vendor/llvm/llvm-trunk-r240225

1 files changed, 8 insertions, 31 deletions

diff --git a/lib/CodeGen/LiveVariables.cpp b/lib/CodeGen/LiveVariables.cpp
index 11deb813dde8..b355393e76f7 100644
--- a/lib/CodeGen/LiveVariables.cpp
+++ b/lib/CodeGen/LiveVariables.cpp
@@ -738,45 +738,22 @@ bool LiveVariables::VarInfo::isLiveIn(const MachineBasicBlock &MBB,
 bool LiveVariables::isLiveOut(unsigned Reg, const MachineBasicBlock &MBB) {
   LiveVariables::VarInfo &VI = getVarInfo(Reg);
 
+  SmallPtrSet<const MachineBasicBlock *, 8> Kills;
+  for (unsigned i = 0, e = VI.Kills.size(); i != e; ++i)
+    Kills.insert(VI.Kills[i]->getParent());
+
   // Loop over all of the successors of the basic block, checking to see if
   // the value is either live in the block, or if it is killed in the block.
-  SmallVector<MachineBasicBlock*, 8> OpSuccBlocks;
-  for (MachineBasicBlock::const_succ_iterator SI = MBB.succ_begin(),
-         E = MBB.succ_end(); SI != E; ++SI) {
-    MachineBasicBlock *SuccMBB = *SI;
-
+  for (const MachineBasicBlock *SuccMBB : MBB.successors()) {
     // Is it alive in this successor?
     unsigned SuccIdx = SuccMBB->getNumber();
     if (VI.AliveBlocks.test(SuccIdx))
       return true;
-    OpSuccBlocks.push_back(SuccMBB);
+    // Or is it live because there is a use in a successor that kills it?
+    if (Kills.count(SuccMBB))
+      return true;
   }
 
-  // Check to see if this value is live because there is a use in a successor
-  // that kills it.
-  switch (OpSuccBlocks.size()) {
-  case 1: {
-    MachineBasicBlock *SuccMBB = OpSuccBlocks[0];
-    for (unsigned i = 0, e = VI.Kills.size(); i != e; ++i)
-      if (VI.Kills[i]->getParent() == SuccMBB)
-        return true;
-    break;
-  }
-  case 2: {
-    MachineBasicBlock *SuccMBB1 = OpSuccBlocks[0], *SuccMBB2 = OpSuccBlocks[1];
-    for (unsigned i = 0, e = VI.Kills.size(); i != e; ++i)
-      if (VI.Kills[i]->getParent() == SuccMBB1 ||
-          VI.Kills[i]->getParent() == SuccMBB2)
-        return true;
-    break;
-  }
-  default:
-    std::sort(OpSuccBlocks.begin(), OpSuccBlocks.end());
-    for (unsigned i = 0, e = VI.Kills.size(); i != e; ++i)
-      if (std::binary_search(OpSuccBlocks.begin(), OpSuccBlocks.end(),
-                             VI.Kills[i]->getParent()))
-        return true;
-  }
   return false;
 }