ARM: consolidate frame pointer register knowledge

Use the ARMBaseRegisterInfo to query the frame register.  The base register info
is aware of the frame register that is used for the frame pointer.  Use that to
determine the frame register rather than duplicating the knowledge.  Although,
the code path is slightly different in that it may return SP, that can only
occur if the frame pointer has been omitted in the machine function, which is
supposed to contain the desired value in that case.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@209084 91177308-0d34-0410-b5e6-96231b3b80d8

diff --git a/lib/Target/ARM/ARMISelLowering.cpp b/lib/Target/ARM/ARMISelLowering.cpp
index c7a3ab82fca7d005776d00e87475c52cff532c68..5d36f1a995ed6d5eeb7c1673d5ed82fad2cbe527 100644 (file)
--- a/lib/Target/ARM/ARMISelLowering.cpp
+++ b/lib/Target/ARM/ARMISelLowering.cpp
@@ -3930,14 +3930,16 @@ SDValue ARMTargetLowering::LowerRETURNADDR(SDValue Op, SelectionDAG &DAG) const{
 }
 
 SDValue ARMTargetLowering::LowerFRAMEADDR(SDValue Op, SelectionDAG &DAG) const {
-  MachineFrameInfo *MFI = DAG.getMachineFunction().getFrameInfo();
+  const ARMBaseRegisterInfo &ARI =
+    *static_cast<const ARMBaseRegisterInfo*>(RegInfo);
+  MachineFunction &MF = DAG.getMachineFunction();
+  MachineFrameInfo *MFI = MF.getFrameInfo();
   MFI->setFrameAddressIsTaken(true);
 
   EVT VT = Op.getValueType();
   SDLoc dl(Op);  // FIXME probably not meaningful
   unsigned Depth = cast<ConstantSDNode>(Op.getOperand(0))->getZExtValue();
-  unsigned FrameReg = (Subtarget->isThumb() || Subtarget->isTargetMachO())
-    ? ARM::R7 : ARM::R11;
+  unsigned FrameReg = ARI.getFrameRegister(MF);
   SDValue FrameAddr = DAG.getCopyFromReg(DAG.getEntryNode(), dl, FrameReg, VT);
   while (Depth--)
     FrameAddr = DAG.getLoad(VT, dl, DAG.getEntryNode(), FrameAddr,