[PATCH] LivePhysRegs: Add support to add pristine registers when populating with live-in/live-out registers.

[Matthias Braun]

This feature is necessary for the ARMLoadStoreOpt cleanup that I will submit next.

REPOSITORY
  rL LLVM

http://reviews.llvm.org/D10139

Files:
  include/llvm/CodeGen/LivePhysRegs.h
  lib/CodeGen/LivePhysRegs.cpp

Index: include/llvm/CodeGen/LivePhysRegs.h
===================================================================
--- include/llvm/CodeGen/LivePhysRegs.h
+++ include/llvm/CodeGen/LivePhysRegs.h
@@ -116,19 +116,15 @@
   void stepForward(const MachineInstr &MI,
         SmallVectorImpl<std::pair<unsigned, const MachineOperand*>> &Clobbers);
 
-  /// \brief Adds all live-in registers of basic block @p MBB.
-  void addLiveIns(const MachineBasicBlock *MBB) {
-    for (MachineBasicBlock::livein_iterator LI = MBB->livein_begin(),
-         LE = MBB->livein_end(); LI != LE; ++LI)
-      addReg(*LI);
-  }
-
-  /// \brief Adds all live-out registers of basic block @p MBB.
-  void addLiveOuts(const MachineBasicBlock *MBB) {
-    for (MachineBasicBlock::const_succ_iterator SI = MBB->succ_begin(),
-         SE = MBB->succ_end(); SI != SE; ++SI)
-      addLiveIns(*SI);
-  }
+  /// \brief Adds all live-in registers of basic block @p MBB; After prologue/
+  /// epilogue insertion \p AddPristines should be set to true to insert the
+  /// pristine registers.
+  void addLiveIns(const MachineBasicBlock *MBB, bool AddPristines = false);
+
+  /// \brief Adds all live-out registers of basic block @p MBB; After prologue/
+  /// epilogue insertion \p AddPristines should be set to true to insert the
+  /// pristine registers.
+  void addLiveOuts(const MachineBasicBlock *MBB, bool AddPristines = false);
 
   typedef SparseSet<unsigned>::const_iterator const_iterator;
   const_iterator begin() const { return LiveRegs.begin(); }
Index: lib/CodeGen/LivePhysRegs.cpp
===================================================================
--- lib/CodeGen/LivePhysRegs.cpp
+++ lib/CodeGen/LivePhysRegs.cpp
@@ -14,6 +14,8 @@
 //===----------------------------------------------------------------------===//
 
 #include "llvm/CodeGen/LivePhysRegs.h"
+#include "llvm/CodeGen/MachineFrameInfo.h"
+#include "llvm/CodeGen/MachineFunction.h"
 #include "llvm/CodeGen/MachineInstrBundle.h"
 #include "llvm/Support/Debug.h"
 #include "llvm/Support/raw_ostream.h"
@@ -123,3 +125,42 @@
   dbgs() << "  " << *this;
 #endif
 }
+
+/// Add live-in registers of basic block \p MBB to \p LiveRegs.
+static void addLiveIns(LivePhysRegs &LiveRegs, const MachineBasicBlock &MBB) {
+  for (unsigned Reg : make_range(MBB.livein_begin(), MBB.livein_end()))
+    LiveRegs.addReg(Reg);
+}
+
+/// 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 TargetRegisterInfo &TRI) {
+  const MachineFrameInfo &MFI = *MF.getFrameInfo();
+  if (!MFI.isCalleeSavedInfoValid())
+    return;
+
+  for (const MCPhysReg *CSR = TRI.getCalleeSavedRegs(&MF); CSR && *CSR; ++CSR)
+    LiveRegs.addReg(*CSR);
+  for (const CalleeSavedInfo &Info : MFI.getCalleeSavedInfo())
+    LiveRegs.removeReg(Info.getReg());
+}
+
+void LivePhysRegs::addLiveOuts(const MachineBasicBlock *MBB,
+                               bool AddPristines) {
+  if (AddPristines) {
+    const MachineFunction &MF = *MBB->getParent();
+    addPristines(*this, MF, *TRI);
+  }
+  for (const MachineBasicBlock *Succ : MBB->successors())
+    ::addLiveIns(*this, *Succ);
+}
+
+void LivePhysRegs::addLiveIns(const MachineBasicBlock *MBB,
+                              bool AddPristines) {
+  if (AddPristines) {
+    const MachineFunction &MF = *MBB->getParent();
+    addPristines(*this, MF, *TRI);
+  }
+  ::addLiveIns(*this, *MBB);
+}

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