Index: llvm/test/tools/llvm-cxxfilt/simple.test
===================================================================
--- llvm/test/tools/llvm-cxxfilt/simple.test
+++ llvm/test/tools/llvm-cxxfilt/simple.test
@@ -1,4 +1,6 @@
 RUN: llvm-cxxfilt _Z1fi abc | FileCheck %s
+RUN: llvm-cxxfilt "Mangled _Z1fi and _Z3foov in string." | FileCheck %s --check-prefix=CHECK-STRING
 
 CHECK: f(int)
 CHECK-NEXT: abc
+CHECK-STRING: Mangled f(int) and foo() in string.
Index: llvm/test/tools/llvm-cxxfilt/types.test
===================================================================
--- llvm/test/tools/llvm-cxxfilt/types.test
+++ llvm/test/tools/llvm-cxxfilt/types.test
@@ -1,5 +1,6 @@
 RUN: llvm-cxxfilt -t f i | FileCheck %s
+RUN: llvm-cxxfilt -t "f i" | FileCheck %s --check-prefix="CHECK-STRING"
 
 CHECK: float
 CHECK-NEXT: int
-
+CHECK-STRING: float int
Index: llvm/tools/llvm-cxxfilt/llvm-cxxfilt.cpp
===================================================================
--- llvm/tools/llvm-cxxfilt/llvm-cxxfilt.cpp
+++ llvm/tools/llvm-cxxfilt/llvm-cxxfilt.cpp
@@ -6,6 +6,9 @@
 //
 //===----------------------------------------------------------------------===//
 
+#include "llvm/ADT/SmallVector.h"
+#include "llvm/ADT/StringExtras.h"
+#include "llvm/ADT/StringRef.h"
 #include "llvm/Demangle/Demangle.h"
 #include "llvm/Support/CommandLine.h"
 #include "llvm/Support/InitLLVM.h"
@@ -51,7 +54,7 @@
 static cl::list<std::string>
 Decorated(cl::Positional, cl::desc("<mangled>"), cl::ZeroOrMore);
 
-static void demangle(llvm::raw_ostream &OS, const std::string &Mangled) {
+static std::string demangle(llvm::raw_ostream &OS, const std::string &Mangled) {
   int Status;
 
   const char *Decorated = Mangled.c_str();
@@ -72,10 +75,24 @@
     Undecorated = itaniumDemangle(Decorated + 6, nullptr, nullptr, &Status);
   }
 
-  OS << (Undecorated ? Undecorated : Mangled) << '\n';
-  OS.flush();
-
+  std::string Result(Undecorated ? Undecorated : Mangled);
   free(Undecorated);
+  return Result;
+}
+
+// Split 'Mangled' and demangle each word.
+// The result is reconstructed and output to 'OS'.
+static void demangleLine(llvm::raw_ostream &OS, const std::string &Mangled) {
+  SmallVector<StringRef, 16> Words;
+  SplitString(Mangled, Words);
+  std::string Result;
+  for (auto Word : Words)
+    Result += demangle(OS, Word) + ' ';
+  // Remove the trailing space character.
+  if (Result.back() == ' ')
+    Result.pop_back();
+  OS << Result << '\n';
+  OS.flush();
 }
 
 int main(int argc, char **argv) {
@@ -85,10 +102,10 @@
 
   if (Decorated.empty())
     for (std::string Mangled; std::getline(std::cin, Mangled);)
-      demangle(llvm::outs(), Mangled);
+      demangleLine(llvm::outs(), Mangled);
   else
     for (const auto &Symbol : Decorated)
-      demangle(llvm::outs(), Symbol);
+      demangleLine(llvm::outs(), Symbol);
 
   return EXIT_SUCCESS;
 }