Index: COFF/Driver.cpp
===================================================================
--- COFF/Driver.cpp
+++ COFF/Driver.cpp
@@ -377,7 +377,17 @@
   bool HasExt = Filename.contains('.');
   if (!HasExt)
     Filename = Saver.save(Filename + ".lib");
-  return doFindFile(Filename);
+  StringRef Ret = doFindFile(Filename);
+  if (Config->MinGW && Ret == Filename && HasExt && !Filename.contains('/') &&
+      !Filename.contains('\\')) {
+    SmallString<128> S = Filename;
+    sys::path::replace_extension(S, ".a");
+    StringRef LibName = Saver.save("lib" + S.str());
+    StringRef LibNameRet = doFindFile(LibName);
+    if (LibNameRet != LibName)
+      return LibNameRet;
+  }
+  return Ret;
 }
 
 // Resolves a library path. /nodefaultlib options are taken into
Index: test/COFF/libname-mingw.test
===================================================================
--- /dev/null
+++ test/COFF/libname-mingw.test
@@ -0,0 +1,8 @@
+# RUN: mkdir -p %t/a
+# RUN: cp %p/Inputs/std64.lib %t/a/libstd64.a
+
+# RUN: lld-link /lldmingw /out:%t.exe /entry:main /verbose \
+# RUN:   /defaultlib:std64.lib /subsystem:console %p/Inputs/hello64.obj \
+# RUN:   /libpath:%t/a 2>&1 | FileCheck %s
+
+CHECK: a{{[/\\]}}libstd64.a