This situation can occur:

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

diff --git a/lib/CodeGen/SimpleRegisterCoalescing.h b/lib/CodeGen/SimpleRegisterCoalescing.h
index fa63159d1c86b0c4a1cf2d23ac7f1c67458a67b7..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
@@ -206,6 +209,12 @@ namespace llvm {
     /// 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.
@@ -232,14 +241,14 @@ namespace llvm {
     void RemoveUnnecessaryKills(unsigned Reg, LiveInterval &LI);
 
     /// ShortenDeadCopyLiveRange - Shorten a live range defined by a dead copy.
-    ///
-    void ShortenDeadCopyLiveRange(LiveInterval &li, MachineInstr *CopyMI);
+    /// 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.
-    void ShortenDeadCopySrcLiveRange(LiveInterval &li, MachineInstr *CopyMI);
+    /// 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.