Fix PR17952.

  The symptom is that an assertion is triggered. The assertion was added by
me to detect the situation when value is propagated from dead blocks.
(We can certainly get rid of assertion; it is safe to do so, because propagating
 value from dead block to alive join node is certainly ok.)

  The root cause of this bug is : edge-splitting is conducted on the fly,
the edge being split could be a dead edge, therefore the block that 
split the critial edge needs to be flagged "dead" as well.

  There are 3 ways to fix this bug:
  1) Get rid of the assertion as I mentioned eariler 
  2) When an dead edge is split, flag the inserted block "dead".
  3) proactively split the critical edges connecting dead and live blocks when
     new dead blocks are revealed.

  This fix go for 3) with additional 2 LOC.

  Testing case was added by Rafael the other day.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@194424 91177308-0d34-0410-b5e6-96231b3b80d8

9 files changed, 396 insertions, 28 deletions

diff --git a/lib/Transforms/Scalar/GVN.cpp b/lib/Transforms/Scalar/GVN.cpp
index 957c123034..d353765b42 100644
--- a/lib/Transforms/Scalar/GVN.cpp
+++ b/lib/Transforms/Scalar/GVN.cpp
@@ -21,6 +21,7 @@
 #include "llvm/ADT/DepthFirstIterator.h"
 #include "llvm/ADT/Hashing.h"
 #include "llvm/ADT/SmallPtrSet.h"
+#include "llvm/ADT/SetVector.h"
 #include "llvm/ADT/Statistic.h"
 #include "llvm/Analysis/AliasAnalysis.h"
 #include "llvm/Analysis/CFG.h"
@@ -507,7 +508,9 @@ namespace {
     enum ValType {
       SimpleVal,  // A simple offsetted value that is accessed.
       LoadVal,    // A value produced by a load.
-      MemIntrin   // A memory intrinsic which is loaded from.
+      MemIntrin,  // A memory intrinsic which is loaded from.
+      UndefVal    // A UndefValue representing a value from dead block (which
+                  // is not yet physically removed from the CFG). 
     };
   
     /// V - The value that is live out of the block.
@@ -545,10 +548,20 @@ namespace {
       Res.Offset = Offset;
       return Res;
     }
-  
+
+    static AvailableValueInBlock getUndef(BasicBlock *BB) {
+      AvailableValueInBlock Res;
+      Res.BB = BB;
+      Res.Val.setPointer(0);
+      Res.Val.setInt(UndefVal);
+      Res.Offset = 0;
+      return Res;
+    }
+
     bool isSimpleValue() const { return Val.getInt() == SimpleVal; }
     bool isCoercedLoadValue() const { return Val.getInt() == LoadVal; }
     bool isMemIntrinValue() const { return Val.getInt() == MemIntrin; }
+    bool isUndefValue() const { return Val.getInt() == UndefVal; }
   
     Value *getSimpleValue() const {
       assert(isSimpleValue() && "Wrong accessor");
@@ -576,6 +589,7 @@ namespace {
     DominatorTree *DT;
     const DataLayout *TD;
     const TargetLibraryInfo *TLI;
+    SetVector<BasicBlock *> DeadBlocks;
 
     ValueTable VN;
 
@@ -698,6 +712,9 @@ namespace {
     unsigned replaceAllDominatedUsesWith(Value *From, Value *To,
                                          const BasicBlockEdge &Root);
     bool propagateEquality(Value *LHS, Value *RHS, const BasicBlockEdge &Root);
+    bool processFoldableCondBr(BranchInst *BI);
+    void addDeadBlock(BasicBlock *BB);
+    void assignValNumForDeadCode();
   };
 
   char GVN::ID = 0;
@@ -1255,8 +1272,10 @@ static Value *ConstructSSAForLoadSet(LoadInst *LI,
   // just use the dominating value directly.
   if (ValuesPerBlock.size() == 1 &&
       gvn.getDominatorTree().properlyDominates(ValuesPerBlock[0].BB,
-                                               LI->getParent()))
+                                               LI->getParent())) {
+    assert(!ValuesPerBlock[0].isUndefValue() && "Dead BB dominate this block");
     return ValuesPerBlock[0].MaterializeAdjustedValue(LI->getType(), gvn);
+  }
 
