diff --git a/include/llvm/ADT/Triple.h b/include/llvm/ADT/Triple.h
index feade6a56fb..8dca3c1cfb1 100644
--- a/include/llvm/ADT/Triple.h
+++ b/include/llvm/ADT/Triple.h
@@ -24,7 +24,7 @@ class Twine;
 
 /// Triple - Helper class for working with target triples.
 ///
-/// Target triples are strings in the format of:
+/// Target triples are strings in the canonical form:
 ///   ARCHITECTURE-VENDOR-OPERATING_SYSTEM
 /// or
 ///   ARCHITECTURE-VENDOR-OPERATING_SYSTEM-ENVIRONMENT
@@ -35,20 +35,11 @@ class Twine;
 /// from the components of the target triple to well known IDs.
 ///
 /// At its core the Triple class is designed to be a wrapper for a triple
-/// string; it does not normally change or normalize the triple string, instead
-/// it provides additional APIs to parse normalized parts out of the triple.
+/// string; the constructor does not change or normalize the triple string.
+/// Clients that need to handle the non-canonical triples that users often
+/// specify should use the normalize method.
 ///
-/// One curiosity this implies is that for some odd triples the results of,
-/// e.g., getOSName() can be very different from the result of getOS().  For
-/// example, for 'i386-mingw32', getOS() will return MinGW32, but since
-/// getOSName() is purely based on the string structure that will return the
-/// empty string.
-///
-/// Clients should generally avoid using getOSName() and related APIs unless
-/// they are familiar with the triple format (this is particularly true when
-/// rewriting a triple).
-///
-/// See autoconf/config.guess for a glimpse into what they look like in
+/// See autoconf/config.guess for a glimpse into what triples look like in
 /// practice.
 class Triple {
 public:
@@ -117,6 +108,9 @@ private:
   mutable OSType OS;
 
   bool isInitialized() const { return Arch != InvalidArch; }
+  static ArchType ParseArch(StringRef ArchName);
+  static VendorType ParseVendor(StringRef VendorName);
+  static OSType ParseOS(StringRef OSName);
   void Parse() const;
 
 public:
@@ -133,6 +127,16 @@ public:
     Data += OSStr;
   }
 
+  /// @}
+  /// @name Normalization
+  /// @{
+
+  /// normalize - Turn an arbitrary machine specification into the canonical
+  /// triple form (or something sensible that the Triple class understands if
+  /// nothing better can reasonably be done).  In particular, it handles the
+  /// common case in which otherwise valid components are in the wrong order.
+  static std::string normalize(StringRef Str);
+
   /// @}
   /// @name Typed Component Access
   /// @{
diff --git a/lib/Support/Triple.cpp b/lib/Support/Triple.cpp
index 6a70449b56d..7806aec16c6 100644
--- a/lib/Support/Triple.cpp
+++ b/lib/Support/Triple.cpp
@@ -221,63 +221,111 @@ const char *Triple::getArchNameForAssembler() {
 
 //
 
-void Triple::Parse() const {
-  assert(!isInitialized() && "Invalid parse call.");
-
-  StringRef ArchName = getArchName();
-  StringRef VendorName = getVendorName();
-  StringRef OSName = getOSName();
-
+Triple::ArchType Triple::ParseArch(StringRef ArchName) {
   if (ArchName.size() == 4 && ArchName[0] == 'i' && 
       ArchName[2] == '8' && ArchName[3] == '6' && 
       ArchName[1] - '3' < 6) // i[3-9]86
-    Arch = x86;
+    return x86;
   else if (ArchName == "amd64" || ArchName == "x86_64")
-    Arch = x86_64;
+    return x86_64;
   else if (ArchName == "bfin")
-    Arch = bfin;
+    return bfin;
   else if (ArchName == "pic16")
-    Arch = pic16;
+    return pic16;
   else if (ArchName == "powerpc")
-    Arch = ppc;
+    return ppc;
   else if ((ArchName == "powerpc64") || (ArchName == "ppu"))
-    Arch = ppc64;
+    return ppc64;
   else if (ArchName == "mblaze")
-    Arch = mblaze;
+    return mblaze;
   else if (ArchName == "arm" ||
            ArchName.startswith("armv") ||
            ArchName == "xscale")
-    Arch = arm;
+    return arm;
   else if (ArchName == "thumb" ||
            ArchName.startswith("thumbv"))
-    Arch = thumb;
+    return thumb;
   else if (ArchName.startswith("alpha"))
-    Arch = alpha;
+    return alpha;
   else if (ArchName == "spu" || ArchName == "cellspu")
-    Arch = cellspu;
+    return cellspu;
   else if (ArchName == "msp430")
-    Arch = msp430;
+    return msp430;
   else if (ArchName == "mips" || ArchName == "mipsallegrex")
-    Arch = mips;
+    return mips;
   else if (ArchName == "mipsel" || ArchName == "mipsallegrexel" ||
            ArchName == "psp")
-    Arch = mipsel;
+    return mipsel;
   else if (ArchName == "sparc")
-    Arch = sparc;
+    return sparc;
   else if (ArchName == "sparcv9")
-    Arch = sparcv9;
+    return sparcv9;
   else if (ArchName == "s390x")
-    Arch = systemz;
+    return systemz;
   else if (ArchName == "tce")
-    Arch = tce;
+    return tce;
   else if (ArchName == "xcore")
-    Arch = xcore;
+    return xcore;
   else
-    Arch = UnknownArch;
+    return UnknownArch;
+}
 
