Index: clang/include/clang/Lex/Preprocessor.h
===================================================================
--- clang/include/clang/Lex/Preprocessor.h
+++ clang/include/clang/Lex/Preprocessor.h
@@ -178,6 +178,8 @@
   IdentifierInfo *Ident__is_target_vendor;         // __is_target_vendor
   IdentifierInfo *Ident__is_target_os;             // __is_target_os
   IdentifierInfo *Ident__is_target_environment;    // __is_target_environment
+  IdentifierInfo *Ident__is_target_variant_os;
+  IdentifierInfo *Ident__is_target_variant_environment;
   IdentifierInfo *Ident__FLT_EVAL_METHOD__;        // __FLT_EVAL_METHOD
 
   // Weak, only valid (and set) while InMacroArgs is true.
Index: clang/lib/Lex/PPMacroExpansion.cpp
===================================================================
--- clang/lib/Lex/PPMacroExpansion.cpp
+++ clang/lib/Lex/PPMacroExpansion.cpp
@@ -387,6 +387,10 @@
   Ident__is_target_os     = RegisterBuiltinMacro(*this, "__is_target_os");
   Ident__is_target_environment =
       RegisterBuiltinMacro(*this, "__is_target_environment");
+  Ident__is_target_variant_os =
+      RegisterBuiltinMacro(*this, "__is_target_variant_os");
+  Ident__is_target_variant_environment =
+      RegisterBuiltinMacro(*this, "__is_target_variant_environment");
 
   // Modules.
   Ident__building_module  = RegisterBuiltinMacro(*this, "__building_module");
@@ -1431,6 +1435,39 @@
   return TI.getTriple().getEnvironment() == Env.getEnvironment();
 }
 
