diff --git a/lib/Target/X86/X86FrameLowering.cpp b/lib/Target/X86/X86FrameLowering.cpp
index cf4e42785b3..adcd4f7dedc 100644
--- a/lib/Target/X86/X86FrameLowering.cpp
+++ b/lib/Target/X86/X86FrameLowering.cpp
@@ -606,7 +606,7 @@ void X86FrameLowering::emitPrologue(MachineFunction &MF) const {
   // responsible for adjusting the stack pointer.  Touching the stack at 4K
   // increments is necessary to ensure that the guard pages used by the OS
   // virtual memory manager are allocated in correct sequence.
-  if (NumBytes >= 4096 && STI.isOSWindows()) {
+  if (NumBytes >= 4096 && STI.isTargetCOFF() && !STI.isTargetEnvMacho()) {
     const char *StackProbeSymbol;
     bool isSPUpdateNeeded = false;
 
diff --git a/lib/Target/X86/X86ISelLowering.cpp b/lib/Target/X86/X86ISelLowering.cpp
index 694623e1754..cc409fb3c51 100644
--- a/lib/Target/X86/X86ISelLowering.cpp
+++ b/lib/Target/X86/X86ISelLowering.cpp
@@ -631,7 +631,7 @@ void X86TargetLowering::resetOperationActions() {
   setOperationAction(ISD::STACKSAVE,          MVT::Other, Expand);
   setOperationAction(ISD::STACKRESTORE,       MVT::Other, Expand);
 
-  if (Subtarget->isTargetWindows())
+  if (Subtarget->isTargetCOFF() && !Subtarget->isTargetEnvMacho())
     setOperationAction(ISD::DYNAMIC_STACKALLOC, Subtarget->is64Bit() ?
                        MVT::i64 : MVT::i32, Custom);
   else if (TM.Options.EnableSegmentedStacks)
diff --git a/lib/Target/X86/X86Subtarget.h b/lib/Target/X86/X86Subtarget.h
index dd8c0811ce5..fb357c46756 100644
--- a/lib/Target/X86/X86Subtarget.h
+++ b/lib/Target/X86/X86Subtarget.h
@@ -333,8 +333,6 @@ public:
   }
   bool isTargetEnvMacho() const { return TargetTriple.isEnvironmentMachO(); }
 
-  bool isOSWindows() const { return TargetTriple.isOSWindows(); }
-
   bool isTargetWin64() const {
     return In64BitMode && TargetTriple.isOSWindows();
   }