Index: test/tools/llvm-ar/case-detection.test
===================================================================
--- test/tools/llvm-ar/case-detection.test
+++ test/tools/llvm-ar/case-detection.test
@@ -0,0 +1,11 @@
+-- Test CamelCase tool name to ensure detection works properly
+
+RUN: yaml2obj %S/Inputs/coff.yaml -o %t.obj
+RUN: rm -rf %t1
+RUN: mkdir %t1
+RUN: cp llvm-ar %t1/Lib
+RUN: %t1/Lib /OUT:%t.lib %t.obj | FileCheck %s -allow-empty
+RUN: cp llvm-ar %t1/Ar
+RUN: %t1/Ar crs %t.ar %t.obj | FileCheck %s -allow-empty
+
+CHECK-NOT: OVERVIEW: LLVM Archiver (llvm-ar)
Index: tools/llvm-ar/llvm-ar.cpp
===================================================================
--- tools/llvm-ar/llvm-ar.cpp
+++ tools/llvm-ar/llvm-ar.cpp
@@ -26,6 +26,7 @@
 #include "llvm/Support/Errc.h"
 #include "llvm/Support/FileSystem.h"
 #include "llvm/Support/Format.h"
+#include "llvm/Support/FormatVariadic.h"
 #include "llvm/Support/LineIterator.h"
 #include "llvm/Support/ManagedStatic.h"
 #include "llvm/Support/MemoryBuffer.h"
@@ -57,7 +58,7 @@
 
   This program generates an index to speed access to archives
 
-USAGE: llvm-ranlib <archive-file>
+USAGE: {0} <archive-file>
 
 OPTIONS:
   -help                             - Display available options
@@ -69,7 +70,7 @@
 
   This program archives bitcode files into single libraries
 
-USAGE: llvm-ar [options] [relpos] [count] <archive-file> [members]...
+USAGE: {0} [options] [relpos] [count] <archive-file> [members]...
 
 OPTIONS:
   -M                                -
@@ -109,10 +110,10 @@
 )";
 
 void printHelpMessage() {
-  if (Stem.find("ranlib") != StringRef::npos)
-    outs() << RanlibHelp;
-  else if (Stem.find("ar") != StringRef::npos)
-    outs() << ArHelp;
+  if (Stem.find_lower("ranlib") != StringRef::npos)
+    outs() << formatv(RanlibHelp, Stem);
+  else if (Stem.find_lower("ar") != StringRef::npos)
+    outs() << formatv(ArHelp, Stem);
 }
 
 // Show the error message and exit.
@@ -960,16 +961,16 @@
   llvm::InitializeAllAsmParsers();
 
   Stem = sys::path::stem(ToolName);
-  if (Stem.find("dlltool") != StringRef::npos)
+  if (Stem.find_lower("dlltool") != StringRef::npos)
     return dlltoolDriverMain(makeArrayRef(argv, argc));
 
-  if (Stem.find("ranlib") != StringRef::npos)
+  if (Stem.find_lower("ranlib") != StringRef::npos)
     return ranlib_main(argc, argv);
 
-  if (Stem.find("lib") != StringRef::npos)
+  if (Stem.find_lower("lib") != StringRef::npos)
     return libDriverMain(makeArrayRef(argv, argc));
 
-  if (Stem.find("ar") != StringRef::npos)
+  if (Stem.find_lower("ar") != StringRef::npos)
     return ar_main(argc, argv);
   fail("Not ranlib, ar, lib or dlltool!");
 }