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

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) {
+      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; }
-      
       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)) {
+  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

test/Transforms/GVN/condprop.ll

@@ -1,52 +0,0 @@
-; RUN: llvm-as < %s | opt -gvn | llvm-dis | grep {br i1 false}
-
-@a = external global i32		; <i32*> [#uses=7]
-
-define i32 @foo() nounwind {
-entry:
-	%0 = load i32* @a, align 4		; <i32> [#uses=1]
-	%1 = icmp eq i32 %0, 4		; <i1> [#uses=1]
-	br i1 %1, label %bb, label %bb1
-
-bb:		; preds = %entry
-	br label %bb8
-
-bb1:		; preds = %entry
-	%2 = load i32* @a, align 4		; <i32> [#uses=1]
-	%3 = icmp eq i32 %2, 5		; <i1> [#uses=1]
-	br i1 %3, label %bb2, label %bb3
-
-bb2:		; preds = %bb1
-	br label %bb8
-
-bb3:		; preds = %bb1
-	%4 = load i32* @a, align 4		; <i32> [#uses=1]
-	%5 = icmp eq i32 %4, 4		; <i1> [#uses=1]
-	br i1 %5, label %bb4, label %bb5
-
-bb4:		; preds = %bb3
-	%6 = load i32* @a, align 4		; <i32> [#uses=1]
-	%7 = add i32 %6, 5		; <i32> [#uses=1]
-	br label %bb8
-
-bb5:		; preds = %bb3
-	%8 = load i32* @a, align 4		; <i32> [#uses=1]
-	%9 = icmp eq i32 %8, 5		; <i1> [#uses=1]
-	br i1 %9, label %bb6, label %bb7
-
-bb6:		; preds = %bb5
-	%10 = load i32* @a, align 4		; <i32> [#uses=1]
-	%11 = add i32 %10, 4		; <i32> [#uses=1]
-	br label %bb8
-
-bb7:		; preds = %bb5
-	%12 = load i32* @a, align 4		; <i32> [#uses=1]
-	br label %bb8
-
-bb8:		; preds = %bb7, %bb6, %bb4, %bb2, %bb
-	%.0 = phi i32 [ %12, %bb7 ], [ %11, %bb6 ], [ %7, %bb4 ], [ 4, %bb2 ], [ 5, %bb ]		; <i32> [#uses=1]
-	br label %return
-
-return:		; preds = %bb8
-	ret i32 %.0
-}