This situation can occur:

[oota-llvm.git] / lib / CodeGen / SimpleRegisterCoalescing.h

diff --git a/lib/CodeGen/SimpleRegisterCoalescing.h b/lib/CodeGen/SimpleRegisterCoalescing.h
index 1c216203020e47d935ab52094b4f775b4edf35f8..3a65a9f4dd7095b373745d31a2a6cf13c91c52fd 100644 (file)
--- a/lib/CodeGen/SimpleRegisterCoalescing.h
+++ b/lib/CodeGen/SimpleRegisterCoalescing.h
@@ -83,7 +83,6 @@ namespace llvm {
     const TargetRegisterInfo* tri_;
     const TargetInstrInfo* tii_;
     LiveIntervals *li_;
-    LiveVariables *lv_;
     const MachineLoopInfo* loopInfo;
     
     BitVector allocatableRegs_;
@@ -166,9 +165,13 @@ namespace llvm {
     /// joins them and returns true.
     bool SimpleJoin(LiveInterval &LHS, LiveInterval &RHS);
     
-    /// Return true if the two specified registers belong to different
-    /// register classes.  The registers may be either phys or virt regs.
-    bool differingRegisterClasses(unsigned RegA, unsigned RegB) const;
+    /// Return true if the two specified registers belong to different register
+    /// classes.  The registers may be either phys or virt regs. In the
+    /// case where both registers are virtual registers, it would also returns
+    /// true by reference the RegB register class in SubRC if it is a subset of
+    /// RegA's register class.
+    bool differingRegisterClasses(unsigned RegA, unsigned RegB,
+                                  const TargetRegisterClass *&SubRC) const;
 
 
     /// AdjustCopiesBackFrom - We found a non-trivially-coalescable copy. If
@@ -190,9 +193,37 @@ namespace llvm {
     bool RemoveCopyByCommutingDef(LiveInterval &IntA, LiveInterval &IntB,
                                   MachineInstr *CopyMI);
 
-    /// isBackEdgeCopy - Returns true if CopyMI is a back edge copy.
+    /// TurnCopyIntoImpDef - If source of the specified copy is an implicit def,
+    /// turn the copy into an implicit def.
+    bool TurnCopyIntoImpDef(MachineBasicBlock::iterator &I,
+                            MachineBasicBlock *MBB,
+                            unsigned DstReg, unsigned SrcReg);
+
+    /// CanCoalesceWithImpDef - Returns true if the specified copy instruction
+    /// from an implicit def to another register can be coalesced away.
+    bool CanCoalesceWithImpDef(MachineInstr *CopyMI,
+                               LiveInterval &li, LiveInterval &ImpLi) const;
+
+    /// RemoveCopiesFromValNo - The specified value# is defined by an implicit
+    /// def and it is being removed. Turn all copies from this value# into
+    /// identity copies so they will be removed.
+    void RemoveCopiesFromValNo(LiveInterval &li, VNInfo *VNI);
+
+    /// isProfitableToCoalesceToSubRC - Given that register class of DstReg is
+    /// a subset of the register class of SrcReg, return true if it's profitable
+    /// to coalesce the two registers.
+    bool isProfitableToCoalesceToSubRC(unsigned SrcReg, unsigned DstReg,
+                                       MachineBasicBlock *MBB);
+
+    /// RangeIsDefinedByCopyFromReg - Return true if the specified live range of
+    /// the specified live interval is defined by a copy from the specified
+    /// register.
+    bool RangeIsDefinedByCopyFromReg(LiveInterval &li, LiveRange *LR,
+                                     unsigned Reg);
+
+    /// isBackEdgeCopy - Return true if CopyMI is a back edge copy.
     ///
-    bool isBackEdgeCopy(MachineInstr *CopyMI, unsigned DstReg);
+    bool isBackEdgeCopy(MachineInstr *CopyMI, unsigned DstReg) const;
 
     /// UpdateRegDefsUses - Replace all defs and uses of SrcReg to DstReg and
     /// update the subregister number if it is not zero. If DstReg is a
@@ -201,6 +232,24 @@ namespace llvm {
     /// subregister.
     void UpdateRegDefsUses(unsigned SrcReg, unsigned DstReg, unsigned SubIdx);
 
+    /// RemoveDeadImpDef - Remove implicit_def instructions which are
+    /// "re-defining" registers due to insert_subreg coalescing. e.g.
+    void RemoveDeadImpDef(unsigned Reg, LiveInterval &LI);
+
+    /// RemoveUnnecessaryKills - Remove kill markers that are no longer accurate
+    /// due to live range lengthening as the result of coalescing.
+    void RemoveUnnecessaryKills(unsigned Reg, LiveInterval &LI);
+
+    /// ShortenDeadCopyLiveRange - Shorten a live range defined by a dead copy.
+    /// Return true if live interval is removed.
+    bool ShortenDeadCopyLiveRange(LiveInterval &li, MachineInstr *CopyMI);
+
+    /// ShortenDeadCopyLiveRange - Shorten a live range as it's artificially
+    /// extended by a dead copy. Mark the last use (if any) of the val# as kill
+    /// as ends the live range there. If there isn't another use, then this
+    /// live range is dead. Return true if live interval is removed.
+    bool ShortenDeadCopySrcLiveRange(LiveInterval &li, MachineInstr *CopyMI);
+
     /// lastRegisterUse - Returns the last use of the specific register between
     /// cycles Start and End or NULL if there are no uses.
     MachineOperand *lastRegisterUse(unsigned Start, unsigned End, unsigned Reg,