   // Otherwise, we have to construct SSA form.
   SmallVector<PHINode*, 8> NewPHIs;
@@ -1326,7 +1345,7 @@ Value *AvailableValueInBlock::MaterializeAdjustedValue(Type *LoadTy, GVN &gvn) c
                    << *getCoercedLoadValue() << '\n'
                    << *Res << '\n' << "\n\n\n");
     }
-  } else {
+  } else if (isMemIntrinValue()) {
     const DataLayout *TD = gvn.getDataLayout();
     assert(TD && "Need target data to handle type mismatch case");
     Res = GetMemInstValueForLoad(getMemIntrinValue(), Offset,
@@ -1334,6 +1353,10 @@ Value *AvailableValueInBlock::MaterializeAdjustedValue(Type *LoadTy, GVN &gvn) c
     DEBUG(dbgs() << "GVN COERCED NONLOCAL MEM INTRIN:\nOffset: " << Offset
                  << "  " << *getMemIntrinValue() << '\n'
                  << *Res << '\n' << "\n\n\n");
+  } else {
+    assert(isUndefValue() && "Should be UndefVal");
+    DEBUG(dbgs() << "GVN COERCED NONLOCAL Undef:\n";);
+    return UndefValue::get(LoadTy);
   }
   return Res;
 }
@@ -1357,6 +1380,13 @@ void GVN::AnalyzeLoadAvailability(LoadInst *LI, LoadDepVect &Deps,
     BasicBlock *DepBB = Deps[i].getBB();
     MemDepResult DepInfo = Deps[i].getResult();
 
+    if (DeadBlocks.count(DepBB)) {
+      // Dead dependent mem-op disguise as a load evaluating the same value
+      // as the load in question.
+      ValuesPerBlock.push_back(AvailableValueInBlock::getUndef(DepBB));
+      continue;
+    }
+
     if (!DepInfo.isDef() && !DepInfo.isClobber()) {
       UnavailableBlocks.push_back(DepBB);
       continue;
@@ -2193,11 +2223,13 @@ bool GVN::processInstruction(Instruction *I) {
   // For conditional branches, we can perform simple conditional propagation on
   // the condition value itself.
   if (BranchInst *BI = dyn_cast<BranchInst>(I)) {
-    if (!BI->isConditional() || isa<Constant>(BI->getCondition()))
+    if (!BI->isConditional())
       return false;
 
-    Value *BranchCond = BI->getCondition();
+    if (isa<Constant>(BI->getCondition()))
+      return processFoldableCondBr(BI);
 
+    Value *BranchCond = BI->getCondition();
     BasicBlock *TrueSucc = BI->getSuccessor(0);
     BasicBlock *FalseSucc = BI->getSuccessor(1);
     // Avoid multiple edges early.
@@ -2314,6 +2346,9 @@ bool GVN::runOnFunction(Function& F) {
   }
 
   if (EnablePRE) {
+    // Fabricate val-num for dead-code in order to suppress assertion in
+    // performPRE().
+    assignValNumForDeadCode();
     bool PREChanged = true;
     while (PREChanged) {
       PREChanged = performPRE(F);
@@ -2327,6 +2362,9 @@ bool GVN::runOnFunction(Function& F) {
   // Actually, when this happens, we should just fully integrate PRE into GVN.
 
