Index: lib/Support/Host.cpp
===================================================================
--- lib/Support/Host.cpp
+++ lib/Support/Host.cpp
@@ -1486,7 +1486,9 @@
 #endif
 
 std::string sys::getProcessTriple() {
-  Triple PT(Triple::normalize(LLVM_HOST_TRIPLE));
+  std::string TargetTripleString(LLVM_HOST_TRIPLE);
+  updateTripleOSVersion(TargetTripleString);
+  Triple PT(Triple::normalize(TargetTripleString));
 
   if (sizeof(void *) == 8 && PT.isArch32Bit())
     PT = PT.get64BitArchVariant();
Index: lib/Support/Unix/Host.inc
===================================================================
--- lib/Support/Unix/Host.inc
+++ lib/Support/Unix/Host.inc
@@ -34,18 +34,30 @@
   return info.release;
 }
 
-std::string sys::getDefaultTargetTriple() {
-  std::string TargetTripleString(LLVM_DEFAULT_TARGET_TRIPLE);
-
-  // On darwin, we want to update the version to match that of the
-  // target.
+static void updateTripleOSVersion(std::string &TargetTripleString) {
+  // On darwin, we want to update the version to match that of the target.
   std::string::size_type DarwinDashIdx = TargetTripleString.find("-darwin");
   if (DarwinDashIdx != std::string::npos) {
     TargetTripleString.resize(DarwinDashIdx + strlen("-darwin"));
     TargetTripleString += getOSVersion();
+    return;
+  }
+  std::string::size_type MacOSDashIdx = TargetTripleString.find("-macos");
+  if (MacOSDashIdx != std::string::npos) {
+    TargetTripleString.resize(MacOSDashIdx);
+    // Reset the OS to darwin as the OS version from `uname` doesn't use the
+    // macOS version scheme.
+    TargetTripleString += "-darwin";
+    TargetTripleString += getOSVersion();
   }
+}
+
+std::string sys::getDefaultTargetTriple() {
+  std::string TargetTripleString(LLVM_DEFAULT_TARGET_TRIPLE);
+  updateTripleOSVersion(TargetTripleString);
 
-  // Override the default target with an environment variable named by LLVM_TARGET_TRIPLE_ENV.
+  // Override the default target with an environment variable named by
+  // LLVM_TARGET_TRIPLE_ENV.
 #if defined(LLVM_TARGET_TRIPLE_ENV)
   if (const char *EnvTriple = std::getenv(LLVM_TARGET_TRIPLE_ENV))
     TargetTripleString = EnvTriple;
Index: lib/Support/Windows/Host.inc
===================================================================
--- lib/Support/Windows/Host.inc
+++ lib/Support/Windows/Host.inc
@@ -17,6 +17,10 @@
 
 using namespace llvm;
 
+static void updateTripleOSVersion(std::string &) {
+  // Do nothing.
+}
+
 std::string sys::getDefaultTargetTriple() {
   const char *Triple = LLVM_DEFAULT_TARGET_TRIPLE;