Index: llvm/lib/Target/ARM/ARMSubtarget.cpp
===================================================================
--- llvm/lib/Target/ARM/ARMSubtarget.cpp
+++ llvm/lib/Target/ARM/ARMSubtarget.cpp
@@ -235,9 +235,12 @@
   if (isTargetMachO() && isTargetIOS() && getTargetTriple().isOSVersionLT(5, 0))
     SupportsTailCall = false;
 
+  // Multi-instruction IT Blocks have been deprecated in ARMv8, additionally
+  // Windows does not permit them, even for older ARM versions.
+
   switch (IT) {
   case DefaultIT:
-    RestrictIT = hasV8Ops() && !hasMinSize();
+    RestrictIT = (hasV8Ops() && !hasMinSize()) || isTargetWindows();
     break;
   case RestrictedIT:
     RestrictIT = true;