Thumb2 instructions are enabled only in unified assembler mode.

Emit switch directive for it. I have no idea whether this is
requirement for Darwin or not.

llvm-svn: 73660

llvm/lib/Target/ARM/AsmPrinter/ARMAsmPrinter.cpp

@@ -840,6 +840,10 @@ bool ARMAsmPrinter::doInitialization(Module &M) {
   if (Subtarget->isTargetDarwin())
     Mang->setUseQuotes(true);
 
+  // Thumb-2 instructions are supported only in unified assembler syntax mode.
+  if (Subtarget->isTargetELF() && Subtarget->hasThumb2())
+    O << "\t.syntax unified\n";
+
   // Emit ARM Build Attributes
   if (Subtarget->isTargetELF()) {
     // CPU Type