Revert "X86RegisterInfo: eliminateFrameIndex: Avoid code duplication; NFC"

It seems we have on situation in a sanitizer enable bootstrap build
where the return instruction has a frame index operand that does not
point to a fixed object and fails the assert added here.

This reverts commit r300923.
This reverts commit r300922.

llvm-svn: 301024
diff --git a/llvm/lib/Target/X86/X86FrameLowering.cpp b/llvm/lib/Target/X86/X86FrameLowering.cpp
index 6dddb10..8678a13 100644
--- a/llvm/lib/Target/X86/X86FrameLowering.cpp
+++ b/llvm/lib/Target/X86/X86FrameLowering.cpp
@@ -1783,14 +1783,6 @@
   return Offset + FPDelta;
 }
 
-int X86FrameLowering::getFrameIndexReferenceSP(const MachineFunction &MF,
-                                               int FI, unsigned &FrameReg,
-                                               int Adjustment) const {
-  const MachineFrameInfo &MFI = MF.getFrameInfo();
-  FrameReg = TRI->getStackRegister();
-  return MFI.getObjectOffset(FI) - getOffsetOfLocalArea() + Adjustment;
-}
-
 int
 X86FrameLowering::getFrameIndexReferencePreferSP(const MachineFunction &MF,
                                                  int FI, unsigned &FrameReg,
@@ -1847,6 +1839,9 @@
   assert(MF.getInfo<X86MachineFunctionInfo>()->getTCReturnAddrDelta() >= 0 &&
          "we don't handle this case!");
 
+  // Fill in FrameReg output argument.
+  FrameReg = TRI->getStackRegister();
+
   // This is how the math works out:
   //
   //  %rsp grows (i.e. gets lower) left to right. Each box below is
@@ -1871,8 +1866,12 @@
   // (C - E) == (C - A) - (B - A) + (B - E)
   //            { Using [1], [2] and [3] above }
   //         == getObjectOffset - LocalAreaOffset + StackSize
+  //
 
-  return getFrameIndexReferenceSP(MF, FI, FrameReg, StackSize);
+  // Get the Offset from the StackPointer
+  int Offset = MFI.getObjectOffset(FI) - getOffsetOfLocalArea();
+
+  return Offset + StackSize;
 }
 
 bool X86FrameLowering::assignCalleeSavedSpillSlots(