Revert r68172. It caused regressions in

  Applications/Burg/burg
  Applications/ClamAV/clamscan
and many other tests.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@68211 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 10 insertions, 38 deletions

diff --git a/lib/Transforms/Scalar/GVN.cpp b/lib/Transforms/Scalar/GVN.cpp
index 5ce51c7..e537986 100644
--- a/lib/Transforms/Scalar/GVN.cpp
+++ b/lib/Transforms/Scalar/GVN.cpp
@@ -121,7 +121,6 @@ namespace {
       AliasAnalysis* AA;
       MemoryDependenceAnalysis* MD;
       DominatorTree* DT;
-      uint32_t true_vn, false_vn;
   
       uint32_t nextValueNumber;
     
@@ -139,14 +138,7 @@ namespace {
       Expression create_expression(CallInst* C);
       Expression create_expression(Constant* C);
     public:
-      ValueTable() : nextValueNumber(1) {
-        true_vn = lookup_or_add(ConstantInt::getTrue());
-        false_vn = lookup_or_add(ConstantInt::getFalse());
-      }
-      
-      uint32_t getTrueVN() { return true_vn; }
-      uint32_t getFalseVN() { return false_vn; }
-      
+      ValueTable() : nextValueNumber(1) { }
       uint32_t lookup_or_add(Value* V);
       uint32_t lookup(Value* V) const;
       void add(Value* V, uint32_t num);
@@ -1302,27 +1294,9 @@ bool GVN::processInstruction(Instruction *I,
   uint32_t nextNum = VN.getNextUnusedValueNumber();
   unsigned num = VN.lookup_or_add(I);
   
-  if (BranchInst* BI = dyn_cast<BranchInst>(I)) {
-    localAvail[I->getParent()]->table.insert(std::make_pair(num, I));
-    
-    if (!BI->isConditional() || isa<Constant>(BI->getCondition()))
-      return false;
-    
-    Value* branchCond = BI->getCondition();
-    uint32_t condVN = VN.lookup_or_add(branchCond);
-    
-    BasicBlock* trueSucc = BI->getSuccessor(0);
-    BasicBlock* falseSucc = BI->getSuccessor(1);
-    
-    localAvail[trueSucc]->table.insert(std::make_pair(condVN,
-                                                      ConstantInt::getTrue()));
-    localAvail[falseSucc]->table.insert(std::make_pair(condVN,
-                                                      ConstantInt::getFalse()));
-    return false;
-    
   // Allocations are always uniquely numbered, so we can save time and memory
-  // by fast failing them.  
-  } else if (isa<AllocationInst>(I) || isa<TerminatorInst>(I)) {
+  // by fast failing them.
+  if (isa<AllocationInst>(I) || isa<TerminatorInst>(I)) {
     localAvail[I->getParent()]->table.insert(std::make_pair(num, I));
     return false;
   }
@@ -1431,11 +1405,18 @@ bool GVN::runOnFunction(Function& F) {
 
 
 bool GVN::processBlock(BasicBlock* BB) {
+  DomTreeNode* DTN = DT->getNode(BB);
   // FIXME: Kill off toErase by doing erasing eagerly in a helper function (and
   // incrementing BI before processing an instruction).
   SmallVector<Instruction*, 8> toErase;
   bool changed_function = false;
   
+  if (DTN->getIDom())
+    localAvail[BB] =
+                  new ValueNumberScope(localAvail[DTN->getIDom()->getBlock()]);
+  else
+    localAvail[BB] = new ValueNumberScope(0);
+  
   for (BasicBlock::iterator BI = BB->begin(), BE = BB->end();
        BI != BE;) {
     changed_function |= processInstruction(BI, toErase);
@@ -1626,15 +1607,6 @@ bool GVN::performPRE(Function& F) {
 bool GVN::iterateOnFunction(Function &F) {
   cleanupGlobalSets();
 
-  for (df_iterator<DomTreeNode*> DI = df_begin(DT->getRootNode()),
-       DE = df_end(DT->getRootNode()); DI != DE; ++DI) {
-    if (DI->getIDom())
-      localAvail[DI->getBlock()] =
-                   new ValueNumberScope(localAvail[DI->getIDom()->getBlock()]);
-    else
-      localAvail[DI->getBlock()] = new ValueNumberScope(0);
-  }
-
   // Top-down walk of the dominator tree
   bool changed = false;
 #if 0