Index: lib/Driver/ToolChains/Hexagon.cpp
===================================================================
--- lib/Driver/ToolChains/Hexagon.cpp
+++ lib/Driver/ToolChains/Hexagon.cpp
@@ -59,7 +59,8 @@
   handleHVXWarnings(D, Args);
 
   // Add the +hvx* features based on commandline flags.
-  StringRef HVXFeature, HVXLength;
+  StringRef HVXFeature;
+  std::string HVXLength;
   StringRef Cpu(toolchains::HexagonToolChain::GetTargetCPUVersion(Args));
 
   // Handle -mhvx, -mhvx=, -mno-hvx, -mno-hvx-double.
@@ -87,17 +88,17 @@
     if (!HasHVX)
       D.Diag(diag::err_drv_invalid_hvx_length);
     else if (A->getOption().matches(options::OPT_mhexagon_hvx_length_EQ))
-      HVXLength = A->getValue();
+      HVXLength = StringRef(A->getValue()).lower();
     else if (A->getOption().matches(options::OPT_mhexagon_hvx_double))
       HVXLength = "128b";
   }
   // Default hvx-length based on Cpu.
   else if (HasHVX)
-    HVXLength = StringRef(getDefaultHvxLength(Cpu));
+    HVXLength = getDefaultHvxLength(Cpu);
 
   if (!HVXLength.empty()) {
     HVXFeature =
-        Args.MakeArgString(llvm::Twine("+hvx-length") + HVXLength.lower());
+        Args.MakeArgString(llvm::Twine("+hvx-length") + HVXLength);
     Features.push_back(HVXFeature);
   }
 }