2 files changed, 15 insertions, 0 deletions
diff --git a/llvm/lib/Target/PowerPC/PPCRegisterInfo.cpp b/llvm/lib/Target/PowerPC/PPCRegisterInfo.cpp
index aad91392469..637e52bbdbe 100644
--- a/llvm/lib/Target/PowerPC/PPCRegisterInfo.cpp
+++ b/llvm/lib/Target/PowerPC/PPCRegisterInfo.cpp
@@ -273,6 +273,20 @@ BitVector PPCRegisterInfo::getReservedRegs(const MachineFunction &MF) const {
   return Reserved;
 }
 
+bool PPCRegisterInfo::isCallerPreservedPhysReg(unsigned PhysReg,
+                                               const MachineFunction &MF) const {
+  assert(TargetRegisterInfo::isPhysicalRegister(PhysReg));
+  if (TM.isELFv2ABI() && PhysReg == PPC::X2) {
+    // X2 is guaranteed to be preserved within a function if it is reserved.
+    // The reason it's reserved is that it's the TOC pointer (and the function
+    // uses the TOC). In functions where it isn't reserved (i.e. leaf functions
+    // with no TOC access), we can't claim that it is preserved.
+    return (getReservedRegs(MF).test(PPC::X2));
+  } else {
+    return false;
+  }
+}
+
 unsigned PPCRegisterInfo::getRegPressureLimit(const TargetRegisterClass *RC,
                                               MachineFunction &MF) const {
   const PPCFrameLowering *TFI = getFrameLowering(MF);
diff --git a/llvm/lib/Target/PowerPC/PPCRegisterInfo.h b/llvm/lib/Target/PowerPC/PPCRegisterInfo.h
index 4a96327fe55..0bbb71fdf9f 100644
--- a/llvm/lib/Target/PowerPC/PPCRegisterInfo.h
+++ b/llvm/lib/Target/PowerPC/PPCRegisterInfo.h
@@ -83,6 +83,7 @@ public:
   void adjustStackMapLiveOutMask(uint32_t *Mask) const override;
 
   BitVector getReservedRegs(const MachineFunction &MF) const override;
+  bool isCallerPreservedPhysReg(unsigned PhysReg, const MachineFunction &MF) const override;
 
   /// We require the register scavenger.
   bool requiresRegisterScavenging(const MachineFunction &MF) const override {