   cleanupGlobalSets();
+  // Do not cleanup DeadBlocks in cleanupGlobalSets() as it's called for each
+  // iteration. 
+  DeadBlocks.clear();
 
   return Changed;
 }
@@ -2337,6 +2375,9 @@ bool GVN::processBlock(BasicBlock *BB) {
   // (and incrementing BI before processing an instruction).
   assert(InstrsToErase.empty() &&
          "We expect InstrsToErase to be empty across iterations");
+  if (DeadBlocks.count(BB))
+    return false;
+
   bool ChangedFunction = false;
 
   for (BasicBlock::iterator BI = BB->begin(), BE = BB->end();
@@ -2630,3 +2671,131 @@ void GVN::verifyRemoved(const Instruction *Inst) const {
     }
   }
 }
+
+// BB is declared dead, which implied other blocks become dead as well. This
+// function is to add all these blocks to "DeadBlocks". For the dead blocks'
+// live successors, update their phi nodes by replacing the operands
+// corresponding to dead blocks with UndefVal.
+//
+void GVN::addDeadBlock(BasicBlock *BB) {
+  SmallVector<BasicBlock *, 4> NewDead;
+  SmallSetVector<BasicBlock *, 4> DF;
+
+  NewDead.push_back(BB);
+  while (!NewDead.empty()) {
+    BasicBlock *D = NewDead.pop_back_val();
+    if (DeadBlocks.count(D))
+      continue;
+
+    // All blocks dominated by D are dead.
+    SmallVector<BasicBlock *, 8> Dom;
+    DT->getDescendants(D, Dom);
+    DeadBlocks.insert(Dom.begin(), Dom.end());
+    
+    // Figure out the dominance-frontier(D).
+    for (SmallVectorImpl<BasicBlock *>::iterator I = Dom.begin(),
+           E = Dom.end(); I != E; I++) {
+      BasicBlock *B = *I;
+      for (succ_iterator SI = succ_begin(B), SE = succ_end(B); SI != SE; SI++) {
+        BasicBlock *S = *SI;
+        if (DeadBlocks.count(S))
+          continue;
+
+        bool AllPredDead = true;
+        for (pred_iterator PI = pred_begin(S), PE = pred_end(S); PI != PE; PI++)
+          if (!DeadBlocks.count(*PI)) {
+            AllPredDead = false;
+            break;
+          }
+
+        if (!AllPredDead) {
+          // S could be proved dead later on. That is why we don't update phi
+          // operands at this moment.
+          DF.insert(S);
+        } else {
+          // While S is not dominated by D, it is dead by now. This could take
+          // place if S already have a dead predecessor before D is declared
+          // dead.
+          NewDead.push_back(S);
+        }
+      }
+    }
+  }
+
+  // For the dead blocks' live successors, update their phi nodes by replacing
+  // the operands corresponding to dead blocks with UndefVal.
+  for(SmallSetVector<BasicBlock *, 4>::iterator I = DF.begin(), E = DF.end();
+        I != E; I++) {
+    BasicBlock *B = *I;
+    if (DeadBlocks.count(B))
+      continue;
+
+    for (pred_iterator PI = pred_begin(B), PE = pred_end(B); PI != PE; PI++) {
+      BasicBlock *P = *PI;
+
+      if (!DeadBlocks.count(P))
+        continue;
+
+      if (isCriticalEdge(P->getTerminator(), GetSuccessorNumber(P, B))) {
+        if (BasicBlock *S = splitCriticalEdges(P, B))
+          DeadBlocks.insert(P = S);
+      }
+
+      for (BasicBlock::iterator II = B->begin(); isa<PHINode>(II); ++II) {
+        PHINode &Phi = cast<PHINode>(*II);
+        Phi.setIncomingValue(Phi.getBasicBlockIndex(P),
+                             UndefValue::get(Phi.getType()));
+      }
+    }
+  }
+}
+
+// If the given branch is recognized as a foldable branch (i.e. conditional
+// branch with constant condition), it will perform following analyses and
+// transformation.
+//  1) If the dead out-coming edge is a critical-edge, split it. Let 
+//     R be the target of the dead out-coming edge.
+//  1) Identify the set of dead blocks implied by the branch's dead outcoming
+//     edge. The result of this step will be {X| X is dominated by R}
+//  2) Identify those blocks which haves at least one dead prodecessor. The
+//     result of this step will be dominance-frontier(R).
+//  3) Update the PHIs in DF(R) by replacing the operands corresponding to 
+//     dead blocks with "UndefVal" in an hope these PHIs will optimized away.
+//
+// Return true iff *NEW* dead code are found.
+bool GVN::processFoldableCondBr(BranchInst *BI) {
+  if (!BI || BI->isUnconditional())
+    return false;
+
+  ConstantInt *Cond = dyn_cast<ConstantInt>(BI->getCondition());
+  if (!Cond)
+    return false;
+
+  BasicBlock *DeadRoot = Cond->getZExtValue() ? 
+                         BI->getSuccessor(1) : BI->getSuccessor(0);
+  if (DeadBlocks.count(DeadRoot))
+    return false;
+
+  if (!DeadRoot->getSinglePredecessor())
+    DeadRoot = splitCriticalEdges(BI->getParent(), DeadRoot);
+
+  addDeadBlock(DeadRoot);
+  return true;
+}
+
+// performPRE() will trigger assert if it come across an instruciton without
+// associated val-num. As it normally has far more live instructions than dead
+// instructions, it makes more sense just to "fabricate" a val-number for the
+// dead code than checking if instruction involved is dead or not.
+void GVN::assignValNumForDeadCode() {
+  for (SetVector<BasicBlock *>::iterator I = DeadBlocks.begin(),
+        E = DeadBlocks.end(); I != E; I++) {
+    BasicBlock *BB = *I;
+    for (BasicBlock::iterator II = BB->begin(), EE = BB->end();
+          II != EE; II++) {
+      Instruction *Inst = &*II;
+      unsigned ValNum = VN.lookup_or_add(Inst);
+      addToLeaderTable(ValNum, Inst, BB);
+    }
+  }
+}
diff --git a/test/Transforms/GVN/2007-07-26-InterlockingLoops.ll b/test/Transforms/GVN/2007-07-26-InterlockingLoops.ll
index a1cc0083f1..5a15f0e43a 100644
--- a/test/Transforms/GVN/2007-07-26-InterlockingLoops.ll
+++ b/test/Transforms/GVN/2007-07-26-InterlockingLoops.ll
@@ -2,7 +2,7 @@
 
