Remove unnecessary isKill properties if a live range has been lengthened due to coale...

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@34503 91177308-0d34-0410-b5e6-96231b3b80d8

diff --git a/include/llvm/CodeGen/LiveIntervalAnalysis.h b/include/llvm/CodeGen/LiveIntervalAnalysis.h
index 69103a3..dc72807 100644 (file)
--- a/include/llvm/CodeGen/LiveIntervalAnalysis.h
+++ b/include/llvm/CodeGen/LiveIntervalAnalysis.h
@@ -172,6 +172,13 @@ namespace llvm {
     }
 
   private:
+    /// isRemoved - returns true if the specified machine instr has been
+    /// removed.
+    bool isRemoved(MachineInstr* instr) const {
+      Mi2IndexMap::const_iterator it = mi2iMap_.find(instr);
+      return it == mi2iMap_.end();
+    }
+
     /// RemoveMachineInstrFromMaps - This marks the specified machine instr as
     /// deleted.
     void RemoveMachineInstrFromMaps(MachineInstr *MI) {
@@ -256,6 +263,10 @@ namespace llvm {
     /// reg between indexes Start and End.
     bool hasRegisterUse(unsigned Reg, unsigned Start, unsigned End);
 
+    /// unsetRegisterKill - Unset IsKill property of all uses of specific
+    /// register of the specific instruction.
+    void unsetRegisterKill(MachineInstr *MI, unsigned Reg);
+
     static LiveInterval createInterval(unsigned Reg);
 
     void removeInterval(unsigned Reg) {

diff --git a/lib/CodeGen/LiveIntervalAnalysis.cpp b/lib/CodeGen/LiveIntervalAnalysis.cpp
index 29c095a..f03830a 100644 (file)
--- a/lib/CodeGen/LiveIntervalAnalysis.cpp
+++ b/lib/CodeGen/LiveIntervalAnalysis.cpp
@@ -959,10 +959,22 @@ bool LiveIntervals::JoinCopy(MachineInstr *CopyMI,
 
   DOUT << "\n\t\tJoined.  Result = "; DestInt.print(DOUT, mri_);
   DOUT << "\n";
-  
+
   // If the intervals were swapped by Join, swap them back so that the register
   // mapping (in the r2i map) is correct.
   if (Swapped) SrcInt.swap(DestInt);
+
+  // Live range has been lengthened due to colaescing, eliminate the
+  // unnecessary kills at the end of the source live ranges.
+  LiveVariables::VarInfo& vi = lv_->getVarInfo(repSrcReg);
+  for (unsigned i = 0, e = vi.Kills.size(); i != e; ++i) {
+    MachineInstr *Kill = vi.Kills[i];
+    if (Kill == CopyMI || isRemoved(Kill))
+      continue;
+    if (DestInt.liveAt(getInstructionIndex(Kill) + InstrSlots::NUM))
+      unsetRegisterKill(Kill, repSrcReg);
+  }
+
   removeInterval(repSrcReg);
   r2rMap_[repSrcReg] = repDstReg;
 
@@ -1471,6 +1483,17 @@ LiveIntervals::hasRegisterUse(unsigned Reg, unsigned Start, unsigned End) {
   return false;
 }
 
+/// unsetRegisterKill - Unset IsKill property of all uses of specific register
+/// of the specific instruction.
+void LiveIntervals::unsetRegisterKill(MachineInstr *MI, unsigned Reg) {
+  for (unsigned i = 0, e = MI->getNumOperands(); i != e; ++i) {
+    MachineOperand &MO = MI->getOperand(i);
+    if (MO.isReg() && MO.isUse() && MO.isKill() && MO.getReg() &&
+        mri_->regsOverlap(rep(MO.getReg()), Reg))
+      MO.unsetIsKill();
+  }
+}
+
 LiveInterval LiveIntervals::createInterval(unsigned reg) {
   float Weight = MRegisterInfo::isPhysicalRegister(reg) ?
                        HUGE_VALF : 0.0F;