- Changes how function livein's are handled, they now have a start index of 0.

- When coalescing a copy MI, if its destination is "dead", propagate the
  property to the source MI's destination if there are no intervening uses.
- Detect dead function live-in's and remove them.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@34383 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 16 insertions, 2 deletions

diff --git a/include/llvm/CodeGen/LiveIntervalAnalysis.h b/include/llvm/CodeGen/LiveIntervalAnalysis.h
index 362b3545fb..ef48453b10 100644
--- a/include/llvm/CodeGen/LiveIntervalAnalysis.h
+++ b/include/llvm/CodeGen/LiveIntervalAnalysis.h
@@ -118,6 +118,11 @@ namespace llvm {
       return I->second;
     }
 
+    bool hasInterval(unsigned reg) const {
+      Reg2IntervalMap::const_iterator I = r2iMap_.find(reg);
+      return I != r2iMap_.end();
+    }
+
     /// getMBBStartIdx - Return the base index of the first instruction in the
     /// specified MachineBasicBlock.
     unsigned getMBBStartIdx(MachineBasicBlock *MBB) const {
@@ -189,6 +194,7 @@ namespace llvm {
     /// copies that cannot yet be coallesced into the "TryAgain" list.
     void CopyCoallesceInMBB(MachineBasicBlock *MBB,
                             std::vector<CopyRec> &TryAgain);
+
     /// JoinCopy - Attempt to join intervals corresponding to SrcReg/DstReg,
     /// which are the src/dst of the copy instruction CopyMI.  This returns true
     /// if the copy was successfully coallesced away, or if it is never possible
@@ -233,6 +239,9 @@ namespace llvm {
                                    LiveInterval &interval,
                                    unsigned SrcReg);
 
+    /// handleLiveInRegister - Create interval for a livein register.
+    void handleLiveInRegister(MachineBasicBlock* mbb, LiveInterval &interval);
+
     /// 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;
@@ -241,11 +250,16 @@ namespace llvm {
     bool AdjustCopiesBackFrom(LiveInterval &IntA, LiveInterval &IntB,
                               MachineInstr *CopyMI);
 
-    bool overlapsAliases(const LiveInterval *lhs,
-                         const LiveInterval *rhs) const;
+    /// hasRegisterUse - Returns true if there is any use of the specific
+    /// reg between indexes Start and End.
+    bool hasRegisterUse(unsigned Reg, unsigned Start, unsigned End);
 
     static LiveInterval createInterval(unsigned Reg);
 
+    void removeInterval(unsigned Reg) {
+      r2iMap_.erase(Reg);
+    }
+
     LiveInterval &getOrCreateInterval(unsigned reg) {
       Reg2IntervalMap::iterator I = r2iMap_.find(reg);
       if (I == r2iMap_.end())