Index: include/llvm/ADT/Triple.h
===================================================================
--- include/llvm/ADT/Triple.h
+++ include/llvm/ADT/Triple.h
@@ -266,6 +266,15 @@
   std::string normalize() const { return normalize(Data); }
 
   /// @}
+  /// @name Canonicalization
+  /// @}
+
+  /// canonicalize - Return the canonical triple form, that is a form where
+  /// each component uses the spelling as defined by Triple rather then passed
+  /// externally.
+  std::string canonicalize() const;
+
+  /// @}
   /// @name Typed Component Access
   /// @{
 
Index: lib/Support/Triple.cpp
===================================================================
--- lib/Support/Triple.cpp
+++ lib/Support/Triple.cpp
@@ -906,6 +906,20 @@
   return Normalized;
 }
 
+std::string Triple::canonicalize() const {
+  SmallString<64> Triple;
+  Triple += getArchTypeName(Arch);
+  Triple += "-";
+  Triple += getVendorTypeName(Vendor);
+  Triple += "-";
+  Triple += getOSTypeName(OS);
+  if (Environment != Triple::UnknownEnvironment) {
+    Triple += "-";
+    Triple += getEnvironmentTypeName(Environment);
+  }
+  return Triple.str();
+}
+
 StringRef Triple::getArchName() const {
   return StringRef(Data).split('-').first;           // Isolate first component
 }
Index: unittests/ADT/TripleTest.cpp
===================================================================
--- unittests/ADT/TripleTest.cpp
+++ unittests/ADT/TripleTest.cpp
@@ -424,6 +424,24 @@
   EXPECT_EQ("arm-none--eabi", Triple::normalize("arm-none-eabi")); // arm-none-eabi
 }
 
+TEST(TripleTest, Canonicalization) {
+  Triple T;
+
+  T.setTriple(Triple::normalize("x86_64-linux-gnu"));
+  EXPECT_EQ(Triple::x86_64, T.getArch());
+  EXPECT_EQ(Triple::UnknownVendor, T.getVendor());
+  EXPECT_EQ(Triple::Linux, T.getOS());
+  EXPECT_EQ(Triple::GNU, T.getEnvironment());
+  EXPECT_EQ("x86_64-unknown-linux-gnu", T.canonicalize());
+
+  T.setTriple(Triple::normalize("i386-freebsd"));
+  EXPECT_EQ(Triple::x86, T.getArch());
+  EXPECT_EQ(Triple::UnknownVendor, T.getVendor());
+  EXPECT_EQ(Triple::FreeBSD, T.getOS());
+  EXPECT_EQ(Triple::UnknownEnvironment, T.getEnvironment());
+  EXPECT_EQ("i386-unknown-freebsd", T.canonicalize());
+}
+
 TEST(TripleTest, MutateName) {
   Triple T;
   EXPECT_EQ(Triple::UnknownArch, T.getArch());