+Triple::VendorType Triple::ParseVendor(StringRef VendorName) {
+  if (VendorName == "apple")
+    return Apple;
+  else if (VendorName == "pc")
+    return PC;
+  else
+    return UnknownVendor;
+}
+
+Triple::OSType Triple::ParseOS(StringRef OSName) {
+  if (OSName.startswith("auroraux"))
+    return AuroraUX;
+  else if (OSName.startswith("cygwin"))
+    return Cygwin;
+  else if (OSName.startswith("darwin"))
+    return Darwin;
+  else if (OSName.startswith("dragonfly"))
+    return DragonFly;
+  else if (OSName.startswith("freebsd"))
+    return FreeBSD;
+  else if (OSName.startswith("linux"))
+    return Linux;
+  else if (OSName.startswith("lv2"))
+    return Lv2;
+  else if (OSName.startswith("mingw32"))
+    return MinGW32;
+  else if (OSName.startswith("mingw64"))
+    return MinGW64;
+  else if (OSName.startswith("netbsd"))
+    return NetBSD;
+  else if (OSName.startswith("openbsd"))
+    return OpenBSD;
+  else if (OSName.startswith("psp"))
+    return Psp;
+  else if (OSName.startswith("solaris"))
+    return Solaris;
+  else if (OSName.startswith("win32"))
+    return Win32;
+  else if (OSName.startswith("haiku"))
+    return Haiku;
+  else if (OSName.startswith("minix"))
+    return Minix;
+  else
+    return UnknownOS;
+}
+
+void Triple::Parse() const {
+  assert(!isInitialized() && "Invalid parse call.");
+
+  Arch = ParseArch(getArchName());
+  Vendor = ParseVendor(getVendorName());
+  OS = ParseOS(getOSName());
 
   // Handle some exceptional cases where the OS / environment components are
   // stuck into the vendor field.
+  // TODO: Remove this logic and have places that need it use 'normalize'.
   if (StringRef(getTriple()).count('-') == 1) {
     StringRef VendorName = getVendorName();
 
@@ -291,51 +339,136 @@ void Triple::Parse() const {
     // the environment.
   }
 
-  if (VendorName == "apple")
-    Vendor = Apple;
-  else if (VendorName == "pc")
-    Vendor = PC;
-  else
-    Vendor = UnknownVendor;
-
-  if (OSName.startswith("auroraux"))
-    OS = AuroraUX;
-  else if (OSName.startswith("cygwin"))
-    OS = Cygwin;
-  else if (OSName.startswith("darwin"))
-    OS = Darwin;
-  else if (OSName.startswith("dragonfly"))
-    OS = DragonFly;
-  else if (OSName.startswith("freebsd"))
-    OS = FreeBSD;
-  else if (OSName.startswith("linux"))
-    OS = Linux;
-  else if (OSName.startswith("lv2"))
-    OS = Lv2;
-  else if (OSName.startswith("mingw32"))
-    OS = MinGW32;
-  else if (OSName.startswith("mingw64"))
-    OS = MinGW64;
-  else if (OSName.startswith("netbsd"))
-    OS = NetBSD;
-  else if (OSName.startswith("openbsd"))
-    OS = OpenBSD;
-  else if (OSName.startswith("psp"))
-    OS = Psp;
-  else if (OSName.startswith("solaris"))
-    OS = Solaris;
-  else if (OSName.startswith("win32"))
-    OS = Win32;
-  else if (OSName.startswith("haiku"))
-    OS = Haiku;
-  else if (OSName.startswith("minix"))
-    OS = Minix;
-  else
-    OS = UnknownOS;
-
   assert(isInitialized() && "Failed to initialize!");
 }
 
