Index: llvm/trunk/lib/CodeGen/TargetLoweringObjectFileImpl.cpp
===================================================================
--- llvm/trunk/lib/CodeGen/TargetLoweringObjectFileImpl.cpp
+++ llvm/trunk/lib/CodeGen/TargetLoweringObjectFileImpl.cpp
@@ -932,7 +932,7 @@
       StringRef Op = MDOption->getString();
       // Lead with a space for consistency with our dllexport implementation.
       std::string Escaped(" ");
-      if (Op.find(" ") != StringRef::npos) {
+      if (!Op.startswith("\"") && (Op.find(" ") != StringRef::npos)) {
         // The PE-COFF spec says args with spaces must be quoted.  It doesn't say
         // how to escape quotes, but it probably uses this algorithm:
         // http://msdn.microsoft.com/en-us/library/17w5ykft(v=vs.85).aspx
Index: llvm/trunk/test/MC/COFF/linker-options.ll
===================================================================
--- llvm/trunk/test/MC/COFF/linker-options.ll
+++ llvm/trunk/test/MC/COFF/linker-options.ll
@@ -1,6 +1,6 @@
 ; RUN: llc -O0 -mtriple=i386-pc-win32 -filetype=asm -o - %s | FileCheck %s
 
-!0 = !{i32 6, !"Linker Options", !{!{!"/DEFAULTLIB:msvcrt.lib"}, !{!"/DEFAULTLIB:msvcrt.lib", !"/DEFAULTLIB:secur32.lib"}, !{!"/DEFAULTLIB:C:\5Cpath to\5Casan_rt.lib"}, !{!"/with spaces"}}}
+!0 = !{i32 6, !"Linker Options", !{!{!"/DEFAULTLIB:msvcrt.lib"}, !{!"/DEFAULTLIB:msvcrt.lib", !"/DEFAULTLIB:secur32.lib"}, !{!"/DEFAULTLIB:C:\5Cpath to\5Casan_rt.lib"}, !{!"/with spaces"}, !{!"\22/quoted spaces\22"}}}
 
 !llvm.module.flags = !{ !0 }
 
@@ -14,4 +14,5 @@
 ; CHECK: .ascii   " /DEFAULTLIB:secur32.lib"
 ; CHECK: .ascii   " \"/DEFAULTLIB:C:\\path to\\asan_rt.lib\""
 ; CHECK: .ascii   " \"/with spaces\""
+; CHECK: .ascii   " \"/quoted spaces\""
 ; CHECK: .ascii   " /EXPORT:_foo"