Index: lib/Driver/Tools.cpp
===================================================================
--- lib/Driver/Tools.cpp	(revision 146670)
+++ lib/Driver/Tools.cpp	(working copy)
@@ -966,6 +966,7 @@
   Arg *A;
   llvm::StringRef WhichHexagon;
 
+  // Select the default CPU (v4) if none was given or detection failed.
   if ((A = getLastHexagonArchArg (Args))) {
     if ((A->getOption().matches(options::OPT_march_EQ)) ||
         (A->getOption().matches(options::OPT_mcpu_EQ))) {
@@ -977,7 +978,7 @@
       else if (WhichHexagon == "v4")
         return "hexagonv4";
       else
-        assert (0 && "Unknown -march or -mcpu value");
+        return "hexagonv4";
     }
     else {
       if (A->getOption().matches(options::OPT_mv2))
@@ -986,11 +987,9 @@
         return "hexagonv3";
       else if (A->getOption().matches(options::OPT_mv4))
         return "hexagonv4";
-      else
-        assert(0 && "Unknown -m argument.");
     }
   }
-  return "hexagonv2";
+  return "hexagonv4";
 }
 
 void Clang::AddHexagonTargetArgs(const ArgList &Args,
@@ -2774,6 +2773,7 @@
   RenderExtraToolArgs(JA, CmdArgs);
 
   // Add Arch Information
+  // Select the default CPU (v4) if none was given or detection failed.
   Arg *A;
   if ((A = getLastHexagonArchArg (Args))) {
     if ((A->getOption().matches(options::OPT_march_EQ)) ||
@@ -2786,18 +2786,18 @@
     else if (WhichHexagon == "v4")
       CmdArgs.push_back ("-mv4");
     else
-      assert (0 && "Unknown -march or -mcpu value");
+      CmdArgs.push_back ("-mv4");
     }
-    else {
-      if (A->getOption().matches(options::OPT_mv2) ||
-          A->getOption().matches(options::OPT_mv3) ||
-          A->getOption().matches(options::OPT_mv4))
-        A->render(Args, CmdArgs);
-      else
-        assert(0 && "Unknown -m argument.");
+    else if (A->getOption().matches(options::OPT_mv2) ||
+             A->getOption().matches(options::OPT_mv3) ||
+             A->getOption().matches(options::OPT_mv4)) {
+      A->render(Args, CmdArgs);
     }
+  }
+  else {
+    CmdArgs.push_back ("-mv4");
+  }
 
-  }
   CmdArgs.push_back("-mqdsp6-compat");
 
   const char *GCCName;