hlsl, "hlsl",
              HLSL, "High Level Shader Language",
              LineComment | HLSL | CPlusPlus )
 
-#if ENABLE_BSC
-LANGSTANDARD(bsc, "bsc", BSC, "BiSheng C Language",
-             LineComment | BSC | C99 | C11 | C17 | Digraphs | GNUMode | HexFloat)
-#endif
-
 LANGSTANDARD(hlsl2015, "hlsl2015",
              HLSL, "High Level Shader Language 2015",
              LineComment | HLSL | CPlusPlus )
diff --git a/clang/lib/Basic/LangOptions.cpp b/clang/lib/Basic/LangOptions.cpp
index a9346457c4719842c9d7be1a5b7947b506726bb4..e757a70909cb4299826c47a324358bb5c88e9266 100644
--- a/clang/lib/Basic/LangOptions.cpp
+++ b/clang/lib/Basic/LangOptions.cpp
@@ -94,6 +94,11 @@ void LangOptions::setLangDefaults(LangOptions &Opts, Language Lang,
   } else if (Lang == Language::ObjC || Lang == Language::ObjCXX) {
     Opts.ObjC = 1;
   }
+#if ENABLE_BSC
+  else if (Lang == Language::BSC) {
+    Opts.BSC = 1;
+  }
+#endif
 
   if (LangStd == LangStandard::lang_unspecified)
     LangStd = getDefaultLanguageStandard(Lang, T);
@@ -104,9 +109,6 @@ void LangOptions::setLangDefaults(LangOptions &Opts, Language Lang,
   Opts.C11 = Std.isC11();
   Opts.C17 = Std.isC17();
   Opts.C2x = Std.isC2x();
-  #if ENABLE_BSC
-  Opts.BSC = Std.isBSC();
-  #endif
   Opts.CPlusPlus = Std.isCPlusPlus();
   Opts.CPlusPlus11 = Std.isCPlusPlus11();
   Opts.CPlusPlus14 = Std.isCPlusPlus14();
diff --git a/clang/lib/Basic/LangStandards.cpp b/clang/lib/Basic/LangStandards.cpp
index 511bb953faaa9d82e8919341f1b1c46b3c44c1cc..d42be1205f1a635848f1070ecb070c1803c7aaa3 100644
--- a/clang/lib/Basic/LangStandards.cpp
+++ b/clang/lib/Basic/LangStandards.cpp
@@ -85,10 +85,13 @@ LangStandard::Kind clang::getDefaultLanguageStandard(clang::Language Lang,
     return LangStandard::lang_hip;
   case Language::HLSL:
     return LangStandard::lang_hlsl2021;
-  #if ENABLE_BSC
+#if ENABLE_BSC
   case Language::BSC:
-    return LangStandard::lang_bsc;
-  #endif
+    if (CLANG_DEFAULT_STD_C != LangStandard::lang_unspecified)
+      return CLANG_DEFAULT_STD_C;
+
+    return LangStandard::lang_gnu11;
+#endif
   }
   llvm_unreachable("unhandled Language kind!");
 }
diff --git a/clang/lib/Frontend/CompilerInvocation.cpp b/clang/lib/Frontend/CompilerInvocation.cpp
index 55b0018cacbe5d2a0d6de2b29e6087fcc4b47271..bdc8d1720df438f2b0de1dc7b2d3a97dc3985c1b 100644
--- a/clang/lib/Frontend/CompilerInvocation.cpp
+++ b/clang/lib/Frontend/CompilerInvocation.cpp
@@ -3248,6 +3248,9 @@ static bool IsInputCompatibleWithStandard(InputKind IK,
   case Language::C:
   case Language::ObjC:
   case Language::RenderScript:
+#if ENABLE_BSC
+  case Language::BSC:
+#endif
     return S.getLanguage() == Language::C;
 
   case Language::OpenCL:
@@ -3269,11 +3272,6 @@ static bool IsInputCompatibleWithStandard(InputKind IK,
   case Language::HIP:
     return S.getLanguage() == Language::CXX || S.getLanguage() == Language::HIP;
 
-  #if ENABLE_BSC
-  case Language::BSC:
-    return S.getLanguage() == Language::C || S.getLanguage() == Language::BSC;
-  #endif
-
   case Language::Asm:
     // Accept (and ignore) all -std= values.
     // FIXME: The -std= value is not ignored; it affects the tokenization
diff --git a/clang/test/BSC/Negative/Driver/options/std_option/std_option.cbs b/clang/test/BSC/Negative/Driver/options/std_option/std_option.cbs
index d60bdae7ad7defa01022c741e6e39ec889f7ad1e..35931ad3e824a40c3565673aeb51d825f31f8e44 100644
--- a/clang/test/BSC/Negative/Driver/options/std_option/std_option.cbs
+++ b/clang/test/BSC/Negative/Driver/options/std_option/std_option.cbs
@@ -1,12 +1,10 @@
-// RUN: %clang_cc1 -std=c11 -verify %s
-// RUN: %clang_cc1 -std=c89 -verify %s
-// RUN: %clang_cc1 -std=c99 -verify %s
-// RUN: %clang_cc1 -std=c17 -verify %s
+// RUN: not %clang_cc1 -x bsc -std=c++11 -verify %s \
+// RUN: 2>&1 | FileCheck %s -check-prefix=CHECK-INVALID-OPTION
+
+// CHECK-INVALID-OPTION: (frontend): invalid argument '-std=c++11' not allowed with 'BSC'
 
 struct Foo {
 };
-// expected-error@+2 {{cannot combine with previous 'int' declaration specifier}}
-// expected-error@+1 {{expected identifier or '('}}
 int struct Foo::getA(struct Foo* this) { 
     return 1;
 }
diff --git a/clang/test/BSC/Positive/Driver/options/std_option/std_option.cbs b/clang/test/BSC/Positive/Driver/options/std_option/std_option.cbs
new file mode 100644
index 0000000000000000000000000000000000000000..bd7df7e2bae5a7a25cbf57f76e173ef99add0aa8
--- /dev/null
+++ b/clang/test/BSC/Positive/Driver/options/std_option/std_option.cbs
@@ -0,0 +1,17 @@
+// RUN: %clang_cc1 -std=c11 -verify %s
+// RUN: %clang_cc1 -std=c89 -verify %s
+// RUN: %clang_cc1 -std=c99 -verify %s
+// RUN: %clang_cc1 -std=c17 -verify %s
+// RUN: %clang_cc1 -std=gnu11 -verify %s
+// RUN: %clang_cc1 -x bsc -std=c11 -verify %s
+// RUN: %clang_cc1 -x bsc -std=c89 -verify %s
+// RUN: %clang_cc1 -x bsc -std=c99 -verify %s
+// RUN: %clang_cc1 -x bsc -std=c17 -verify %s
+// RUN: %clang_cc1 -x bsc -std=gnu11 -verify %s
+// expected-no-diagnostics
+
+struct Foo {
+};
+int struct Foo::getA(struct Foo* this) { 
+    return 1;
+}