 @last = external global [65 x i32*]
 
-define i32 @NextRootMove(i32 %wtm) {
+define i32 @NextRootMove(i32 %wtm, i32 %x, i32 %y, i32 %z) {
 entry:
         %A = alloca i32*
 	%tmp17618 = load i32** getelementptr ([65 x i32*]* @last, i32 0, i32 1), align 4
@@ -15,12 +15,14 @@ entry:
 	br label %cond_true116
 
 cond_true116:
-	br i1 false, label %cond_true128, label %cond_true145
+   %cmp = icmp eq i32 %x, %y
+	br i1 %cmp, label %cond_true128, label %cond_true145
 
 cond_true128:
 	%tmp17625 = load i32** getelementptr ([65 x i32*]* @last, i32 0, i32 1), align 4
         store i32* %tmp17625, i32** %A
-	br i1 false, label %bb98.backedge, label %return.loopexit
+   %cmp1 = icmp eq i32 %x, %z
+	br i1 %cmp1 , label %bb98.backedge, label %return.loopexit
 
 bb98.backedge:
 	br label %cond_true116
diff --git a/test/Transforms/GVN/2008-07-02-Unreachable.ll b/test/Transforms/GVN/2008-07-02-Unreachable.ll
index 4f07868a1c..ce83fa4e4b 100644
--- a/test/Transforms/GVN/2008-07-02-Unreachable.ll
+++ b/test/Transforms/GVN/2008-07-02-Unreachable.ll
@@ -3,10 +3,11 @@
 
 @g_3 = external global i8		; <i8*> [#uses=2]
 