+std::string Triple::normalize(StringRef Str) {
+  // Parse into components.
+  SmallVector<StringRef, 4> Components;
+  for (size_t First = 0, Last = 0; Last != StringRef::npos; First = Last + 1) {
+    Last = Str.find('-', First);
+    Components.push_back(Str.slice(First, Last));
+  }
+
+  // If the first component corresponds to a known architecture, preferentially
+  // use it for the architecture.  If the second component corresponds to a
+  // known vendor, preferentially use it for the vendor, etc.  This avoids silly
+  // component movement when a component parses as (eg) both a valid arch and a
+  // valid os.
+  ArchType Arch = UnknownArch;
+  if (Components.size() > 0)
+    Arch = ParseArch(Components[0]);
+  VendorType Vendor = UnknownVendor;
+  if (Components.size() > 1)
+    Vendor = ParseVendor(Components[1]);
+  OSType OS = UnknownOS;
+  if (Components.size() > 2)
+    OS = ParseOS(Components[2]);
+
+  // Note which components are already in their final position.  These will not
+  // be moved.
+  bool Found[3];
+  Found[0] = Arch != UnknownArch;
+  Found[1] = Vendor != UnknownVendor;
+  Found[2] = OS != UnknownOS;
+
+  // If they are not there already, permute the components into their canonical
+  // positions by seeing if they parse as a valid architecture, and if so moving
+  // the component to the architecture position etc.
+  for (unsigned Pos = 0; Pos != 3; ++Pos) {
+    if (Found[Pos])
+      continue; // Already in the canonical position.
+
+    for (unsigned Idx = 0; Idx != Components.size(); ++Idx) {
+      // Do not reparse any components that already matched.
+      if (Idx < 3 && Found[Idx])
+        continue;
+
+      // Does this component parse as valid for the target position?
+      bool Valid = false;
+      StringRef Comp = Components[Idx];
+      switch (Pos) {
+      default:
+        assert(false && "unexpected component type!");
+      case 0:
+        Arch = ParseArch(Comp);
+        Valid = Arch != UnknownArch;
+        break;
+      case 1:
+        Vendor = ParseVendor(Comp);
+        Valid = Vendor != UnknownVendor;
+        break;
+      case 2:
+        OS = ParseOS(Comp);
+        Valid = OS != UnknownOS;
+        break;
+      }
+      if (!Valid)
+        continue; // Nope, try the next component.
+
+      // Move the component to the target position, pushing any non-fixed
+      // components that are in the way to the right.  This tends to give
+      // good results in the common cases of a forgotten vendor component
+      // or a wrongly positioned environment.
+      if (Pos < Idx) {
+        // Insert left, pushing the existing components to the right.  For
+        // example, a-b-i386 -> i386-a-b when moving i386 to the front.
+        StringRef CurrentComponent(""); // The empty component.
+        // Replace the component we are moving with an empty component.
+        std::swap(CurrentComponent, Components[Idx]);
+        // Insert the component being moved at Pos, displacing any existing
+        // components to the right.
+        for (unsigned i = Pos; !CurrentComponent.empty(); ++i) {
+          // Skip over any fixed components.
+          while (i < 3 && Found[i]) ++i;
+          // Place the component at the new position, getting the component
+          // that was at this position - it will be moved right.
+          std::swap(CurrentComponent, Components[i]);
+        }
+      } else if (Pos > Idx) {
+        // Push right by inserting empty components until the component at Idx
+        // reaches the target position Pos.  For example, pc-a -> -pc-a when
+        // moving pc to the second position.
+        do {
+          // Insert one empty component at Idx.
+          StringRef CurrentComponent(""); // The empty component.
+          for (unsigned i = Idx; i < Components.size(); ++i) {
+            // Skip over any fixed components.
+            while (i < 3 && Found[i]) ++i;
+            // Place the component at the new position, getting the component
+            // that was at this position - it will be moved right.
+            std::swap(CurrentComponent, Components[i]);
+            // If it was placed on top of an empty component then we are done.
+            if (CurrentComponent.empty())
+              break;
+          }
+          // The last component was pushed off the end - append it.
+          if (!CurrentComponent.empty())
+            Components.push_back(CurrentComponent);
+
+          // Advance Idx to the component's new position.
+          while (++Idx < 3 && Found[Idx]) {}
+        } while (Idx < Pos); // Add more until the final position is reached.
+      }
+      assert(Pos < Components.size() && Components[Pos] == Comp &&
+             "Component moved wrong!");
+      Found[Pos] = true;
+      break;
+    }
+  }
+
+  // Special case logic goes here.  At this point Arch, Vendor and OS have the
+  // correct values for the computed components.
+
+  // Stick the corrected components back together to form the normalized string.
+  std::string Normalized;
+  for (unsigned i = 0, e = Components.size(); i != e; ++i) {
+    if (i) Normalized += '-';
+    Normalized += Components[i];
+  }
+  return Normalized;
+}
+
 StringRef Triple::getArchName() const {
   return StringRef(Data).split('-').first;           // Isolate first component
 }
diff --git a/unittests/ADT/TripleTest.cpp b/unittests/ADT/TripleTest.cpp
index 1a9e81a0df7..067f5e5116c 100644
--- a/unittests/ADT/TripleTest.cpp
+++ b/unittests/ADT/TripleTest.cpp
@@ -92,18 +92,117 @@ TEST(TripleTest, ParsedIDs) {
 
