diff --git a/lib/LibDriver/LibDriver.cpp b/lib/LibDriver/LibDriver.cpp
index cb3278c716e..bc3ed46040c 100644
--- a/lib/LibDriver/LibDriver.cpp
+++ b/lib/LibDriver/LibDriver.cpp
@@ -56,17 +56,13 @@ public:
 
 }
 
-static std::string getOutputPath(llvm::opt::InputArgList *Args) {
+static std::string getOutputPath(llvm::opt::InputArgList *Args,
+                                 const llvm::NewArchiveIterator &FirstMember) {
   if (auto *Arg = Args->getLastArg(OPT_out))
     return Arg->getValue();
-  for (auto *Arg : Args->filtered(OPT_INPUT)) {
-    if (!StringRef(Arg->getValue()).endswith_lower(".obj"))
-      continue;
-    SmallString<128> Val = StringRef(Arg->getValue());
-    llvm::sys::path::replace_extension(Val, ".lib");
-    return Val.str();
-  }
-  llvm_unreachable("internal error");
+  SmallString<128> Val = FirstMember.getNew();
+  llvm::sys::path::replace_extension(Val, ".lib");
+  return Val.str();
 }
 
 static std::vector<StringRef> getSearchPaths(llvm::opt::InputArgList *Args,
@@ -143,8 +139,8 @@ int llvm::libDriverMain(llvm::ArrayRef<const char*> ArgsArr) {
                          llvm::sys::path::filename(Arg->getValue()));
   }
 
-  std::pair<StringRef, std::error_code> Result =
-      llvm::writeArchive(getOutputPath(&Args), Members, /*WriteSymtab=*/true);
+  std::pair<StringRef, std::error_code> Result = llvm::writeArchive(
+      getOutputPath(&Args, Members[0]), Members, /*WriteSymtab=*/true);
   if (Result.second) {
     if (Result.first.empty())
       Result.first = ArgsArr[0];
diff --git a/test/LibDriver/infer-output-path.test b/test/LibDriver/infer-output-path.test
new file mode 100644
index 00000000000..7a1bbcbbd18
--- /dev/null
+++ b/test/LibDriver/infer-output-path.test
@@ -0,0 +1,15 @@
+RUN: llvm-mc -triple=x86_64-pc-windows-msvc -filetype=obj -o %T/a.obj %S/Inputs/a.s
+RUN: llvm-mc -triple=x86_64-pc-windows-msvc -filetype=obj -o %T/b.o %S/Inputs/b.s
+RUN: llvm-mc -triple=x86_64-pc-windows-msvc -filetype=obj -o %T/c %S/Inputs/b.s
+
+RUN: rm -f %T/a.lib
+RUN: llvm-lib %T/a.obj
+RUN: test -e %T/a.lib
+
+RUN: rm -f %T/b.lib
+RUN: llvm-lib /libpath:%T b.o
+RUN: test -e %T/b.lib
+
+RUN: rm -f %T/c.lib
+RUN: llvm-lib /libpath:%T c
+RUN: test -e %T/c.lib