-define i8 @func_1() nounwind  {
+define i8 @func_1(i32 %x, i32 %y) nounwind  {
 entry:
   %A = alloca i8
-	br i1 false, label %ifelse, label %ifthen
+    %cmp = icmp eq i32 %x, %y
+	br i1 %cmp, label %ifelse, label %ifthen
 
 ifthen:		; preds = %entry
 	br label %ifend
@@ -14,9 +15,6 @@ ifthen:		; preds = %entry
 ifelse:		; preds = %entry
 	%tmp3 = load i8* @g_3		; <i8> [#uses=0]
         store i8 %tmp3, i8* %A
-	br label %forcond.thread
-
-forcond.thread:		; preds = %ifelse
 	br label %afterfor
 
 forcond:		; preds = %forinc
diff --git a/test/Transforms/GVN/cond_br.ll b/test/Transforms/GVN/cond_br.ll
new file mode 100644
index 0000000000..918e7d41f1
--- /dev/null
+++ b/test/Transforms/GVN/cond_br.ll
@@ -0,0 +1,55 @@
+; RUN: opt -basicaa -gvn -S < %s | FileCheck %s
+@y = external global i32
+@z = external global i32
+
+; Function Attrs: nounwind ssp uwtable
+define void @foo(i32 %x) {
+; CHECK: @foo(i32 %x)
+; CHECK: %.pre = load i32* @y
+; CHECK: call void @bar(i32 %.pre)
+
+  %t = sub i32 %x, %x
+  %.pre = load i32* @y, align 4
+  %cmp = icmp sgt i32 %t, 2
+  br i1 %cmp, label %if.then, label %entry.if.end_crit_edge
+
+entry.if.end_crit_edge:                           ; preds = %entry
+  br label %if.end
+
+if.then:                                          ; preds = %entry
+  %add = add nsw i32 %x, 3
+  store i32 %add, i32* @y, align 4
+  br label %if.end
+
+if.end:                                           ; preds = %entry.if.end_crit_edge, %if.then
+  %1 = phi i32 [ %.pre, %entry.if.end_crit_edge ], [ %add, %if.then ]
+  tail call void @bar(i32 %1)
+  ret void
+}
+
+define void @foo2(i32 %x) {
+; CHECK: @foo2(i32 %x)
+; CHECK: %.pre = load i32* @y
+; CHECK: tail call void @bar(i32 %.pre)
+entry:
+  %t = sub i32 %x, %x
+  %.pre = load i32* @y, align 4
+  %cmp = icmp sgt i32 %t, 2
+  br i1 %cmp, label %if.then, label %if.else
+
+if.then:                                          ; preds = %entry
+  %add = add nsw i32 %x, 3
+  store i32 %add, i32* @y, align 4
+  br label %if.end
+
+if.else:                                          ; preds = %entry
+  store i32 1, i32* @z, align 4
+  br label %if.end
+
+if.end:                                           ; preds = %if.else, %if.then
+  %0 = phi i32 [ %.pre, %if.else ], [ %add, %if.then ]
+  tail call void @bar(i32 %0)
+  ret void
+}
+
+declare void @bar(i32)
diff --git a/test/Transforms/GVN/cond_br2.ll b/test/Transforms/GVN/cond_br2.ll
new file mode 100644
index 0000000000..27e6f75de2
--- /dev/null
+++ b/test/Transforms/GVN/cond_br2.ll
@@ -0,0 +1,140 @@
+; RUN: opt -basicaa -gvn -S < %s | FileCheck %s
+target datalayout = "e-p:64:64:64-i1:8:8-i8:8:8-i16:16:16-i32:32:32-i64:64:64-f32:32:32-f64:64:64-v64:64:64-v128:128:128-a0:0:64-s0:64:64-f80:128:128-n8:16:32:64-S128"
+
+%"class.llvm::SmallVector" = type { %"class.llvm::SmallVectorImpl", [1 x %"union.llvm::SmallVectorBase::U"] }
