Clear kill flags while computing live ranges.

Kill flags are difficult to maintain, and liveness queries are better
handled by live intervals.

Kill flags are reinserted after register allocation by addKillFlags().

llvm-svn: 163334

1 files changed, 5 insertions, 1 deletions

diff --git a/llvm/lib/CodeGen/LiveRangeCalc.cpp b/llvm/lib/CodeGen/LiveRangeCalc.cpp
index d828f25932e..c3ff4f1b6d2 100644
--- a/llvm/lib/CodeGen/LiveRangeCalc.cpp
+++ b/llvm/lib/CodeGen/LiveRangeCalc.cpp
@@ -65,7 +65,11 @@ void LiveRangeCalc::extendToUses(LiveInterval *LI, unsigned Reg) {
   // Visit all operands that read Reg. This may include partial defs.
   for (MachineRegisterInfo::reg_nodbg_iterator I = MRI->reg_nodbg_begin(Reg),
        E = MRI->reg_nodbg_end(); I != E; ++I) {
-    const MachineOperand &MO = I.getOperand();
+    MachineOperand &MO = I.getOperand();
+    // Clear all kill flags. They will be reinserted after register allocation
+    // by LiveIntervalAnalysis::addKillFlags().
+    if (MO.isUse())
+      MO.setIsKill(false);
     if (!MO.readsReg())
       continue;
     // MI is reading Reg. We may have visited MI before if it happens to be