1 files changed, 34 insertions, 2 deletions
diff --git a/llvm/lib/CodeGen/MachineRegisterInfo.cpp b/llvm/lib/CodeGen/MachineRegisterInfo.cpp
index 2bb5b054066..8df0d7e0123 100644
--- a/llvm/lib/CodeGen/MachineRegisterInfo.cpp
+++ b/llvm/lib/CodeGen/MachineRegisterInfo.cpp
@@ -42,8 +42,9 @@ static cl::opt<bool> EnableSubRegLiveness("enable-subreg-liveness", cl::Hidden,
 void MachineRegisterInfo::Delegate::anchor() {}
 
 MachineRegisterInfo::MachineRegisterInfo(MachineFunction *MF)
-    : MF(MF), TracksSubRegLiveness(MF->getSubtarget().enableSubRegLiveness() &&
-                                   EnableSubRegLiveness) {
+    : MF(MF), IsUpdatedCSRsInitizialied(false),
+      TracksSubRegLiveness(MF->getSubtarget().enableSubRegLiveness() &&
+                           EnableSubRegLiveness) {
   unsigned NumRegs = getTargetRegisterInfo()->getNumRegs();
   VRegInfo.reserve(256);
   RegAllocHints.reserve(256);
@@ -556,3 +557,34 @@ bool MachineRegisterInfo::isPhysRegUsed(unsigned PhysReg) const {
   }
   return false;
 }
+
+void MachineRegisterInfo::disableCalleeSavedRegister(unsigned Reg) {
+
+  const TargetRegisterInfo *TRI = getTargetRegisterInfo();
+  assert(Reg && (Reg < TRI->getNumRegs()) &&
+         "Trying to disable an invalid register");
+
+  if (!IsUpdatedCSRsInitizialied) {
+    const MCPhysReg *CSR = TRI->getCalleeSavedRegs(MF);
+    for (const MCPhysReg *I = CSR; *I; ++I)
+      UpdatedCSRs.push_back(*I);
+
+    // Zero value represents the end of the register list
+    // (no more registers should be pushed).
+    UpdatedCSRs.push_back(0);
+
+    IsUpdatedCSRsInitizialied = true;
+  }
+
+  // Remove the register (and its aliases from the list).
+  for (MCRegAliasIterator AI(Reg, TRI, true); AI.isValid(); ++AI)
+    UpdatedCSRs.erase(std::remove(UpdatedCSRs.begin(), UpdatedCSRs.end(), *AI),
+                      UpdatedCSRs.end());
+}
+
+const MCPhysReg *MachineRegisterInfo::getCalleeSavedRegs() const {
+  if (IsUpdatedCSRsInitizialied)
+    return UpdatedCSRs.data();
+
+  return getTargetRegisterInfo()->getCalleeSavedRegs(MF);
+}