Reapply bottom-up fast-isel, with several fixes for x86-32:

- Check getBytesToPopOnReturn().
 - Eschew ST0 and ST1 for return values.
 - Fix the PIC base register initialization so that it doesn't ever
   fail to end up the top of the entry block.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@108039 91177308-0d34-0410-b5e6-96231b3b80d8

lib/Target/XCore/XCoreISelLowering.cpp

@@ -1135,13 +1135,12 @@ XCoreTargetLowering::LowerCCCArguments(SDValue Chain,
 
 bool XCoreTargetLowering::
 CanLowerReturn(CallingConv::ID CallConv, bool isVarArg,
-               const SmallVectorImpl<EVT> &OutTys,
-               const SmallVectorImpl<ISD::ArgFlagsTy> &ArgsFlags,
+               const SmallVectorImpl<ISD::OutputArg> &Outs,
                LLVMContext &Context) const {
   SmallVector<CCValAssign, 16> RVLocs;
   CCState CCInfo(CallConv, isVarArg, getTargetMachine(),
                  RVLocs, Context);
-  return CCInfo.CheckReturn(OutTys, ArgsFlags, RetCC_XCore);
+  return CCInfo.CheckReturn(Outs, RetCC_XCore);
 }
 
 SDValue