XCore target: Lower FRAME_TO_ARGS_OFFSET

This requires a knowledge of the stack size which is not known until
the frame is complete, hence the need for the XCoreFTAOElim pass
which lowers the XCoreISD::FRAME_TO_ARGS_OFFSET instrution into its
final form.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@198614 91177308-0d34-0410-b5e6-96231b3b80d8

lib/Target/XCore/XCoreTargetMachine.cpp

@@ -48,6 +48,7 @@ public:
 
   virtual bool addPreISel();
   virtual bool addInstSelector();
+  virtual bool addPreEmitPass();
 };
 } // namespace
 
@@ -65,6 +66,11 @@ bool XCorePassConfig::addInstSelector() {
   return false;
 }
 
+bool XCorePassConfig::addPreEmitPass() {
+  addPass(createXCoreFrameToArgsOffsetEliminationPass());
+  return false;
+}
+
 // Force static initialization.
 extern "C" void LLVMInitializeXCoreTarget() {
   RegisterTargetMachine<XCoreTargetMachine> X(TheXCoreTarget);