+%"class.llvm::SmallVectorImpl" = type { %"class.llvm::SmallVectorTemplateBase" }
+%"class.llvm::SmallVectorTemplateBase" = type { %"class.llvm::SmallVectorTemplateCommon" }
+%"class.llvm::SmallVectorTemplateCommon" = type { %"class.llvm::SmallVectorBase" }
+%"class.llvm::SmallVectorBase" = type { i8*, i8*, i8*, %"union.llvm::SmallVectorBase::U" }
+%"union.llvm::SmallVectorBase::U" = type { x86_fp80 }
+
+; Function Attrs: ssp uwtable
+define void @_Z4testv() #0 {
+; CHECK: @_Z4testv()
+; CHECK: invoke.cont:
+; CHECK: br i1 true, label %new.notnull.i11, label %if.end.i14
+; CHECK: Retry.i10:
+
+entry:
+  %sv = alloca %"class.llvm::SmallVector", align 16
+  %0 = bitcast %"class.llvm::SmallVector"* %sv to i8*
+  call void @llvm.lifetime.start(i64 64, i8* %0) #1
+  %BeginX.i.i.i.i.i.i = getelementptr inbounds %"class.llvm::SmallVector"* %sv, i64 0, i32 0, i32 0, i32 0, i32 0, i32 0
+  %FirstEl.i.i.i.i.i.i = getelementptr inbounds %"class.llvm::SmallVector"* %sv, i64 0, i32 0, i32 0, i32 0, i32 0, i32 3
+  %1 = bitcast %"union.llvm::SmallVectorBase::U"* %FirstEl.i.i.i.i.i.i to i8*
+  store i8* %1, i8** %BeginX.i.i.i.i.i.i, align 16, !tbaa !4
+  %EndX.i.i.i.i.i.i = getelementptr inbounds %"class.llvm::SmallVector"* %sv, i64 0, i32 0, i32 0, i32 0, i32 0, i32 1
+  store i8* %1, i8** %EndX.i.i.i.i.i.i, align 8, !tbaa !4
+  %CapacityX.i.i.i.i.i.i = getelementptr inbounds %"class.llvm::SmallVector"* %sv, i64 0, i32 0, i32 0, i32 0, i32 0, i32 2
+  %add.ptr.i.i.i.i2.i.i = getelementptr inbounds %"union.llvm::SmallVectorBase::U"* %FirstEl.i.i.i.i.i.i, i64 2
+  %add.ptr.i.i.i.i.i.i = bitcast %"union.llvm::SmallVectorBase::U"* %add.ptr.i.i.i.i2.i.i to i8*
+  store i8* %add.ptr.i.i.i.i.i.i, i8** %CapacityX.i.i.i.i.i.i, align 16, !tbaa !4
+  %EndX.i = getelementptr inbounds %"class.llvm::SmallVector"* %sv, i64 0, i32 0, i32 0, i32 0, i32 0, i32 1
+  %2 = load i8** %EndX.i, align 8, !tbaa !4
+  %CapacityX.i = getelementptr inbounds %"class.llvm::SmallVector"* %sv, i64 0, i32 0, i32 0, i32 0, i32 0, i32 2
+  %cmp.i = icmp ult i8* %2, %add.ptr.i.i.i.i.i.i
+  br i1 %cmp.i, label %Retry.i, label %if.end.i
+
+Retry.i:                                          ; preds = %.noexc, %entry
+  %3 = phi i8* [ %2, %entry ], [ %.pre.i, %.noexc ]
+  %new.isnull.i = icmp eq i8* %3, null
+  br i1 %new.isnull.i, label %invoke.cont, label %new.notnull.i
+
+new.notnull.i:                                    ; preds = %Retry.i
+  %4 = bitcast i8* %3 to i32*
+  store i32 1, i32* %4, align 4, !tbaa !5
+  br label %invoke.cont
+
+if.end.i:                                         ; preds = %entry
+  %5 = getelementptr inbounds %"class.llvm::SmallVector"* %sv, i64 0, i32 0, i32 0, i32 0, i32 0
+  invoke void @_ZN4llvm15SmallVectorBase8grow_podEmm(%"class.llvm::SmallVectorBase"* %5, i64 0, i64 4)
+          to label %.noexc unwind label %lpad
+
+.noexc:                                           ; preds = %if.end.i
+  %.pre.i = load i8** %EndX.i, align 8, !tbaa !4
