1 files changed, 55 insertions, 34 deletions

diff --git a/lib/CodeGen/LivePhysRegs.cpp b/lib/CodeGen/LivePhysRegs.cpp
index 9f7d7cf54848..0dc1079b2ad4 100644
--- a/lib/CodeGen/LivePhysRegs.cpp
+++ b/lib/CodeGen/LivePhysRegs.cpp
@@ -53,7 +53,7 @@ void LivePhysRegs::stepBackward(const MachineInstr &MI) {
         continue;
       removeReg(Reg);
     } else if (O->isRegMask())
-      removeRegsInMask(*O, nullptr);
+      removeRegsInMask(*O);
   }
 
   // Add uses to the set.
@@ -142,66 +142,85 @@ bool LivePhysRegs::available(const MachineRegisterInfo &MRI,
 /// Add live-in registers of basic block \p MBB to \p LiveRegs.
 void LivePhysRegs::addBlockLiveIns(const MachineBasicBlock &MBB) {
   for (const auto &LI : MBB.liveins()) {
-    MCSubRegIndexIterator S(LI.PhysReg, TRI);
-    if (LI.LaneMask.all() || (LI.LaneMask.any() && !S.isValid())) {
-      addReg(LI.PhysReg);
+    unsigned Reg = LI.PhysReg;
+    LaneBitmask Mask = LI.LaneMask;
+    MCSubRegIndexIterator S(Reg, TRI);
+    assert(Mask.any() && "Invalid livein mask");
+    if (Mask.all() || !S.isValid()) {
+      addReg(Reg);
       continue;
     }
     for (; S.isValid(); ++S) {
       unsigned SI = S.getSubRegIndex();
-      if ((LI.LaneMask & TRI->getSubRegIndexLaneMask(SI)).any())
+      if ((Mask & TRI->getSubRegIndexLaneMask(SI)).any())
         addReg(S.getSubReg());
     }
   }
 }
 
-/// Add pristine registers to the given \p LiveRegs. This function removes
-/// actually saved callee save registers when \p InPrologueEpilogue is false.
-static void addPristines(LivePhysRegs &LiveRegs, const MachineFunction &MF,
-                         const MachineFrameInfo &MFI,
-                         const TargetRegisterInfo &TRI) {
+/// Adds all callee saved registers to \p LiveRegs.
+static void addCalleeSavedRegs(LivePhysRegs &LiveRegs,
+                               const MachineFunction &MF) {
   const MachineRegisterInfo &MRI = MF.getRegInfo();
-  for (const MCPhysReg *CSR = MRI.getCalleeSavedRegs(); CSR && *CSR;
-       ++CSR)
+  for (const MCPhysReg *CSR = MRI.getCalleeSavedRegs(); CSR && *CSR; ++CSR)
     LiveRegs.addReg(*CSR);
+}
+
+/// Adds pristine registers to the given \p LiveRegs. Pristine registers are
+/// callee saved registers that are unused in the function.
+static void addPristines(LivePhysRegs &LiveRegs, const MachineFunction &MF) {
+  const MachineFrameInfo &MFI = MF.getFrameInfo();
+  if (!MFI.isCalleeSavedInfoValid())
+    return;
+  /// Add all callee saved regs, then remove the ones that are saved+restored.
+  addCalleeSavedRegs(LiveRegs, MF);
+  /// Remove the ones that are not saved/restored; they are pristine.
   for (const CalleeSavedInfo &Info : MFI.getCalleeSavedInfo())
     LiveRegs.removeReg(Info.getReg());
 }
 
 void LivePhysRegs::addLiveOutsNoPristines(const MachineBasicBlock &MBB) {
-  // To get the live-outs we simply merge the live-ins of all successors.
-  for (const MachineBasicBlock *Succ : MBB.successors())
-    addBlockLiveIns(*Succ);
+  if (!MBB.succ_empty()) {
+    // To get the live-outs we simply merge the live-ins of all successors.
+    for (const MachineBasicBlock *Succ : MBB.successors())
+      addBlockLiveIns(*Succ);
+  } else if (MBB.isReturnBlock()) {
+    // For the return block: Add all callee saved registers that are saved and
+    // restored (somewhere); This does not include callee saved registers that
+    // are unused and hence not saved and restored; they are called pristine.
+    const MachineFunction &MF = *MBB.getParent();
+    const MachineFrameInfo &MFI = MF.getFrameInfo();
+    if (MFI.isCalleeSavedInfoValid()) {
+      for (const CalleeSavedInfo &Info : MFI.getCalleeSavedInfo())
+        addReg(Info.getReg());
+    }
+  }
 }
 
 void LivePhysRegs::addLiveOuts(const MachineBasicBlock &MBB) {
-  const MachineFunction &MF = *MBB.getParent();
-  const MachineFrameInfo &MFI = MF.getFrameInfo();
-  if (MFI.isCalleeSavedInfoValid()) {
-    if (MBB.isReturnBlock()) {
-      // The return block has no successors whose live-ins we could merge
-      // below. So instead we add the callee saved registers manually.
-      const MachineRegisterInfo &MRI = MF.getRegInfo();
-      for (const MCPhysReg *I = MRI.getCalleeSavedRegs(); *I; ++I)
-        addReg(*I);
-    } else {
-      addPristines(*this, MF, MFI, *TRI);
-    }
+  if (!MBB.succ_empty()) {
+    const MachineFunction &MF = *MBB.getParent();
+    addPristines(*this, MF);
+    addLiveOutsNoPristines(MBB);
+  } else if (MBB.isReturnBlock()) {
+    // For the return block: Add all callee saved registers.
+    const MachineFunction &MF = *MBB.getParent();
+    const MachineFrameInfo &MFI = MF.getFrameInfo();
+    if (MFI.isCalleeSavedInfoValid())
+      addCalleeSavedRegs(*this, MF);
   }
-
-  addLiveOutsNoPristines(MBB);
 }
 
 void LivePhysRegs::addLiveIns(const MachineBasicBlock &MBB) {
   const MachineFunction &MF = *MBB.getParent();
-  const MachineFrameInfo &MFI = MF.getFrameInfo();
-  if (MFI.isCalleeSavedInfoValid())
-    addPristines(*this, MF, MFI, *TRI);
+  addPristines(*this, MF);
   addBlockLiveIns(MBB);
 }
 
-void llvm::computeLiveIns(LivePhysRegs &LiveRegs, const TargetRegisterInfo &TRI,
+void llvm::computeLiveIns(LivePhysRegs &LiveRegs,
+                          const MachineRegisterInfo &MRI,
                           MachineBasicBlock &MBB) {
+  const TargetRegisterInfo &TRI = *MRI.getTargetRegisterInfo();
   assert(MBB.livein_empty());
   LiveRegs.init(TRI);
   LiveRegs.addLiveOutsNoPristines(MBB);
@@ -209,10 +228,12 @@ void llvm::computeLiveIns(LivePhysRegs &LiveRegs, const TargetRegisterInfo &TRI,
     LiveRegs.stepBackward(MI);
 
   for (unsigned Reg : LiveRegs) {
+    if (MRI.isReserved(Reg))
+      continue;
     // Skip the register if we are about to add one of its super registers.
     bool ContainsSuperReg = false;
     for (MCSuperRegIterator SReg(Reg, &TRI); SReg.isValid(); ++SReg) {
-      if (LiveRegs.contains(*SReg)) {
+      if (LiveRegs.contains(*SReg) && !MRI.isReserved(*SReg)) {
         ContainsSuperReg = true;
         break;
       }