+/// Implements the __is_target_variant_os builtin macro.
+static bool isTargetVariantOS(const TargetInfo &TI, const IdentifierInfo *II) {
+  if (TI.getTriple().isOSDarwin()) {
+    const llvm::Triple *VariantTriple = TI.getDarwinTargetVariantTriple();
+    if (!VariantTriple)
+      return false;
+
+    std::string OSName =
+        (llvm::Twine("unknown-unknown-") + II->getName().lower()).str();
+    llvm::Triple OS(OSName);
+    if (OS.getOS() == llvm::Triple::Darwin) {
+      // Darwin matches macos, ios, etc.
+      return VariantTriple->isOSDarwin();
+    }
+    return VariantTriple->getOS() == OS.getOS();
+  }
+  return false;
+}
+
+/// Implements the __is_target_variant_environment builtin macro.
+static bool isTargetVariantEnvironment(const TargetInfo &TI,
+                                const IdentifierInfo *II) {
+  if (TI.getTriple().isOSDarwin()) {
+    const llvm::Triple *VariantTriple = TI.getDarwinTargetVariantTriple();
+    if (!VariantTriple)
+      return false;
+    std::string EnvName = (llvm::Twine("---") + II->getName().lower()).str();
+    llvm::Triple Env(EnvName);
+    return VariantTriple->getEnvironment() == Env.getEnvironment();
+  }
+  return false;
+}
+
 /// ExpandBuiltinMacro - If an identifier token is read that is to be expanded
 /// as a builtin macro, handle it and return the next token as 'Tok'.
 void Preprocessor::ExpandBuiltinMacro(Token &Tok) {
@@ -1678,6 +1715,8 @@
               .Case("__is_target_vendor", true)
               .Case("__is_target_os", true)
               .Case("__is_target_environment", true)
+              .Case("__is_target_variant_os", true)
+              .Case("__is_target_variant_environment", true)
               .Default(false);
         }
       });
@@ -1878,6 +1917,22 @@
               Tok, *this, diag::err_feature_check_malformed);
           return II && isTargetEnvironment(getTargetInfo(), II);
         });
+  } else if (II == Ident__is_target_variant_os) {
+    EvaluateFeatureLikeBuiltinMacro(
+        OS, Tok, II, *this, false,
+        [this](Token &Tok, bool &HasLexedNextToken) -> int {
+          IdentifierInfo *II = ExpectFeatureIdentifierInfo(
+              Tok, *this, diag::err_feature_check_malformed);
+          return II && isTargetVariantOS(getTargetInfo(), II);
+        });
+  } else if (II == Ident__is_target_variant_environment) {
+    EvaluateFeatureLikeBuiltinMacro(
+        OS, Tok, II, *this, false,
+        [this](Token &Tok, bool &HasLexedNextToken) -> int {
+          IdentifierInfo *II = ExpectFeatureIdentifierInfo(
+              Tok, *this, diag::err_feature_check_malformed);
+          return II && isTargetVariantEnvironment(getTargetInfo(), II);
+        });
   } else {
     llvm_unreachable("Unknown identifier!");
   }
Index: clang/test/Preprocessor/is_target_unknown.c
===================================================================
--- clang/test/Preprocessor/is_target_unknown.c
+++ clang/test/Preprocessor/is_target_unknown.c
@@ -20,3 +20,13 @@
 #if !__is_target_environment(unknown)
   #error "mismatching environment"
 #endif
+
+// Unknown variant OS is not allowed.
+#if __is_target_variant_os(unknown)
+  #error "mismatching OS"
+#endif
+
+// Unknown variant environment is not allowed.
+#if __is_target_variant_environment(unknown)
+  #error "mismatching environment"
+#endif
Index: clang/test/Preprocessor/is_target_variant.c
===================================================================
--- /dev/null
+++ clang/test/Preprocessor/is_target_variant.c
@@ -0,0 +1,72 @@
+// RUN: %clang_cc1 -fsyntax-only -triple arm64-apple-macos -DMAC -verify %s
+// RUN: %clang_cc1 -fsyntax-only -triple arm64-apple-ios13.1 -DIOS -verify %s
+// RUN: %clang_cc1 -fsyntax-only -triple arm64-apple-ios13.1-macabi -DCATALYST -verify %s
+// RUN: %clang_cc1 -fsyntax-only -triple arm64-apple-macos12 -darwin-target-variant-triple arm64-apple-ios-macabi -DZIPPERED -verify %s
+// expected-no-diagnostics
+
+#if !__has_builtin(__is_target_variant_os) || !__has_builtin(__is_target_variant_environment)
+  #error "has builtin doesn't work"
+#endif
+
+#ifdef ZIPPERED
+
+  // Target variant is a darwin.
+  #if !__is_target_variant_os(darwin)
+    #error "mismatching variant os"
+  #endif
+
+  // Target variant is not macOS...
+  #if __is_target_variant_os(macos)
+    #error "mismatching variant os"
+  #endif
+
+  // ...but iOS.
+  #if !__is_target_variant_os(ios)
+    #error "mismatching variant os"
+  #endif
+
+  // Zippered builds also set the target variant environment to macabi.
+  // At the moment, only zippered builds set __is_target_variant_os(ios),
+  // so checking __is_target_variant_environment() is currently redundant
+  // with checking the former.
+  #if !__is_target_variant_environment(macabi)
+    #error "mismatching variant environment"
+  #endif
+
+#else
+
+  // In non-zippered builds, even for catalyst, no target variant is set.
+  // So these are all false.
+
+  #if __is_target_variant_os(darwin)
+    #error "mismatching variant os"
+  #endif
+
+  #if __is_target_variant_os(macos)
+    #error "mismatching variant os"
+  #endif
+
+  #if __is_target_variant_os(ios)
+    #error "mismatching variant os"
+  #endif
+
+  #if __is_target_variant_environment(macabi)
+    #error "mismatching variant environment"
+  #endif
+
+#endif
+
+// The target environment in zippered builds is _not_ macabi.
+// The target environment is macabi only in catalyst builds.
+#ifdef CATALYST
+  #if !__is_target_environment(macabi)
+    #error "mismatching environment"
+  #endif
+  #if !__is_target_os(ios)
+    #error "mismatching os"
+  #endif
+#else
+  #if __is_target_environment(macabi)
+    #error "mismatching environment"
+  #endif
+#endif