   T = Triple("huh");
   EXPECT_EQ(Triple::UnknownArch, T.getArch());
+}
 
-  // Two exceptional cases.
+static std::string Join(StringRef A, StringRef B, StringRef C) {
+  std::string Str = A; Str += '-'; Str += B; Str += '-'; Str += C;
+  return Str;
+}
 
-  T = Triple("i386-mingw32");
-  EXPECT_EQ(Triple::x86, T.getArch());
-  EXPECT_EQ(Triple::PC, T.getVendor());
-  EXPECT_EQ(Triple::MinGW32, T.getOS());
+static std::string Join(StringRef A, StringRef B, StringRef C, StringRef D) {
+  std::string Str = A; Str += '-'; Str += B; Str += '-'; Str += C; Str += '-';
+  Str += D; return Str;
+}
 
-  T = Triple("arm-elf");
-  EXPECT_EQ(Triple::arm, T.getArch());
-  EXPECT_EQ(Triple::UnknownVendor, T.getVendor());
-  EXPECT_EQ(Triple::UnknownOS, T.getOS());
+TEST(TripleTest, Normalization) {
+  EXPECT_EQ("", Triple::normalize(""));
+  EXPECT_EQ("-", Triple::normalize("-"));
+  EXPECT_EQ("--", Triple::normalize("--"));
+  EXPECT_EQ("---", Triple::normalize("---"));
+  EXPECT_EQ("----", Triple::normalize("----"));
+
+  EXPECT_EQ("a", Triple::normalize("a"));
+  EXPECT_EQ("a-b", Triple::normalize("a-b"));
+  EXPECT_EQ("a-b-c", Triple::normalize("a-b-c"));
+  EXPECT_EQ("a-b-c-d", Triple::normalize("a-b-c-d"));
+
+  EXPECT_EQ("i386-b-c", Triple::normalize("i386-b-c"));
+  EXPECT_EQ("i386-a-c", Triple::normalize("a-i386-c"));
+  EXPECT_EQ("i386-a-b", Triple::normalize("a-b-i386"));
+
+  EXPECT_EQ("a-pc-c", Triple::normalize("a-pc-c"));
+  EXPECT_EQ("-pc-b-c", Triple::normalize("pc-b-c"));
+  EXPECT_EQ("a-pc-b", Triple::normalize("a-b-pc"));
+
+  EXPECT_EQ("a-b-linux", Triple::normalize("a-b-linux"));
+  EXPECT_EQ("--linux-b-c", Triple::normalize("linux-b-c"));
+  EXPECT_EQ("a--linux-c", Triple::normalize("a-linux-c"));
+
+  EXPECT_EQ("i386-pc-a", Triple::normalize("a-pc-i386"));
+  EXPECT_EQ("i386-pc-", Triple::normalize("-pc-i386"));
+  EXPECT_EQ("-pc-linux-c", Triple::normalize("linux-pc-c"));
+  EXPECT_EQ("-pc-linux", Triple::normalize("linux-pc-"));
+
+  EXPECT_EQ("i386", Triple::normalize("i386"));
+  EXPECT_EQ("-pc", Triple::normalize("pc"));
+  EXPECT_EQ("--linux", Triple::normalize("linux"));
+
+  // Check that normalizing a permutated set of valid components returns a
+  // triple with the unpermuted components.
+  StringRef C[4];
+  C[3] = "environment";
+  for (int Arch = 1+Triple::UnknownArch; Arch < Triple::InvalidArch; ++Arch) {
+    C[0] = Triple::getArchTypeName(Triple::ArchType(Arch));
+    for (int Vendor = 1+Triple::UnknownVendor; Vendor <= Triple::PC;
+         ++Vendor) {
+      C[1] = Triple::getVendorTypeName(Triple::VendorType(Vendor));
+      for (int OS = 1+Triple::UnknownOS; OS <= Triple::Minix; ++OS) {
+        C[2] = Triple::getOSTypeName(Triple::OSType(OS));
+
+        std::string E = Join(C[0], C[1], C[2]);
+        std::string F = Join(C[0], C[1], C[2], C[3]);
+        EXPECT_EQ(E, Triple::normalize(Join(C[0], C[1], C[2])));
+        EXPECT_EQ(F, Triple::normalize(Join(C[0], C[1], C[2], C[3])));
+
