Revert 96634. It causes assertion failures for 126.gcc and 176.gcc in

the armv6 nightly tests.

llvm-svn: 96691

llvm/include/llvm/Target/TargetRegisterInfo.h

@@ -587,17 +587,6 @@ public:
     return !hasFP(MF);
   }
 
-  /// canSimplifyCallFramePseudos - When possible, it's best to simplify the
-  /// call frame pseudo ops before doing frame index elimination. This is
-  /// possible only when frame index references between the pseudos won't
-  /// need adjusted for the call frame adjustments. Normally, that's true
-  /// if the function has a reserved call frame or a frame pointer. Some
-  /// targets (Thumb2, for example) may have more complicated criteria,
-  /// however, and can override this behavior.
-  virtual bool canSimplifyCallFramePseudos(MachineFunction &MF) const {
-    return hasReservedCallFrame(MF) || hasFP(MF);
-  }
-
   /// hasReservedSpillSlot - Return true if target has reserved a spill slot in
   /// the stack frame of the given function for the specified register. e.g. On
   /// x86, if the frame register is required, the first fixed stack object is

llvm/lib/CodeGen/PrologEpilogInserter.cpp

@@ -175,10 +175,9 @@ void PEI::calculateCallsInformation(MachineFunction &Fn) {
     MachineBasicBlock::iterator I = *i;
 
     // If call frames are not being included as part of the stack frame, and
-    // the target doesn't indicate otherwise, remove the call frame pseudos
-    // here. The sub/add sp instruction pairs are still inserted, but we don't
-    // need to track the SP adjustment for frame index elimination.
-    if (RegInfo->canSimplifyCallFramePseudos(Fn))
+    // there is no dynamic allocation (therefore referencing frame slots off
+    // sp), leave the pseudo ops alone. We'll eliminate them later.
+    if (RegInfo->hasReservedCallFrame(Fn) || RegInfo->hasFP(Fn))
       RegInfo->eliminateCallFramePseudoInstr(Fn, *I->getParent(), I);
   }
 }

llvm/lib/Target/ARM/ARMBaseRegisterInfo.cpp

@@ -1085,16 +1085,6 @@ hasReservedCallFrame(MachineFunction &MF) const {
   return !MF.getFrameInfo()->hasVarSizedObjects();
 }
 
-// canSimplifyCallFramePseudos - If there is a reserved call frame, the
-// call frame pseudos can be simplified. Unlike most targets, having a FP
-// is not sufficient here since we still may reference some objects via SP
-// even when FP is available in Thumb2 mode.
-bool ARMBaseRegisterInfo::
-canSimplifyCallFramePseudos(MachineFunction &MF) const {
-  ARMFunctionInfo *AFI = MF.getInfo<ARMFunctionInfo>();
-  return hasReservedCallFrame(MF) || (AFI->isThumb1OnlyFunction() && hasFP(MF));
-}
-
 static void
 emitSPUpdate(bool isARM,
              MachineBasicBlock &MBB, MachineBasicBlock::iterator &MBBI,
@@ -1159,6 +1149,7 @@ ARMBaseRegisterInfo::eliminateFrameIndex(MachineBasicBlock::iterator II,
   MachineInstr &MI = *II;
   MachineBasicBlock &MBB = *MI.getParent();
   MachineFunction &MF = *MBB.getParent();
+  const MachineFrameInfo *MFI = MF.getFrameInfo();
   ARMFunctionInfo *AFI = MF.getInfo<ARMFunctionInfo>();
   assert(!AFI->isThumb1OnlyFunction() &&
          "This eliminateFrameIndex does not support Thumb1!");
@@ -1169,12 +1160,12 @@ ARMBaseRegisterInfo::eliminateFrameIndex(MachineBasicBlock::iterator II,
   }
 
   int FrameIndex = MI.getOperand(i).getIndex();
+  int Offset = MFI->getObjectOffset(FrameIndex) + MFI->getStackSize() + SPAdj;
   unsigned FrameReg;
 
-  int Offset = getFrameIndexReference(MF, FrameIndex, FrameReg);
+  Offset = getFrameIndexReference(MF, FrameIndex, FrameReg);
   if (FrameReg != ARM::SP)
     SPAdj = 0;
-  Offset += SPAdj;
 
   // Modify MI as necessary to handle as much of 'Offset' as possible
   bool Done = false;

llvm/lib/Target/ARM/ARMBaseRegisterInfo.h

@@ -138,7 +138,6 @@ public:
   virtual bool requiresFrameIndexScavenging(const MachineFunction &MF) const;
 
   virtual bool hasReservedCallFrame(MachineFunction &MF) const;
-  virtual bool canSimplifyCallFramePseudos(MachineFunction &MF) const;
 
   virtual void eliminateCallFramePseudoInstr(MachineFunction &MF,
                                              MachineBasicBlock &MBB,