Protect R31's frame offset from being used by callee-saved registers, when R31
is the frame pointer.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@35233 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Target/PowerPC/PPCRegisterInfo.cpp b/lib/Target/PowerPC/PPCRegisterInfo.cpp
index 0b9602b..a2ee919 100644
--- a/lib/Target/PowerPC/PPCRegisterInfo.cpp
+++ b/lib/Target/PowerPC/PPCRegisterInfo.cpp
@@ -891,6 +891,26 @@
unsigned LR = getRARegister();
FI->setUsesLR(MF.isPhysRegUsed(LR));
MF.changePhyRegUsed(LR, false);
+
+
+ // Save R31 if necessary
+ int FPSI = FI->getFramePointerSaveIndex();
+ bool IsPPC64 = Subtarget.isPPC64();
+ bool IsELF_ABI = Subtarget.isELF_ABI();
+ const MachineFrameInfo *MFI = MF.getFrameInfo();
+
+ // If the frame pointer save index hasn't been defined yet.
+ if (!FPSI && (NoFramePointerElim || MFI->hasVarSizedObjects())
+ && IsELF_ABI) {
+ // Find out what the fix offset of the frame pointer save area.
+ int FPOffset = PPCFrameInfo::getFramePointerSaveOffset(IsPPC64,
+ !IsELF_ABI);
+ // Allocate the frame index for frame pointer save area.
+ FPSI = MF.getFrameInfo()->CreateFixedObject(IsPPC64? 8 : 4, FPOffset);
+ // Save the result.
+ FI->setFramePointerSaveIndex(FPSI);
+ }
+
}
void PPCRegisterInfo::emitPrologue(MachineFunction &MF) const {