+        // If a value has multiple interpretations, then the permutation
+        // test will inevitably fail.  Currently this is only the case for
+        // "psp" which parses as both an architecture and an O/S.
+        if (OS == Triple::Psp)
+          continue;
+
+        EXPECT_EQ(E, Triple::normalize(Join(C[0], C[2], C[1])));
+        EXPECT_EQ(E, Triple::normalize(Join(C[1], C[2], C[0])));
+        EXPECT_EQ(E, Triple::normalize(Join(C[1], C[0], C[2])));
+        EXPECT_EQ(E, Triple::normalize(Join(C[2], C[0], C[1])));
+        EXPECT_EQ(E, Triple::normalize(Join(C[2], C[1], C[0])));
+
+        EXPECT_EQ(F, Triple::normalize(Join(C[0], C[1], C[3], C[2])));
+        EXPECT_EQ(F, Triple::normalize(Join(C[0], C[2], C[3], C[1])));
+        EXPECT_EQ(F, Triple::normalize(Join(C[0], C[2], C[1], C[3])));
+        EXPECT_EQ(F, Triple::normalize(Join(C[0], C[3], C[1], C[2])));
+        EXPECT_EQ(F, Triple::normalize(Join(C[0], C[3], C[2], C[1])));
+        EXPECT_EQ(F, Triple::normalize(Join(C[1], C[2], C[3], C[0])));
+        EXPECT_EQ(F, Triple::normalize(Join(C[1], C[2], C[0], C[3])));
+        EXPECT_EQ(F, Triple::normalize(Join(C[1], C[3], C[0], C[2])));
+        EXPECT_EQ(F, Triple::normalize(Join(C[1], C[3], C[2], C[0])));
+        EXPECT_EQ(F, Triple::normalize(Join(C[1], C[0], C[2], C[3])));
+        EXPECT_EQ(F, Triple::normalize(Join(C[1], C[0], C[3], C[2])));
+        EXPECT_EQ(F, Triple::normalize(Join(C[2], C[3], C[0], C[1])));
+        EXPECT_EQ(F, Triple::normalize(Join(C[2], C[3], C[1], C[0])));
+        EXPECT_EQ(F, Triple::normalize(Join(C[2], C[0], C[1], C[3])));
+        EXPECT_EQ(F, Triple::normalize(Join(C[2], C[0], C[3], C[1])));
+        EXPECT_EQ(F, Triple::normalize(Join(C[2], C[1], C[3], C[0])));
+        EXPECT_EQ(F, Triple::normalize(Join(C[2], C[1], C[0], C[3])));
+        EXPECT_EQ(F, Triple::normalize(Join(C[3], C[0], C[1], C[2])));
+        EXPECT_EQ(F, Triple::normalize(Join(C[3], C[0], C[2], C[1])));
+        EXPECT_EQ(F, Triple::normalize(Join(C[3], C[1], C[2], C[0])));
+        EXPECT_EQ(F, Triple::normalize(Join(C[3], C[1], C[0], C[2])));
+        EXPECT_EQ(F, Triple::normalize(Join(C[3], C[2], C[0], C[1])));
+        EXPECT_EQ(F, Triple::normalize(Join(C[3], C[2], C[1], C[0])));
+      }
+    }
+  }
+
+  EXPECT_EQ("a-b-psp", Triple::normalize("a-b-psp"));
+  EXPECT_EQ("psp-b-c", Triple::normalize("psp-b-c"));
+
+  // Various real-world funky triples.  The value returned by GCC's config.sub
+  // is given in the comment.
+  EXPECT_EQ("i386--mingw32", Triple::normalize("i386-mingw32")); // i386-pc-mingw32
+  EXPECT_EQ("x86_64--linux-gnu", Triple::normalize("x86_64-linux-gnu")); // x86_64-pc-linux-gnu
+  EXPECT_EQ("i486--linux-gnu", Triple::normalize("i486-linux-gnu")); // i486-pc-linux-gnu
+  EXPECT_EQ("i386-redhat-linux", Triple::normalize("i386-redhat-linux")); // i386-redhat-linux-gnu
+  EXPECT_EQ("i686--linux", Triple::normalize("i686-linux")); // i686-pc-linux-gnu
 }
 
 TEST(TripleTest, MutateName) {