[XCore] Change std::sort to llvm::sort in response to r327219

[mgrang]

Summary

r327219 added wrappers to std::sort which randomly shuffle the container before sorting.
This will help in uncovering non-determinism caused due to undefined sorting
order of objects having the same key.

To make use of that infrastructure we need to invoke llvm::sort instead of std::sort.

Note: This patch is one of a series of patches to replace *all* std::sort to llvm::sort.
Refer the comments section in D44363 for a list of all the required patches.

[robertlytton]

Hi Mandeep
Thanks for the request.
Looks Good To Me.
robert

lib/Target/XCore/XCoreFrameLowering.cpp

SpillList.push_back(StackSlotInfo(XFI->getLRSpillSlot(),
                                       XCore::LR));
   }
   if (fetchFP) {
     int Offset = MFI.getObjectOffset(XFI->getFPSpillSlot());
     SpillList.push_back(StackSlotInfo(XFI->getFPSpillSlot(),
                                       Offset,
                                       FramePtr));
   }
-  std::sort(SpillList.begin(), SpillList.end(), CompareSSIOffset);
+  llvm::sort(SpillList.begin(), SpillList.end(), CompareSSIOffset);
 }
 
 /// Creates an ordered list of EH info register 'spills'.
 /// These slots are only used by the unwinder and calls to llvm.eh.return().
 /// Registers are ordered according to their frame offset.
 /// As offsets are negative, the largest offsets will be first.
 static void GetEHSpillList(SmallVectorImpl<StackSlotInfo> &SpillList,
                            MachineFrameInfo &MFI, XCoreFunctionInfo *XFI,
                            const Constant *PersonalityFn,
                            const TargetLowering *TL) {
   assert(XFI->hasEHSpillSlot() && "There are no EH register spill slots");
   const int *EHSlot = XFI->getEHSpillSlot();
   SpillList.push_back(
       StackSlotInfo(EHSlot[0], MFI.getObjectOffset(EHSlot[0]),
                     TL->getExceptionPointerRegister(PersonalityFn)));
   SpillList.push_back(
       StackSlotInfo(EHSlot[0], MFI.getObjectOffset(EHSlot[1]),
                     TL->getExceptionSelectorRegister(PersonalityFn)));
-  std::sort(SpillList.begin(), SpillList.end(), CompareSSIOffset);
+  llvm::sort(SpillList.begin(), SpillList.end(), CompareSSIOffset);
 }
 
 static MachineMemOperand *getFrameIndexMMO(MachineBasicBlock &MBB,
                                            int FrameIndex,
                                            MachineMemOperand::Flags flags) {
   MachineFunction *MF = MBB.getParent();
   const MachineFrameInfo &MFI = MF->getFrameInfo();
   MachineMemOperand *MMO = MF->getMachineMemOperand(

lib/Target/XCore/XCoreLowerThreadLocal.cpp

switch (OpCode) {
     default:
       llvm_unreachable("Unhandled constant expression!\n");
   }
 }
 
 static bool replaceConstantExprOp(ConstantExpr *CE, Pass *P) {
   do {
     SmallVector<WeakTrackingVH, 8> WUsers(CE->user_begin(), CE->user_end());
-    std::sort(WUsers.begin(), WUsers.end());
+    llvm::sort(WUsers.begin(), WUsers.end());
     WUsers.erase(std::unique(WUsers.begin(), WUsers.end()), WUsers.end());
     while (!WUsers.empty())
       if (WeakTrackingVH WU = WUsers.pop_back_val()) {
         if (PHINode *PN = dyn_cast<PHINode>(WU)) {
           for (int I = 0, E = PN->getNumIncomingValues(); I < E; ++I)
             if (PN->getIncomingValue(I) == CE) {
               BasicBlock *PredBB = PN->getIncomingBlock(I);
               if (PredBB->getTerminator()->getNumSuccessors() > 1)