diff --git a/tools/llvmc/src/Base.td.in b/tools/llvmc/src/Base.td.in
index c1898a694e6..efb259fbe01 100644
--- a/tools/llvmc/src/Base.td.in
+++ b/tools/llvmc/src/Base.td.in
@@ -46,8 +46,8 @@ def OptList : OptionList<[
     (help "Choose linker (possible values: gcc, g++)")),
  (parameter_option "mtune",
     (help "Target a specific CPU type"), (forward_not_split)),
- (parameter_option "march",
-    (help "Architecture to generate code for"), (forward_not_split)),
+ (parameter_list_option "march",
+    (help "Generate code for the specified machine type")),
  (parameter_option "mcpu",
     (help "A deprecated synonym for -mtune"), (hidden), (forward_not_split)),
  (switch_option "mfix-and-continue",
@@ -295,7 +295,8 @@ def llc : Tool<
           (switch_on "fPIC"), (append_cmd "-relocation-model=pic"),
           (switch_on "mdynamic-no-pic"),
                      (append_cmd "-relocation-model=dynamic-no-pic"),
-          (not_empty "march"), (forward "march"),
+          (not_empty "march"), (forward_transformed_value
+                                "march", "ConvertMArchToMAttr"),
           (not_empty "mcpu"), (forward "mcpu"),
           (and (not_empty "mtune"), (empty "mcpu")),
                      (forward_as "mtune", "-mcpu"),
diff --git a/tools/llvmc/src/Hooks.cpp b/tools/llvmc/src/Hooks.cpp
index 661a914489d..efc91cf407c 100644
--- a/tools/llvmc/src/Hooks.cpp
+++ b/tools/llvmc/src/Hooks.cpp
@@ -1,14 +1,20 @@
+#include "llvm/ADT/StringMap.h"
+
 #include <string>
 #include <vector>
 
 namespace hooks {
 typedef std::vector<std::string> StrVec;
+typedef llvm::StringMap<const char*> ArgMap;
 
-/// ConvertToMAttr - Convert -m* and -mno-* to -mattr=+*,-*
-std::string ConvertToMAttr(const StrVec& Opts) {
+/// ConvertToMAttrImpl - Common implementation of ConvertMArchToMAttr and
+/// ConvertToMAttr. The optional Args parameter contains information about how
+/// to transform special-cased values (for example, '-march=armv6' must be
+/// forwarded as '-mattr=+v6').
+std::string ConvertToMAttrImpl(const StrVec& Opts, const ArgMap* Args = 0) {
   std::string out("-mattr=");
-
   bool firstIter = true;
+
   for (StrVec::const_iterator B = Opts.begin(), E = Opts.end(); B!=E; ++B) {
     const std::string& Arg = *B;
 
@@ -17,10 +23,23 @@ std::string ConvertToMAttr(const StrVec& Opts) {
     else
       out += ",";
 
+    // Check if the argument is a special case.
+    if (Args != 0) {
+      ArgMap::const_iterator I = Args->find(Arg);
+
+      if (I != Args->end()) {
+        out += '+';
+        out += I->getValue();
+        continue;
+      }
+    }
+
+    // Convert 'no-foo' to '-foo'.
     if (Arg.find("no-") == 0 && Arg[3] != 0) {
       out += '-';
       out += Arg.c_str() + 3;
     }
+    // Convert 'foo' to '+foo'.
     else {
       out += '+';
       out += Arg;
@@ -30,4 +49,36 @@ std::string ConvertToMAttr(const StrVec& Opts) {
   return out;
 }
 
+// Values needed to be special-cased by ConvertMArchToMAttr.
+const char* MArchMapKeys[] = { "armv6" };
+const char* MArchMapValues[] = { "v6" };
+const unsigned NumMArchMapKeys = sizeof(MArchMapKeys) / sizeof(const char*);
+
+void InitializeMArchMap(ArgMap& Args) {
+  for (unsigned i = 0; i < NumMArchMapKeys; ++i) {
+    // Explicit cast to StringRef here is necessary to pick up the right
+    // overload.
+    Args.GetOrCreateValue(llvm::StringRef(MArchMapKeys[i]), MArchMapValues[i]);
+  }
+}
+
+/// ConvertMArchToMAttr - Try to convert -march from the gcc dialect to
+/// something llc can understand.
+std::string ConvertMArchToMAttr(const StrVec& Opts) {
+  static ArgMap MArchMap(NumMArchMapKeys);
+  static bool MArchMapInitialized = false;
+
+  if (!MArchMapInitialized) {
+    InitializeMArchMap(MArchMap);
+    MArchMapInitialized = true;
+  }
+
+  return ConvertToMAttrImpl(Opts, &MArchMap);
+}
+
+/// ConvertToMAttr - Convert '-mfoo' and '-mno-bar' to '-mattr=+foo,-bar'.
+std::string ConvertToMAttr(const StrVec& Opts) {
+  return ConvertToMAttrImpl(Opts);
+}
+
 }