+  br label %Retry.i
+
+invoke.cont:                                      ; preds = %new.notnull.i, %Retry.i
+  %add.ptr.i = getelementptr inbounds i8* %3, i64 4
+  store i8* %add.ptr.i, i8** %EndX.i, align 8, !tbaa !4
+  %6 = load i8** %CapacityX.i, align 16, !tbaa !4
+  %cmp.i8 = icmp ult i8* %add.ptr.i, %6
+  br i1 %cmp.i8, label %new.notnull.i11, label %if.end.i14
+
+Retry.i10:                                        ; preds = %if.end.i14
+  %.pre.i13 = load i8** %EndX.i, align 8, !tbaa !4
+  %new.isnull.i9 = icmp eq i8* %.pre.i13, null
+  br i1 %new.isnull.i9, label %invoke.cont2, label %new.notnull.i11
+
+new.notnull.i11:                                  ; preds = %invoke.cont, %Retry.i10
+  %7 = phi i8* [ %.pre.i13, %Retry.i10 ], [ %add.ptr.i, %invoke.cont ]
+  %8 = bitcast i8* %7 to i32*
+  store i32 2, i32* %8, align 4, !tbaa !5
+  br label %invoke.cont2
+
+if.end.i14:                                       ; preds = %invoke.cont
+  %9 = getelementptr inbounds %"class.llvm::SmallVector"* %sv, i64 0, i32 0, i32 0, i32 0, i32 0
+  invoke void @_ZN4llvm15SmallVectorBase8grow_podEmm(%"class.llvm::SmallVectorBase"* %9, i64 0, i64 4)
+          to label %Retry.i10 unwind label %lpad
+
+invoke.cont2:                                     ; preds = %new.notnull.i11, %Retry.i10
+  %10 = phi i8* [ null, %Retry.i10 ], [ %7, %new.notnull.i11 ]
+  %add.ptr.i12 = getelementptr inbounds i8* %10, i64 4
+  store i8* %add.ptr.i12, i8** %EndX.i, align 8, !tbaa !4
+  invoke void @_Z1gRN4llvm11SmallVectorIiLj8EEE(%"class.llvm::SmallVector"* %sv)
+          to label %invoke.cont3 unwind label %lpad
+
+invoke.cont3:                                     ; preds = %invoke.cont2
+  %11 = load i8** %BeginX.i.i.i.i.i.i, align 16, !tbaa !4
+  %cmp.i.i.i.i19 = icmp eq i8* %11, %1
+  br i1 %cmp.i.i.i.i19, label %_ZN4llvm11SmallVectorIiLj8EED1Ev.exit21, label %if.then.i.i.i20
+
+if.then.i.i.i20:                                  ; preds = %invoke.cont3
+  call void @free(i8* %11) #1
+  br label %_ZN4llvm11SmallVectorIiLj8EED1Ev.exit21
+
+_ZN4llvm11SmallVectorIiLj8EED1Ev.exit21:          ; preds = %invoke.cont3, %if.then.i.i.i20
+  call void @llvm.lifetime.end(i64 64, i8* %0) #1
+  ret void
+
+lpad:                                             ; preds = %if.end.i14, %if.end.i, %invoke.cont2
+  %12 = landingpad { i8*, i32 } personality i8* bitcast (i32 (...)* @__gxx_personality_v0 to i8*)
+          cleanup
+  %13 = load i8** %BeginX.i.i.i.i.i.i, align 16, !tbaa !4
+  %cmp.i.i.i.i = icmp eq i8* %13, %1
+  br i1 %cmp.i.i.i.i, label %eh.resume, label %if.then.i.i.i
+
+if.then.i.i.i:                                    ; preds = %lpad
+  call void @free(i8* %13) #1
+  br label %eh.resume
+
+eh.resume:                                        ; preds = %if.then.i.i.i, %lpad
+  resume { i8*, i32 } %12
+}
+
+; Function Attrs: nounwind
+declare void @llvm.lifetime.start(i64, i8* nocapture) #1
+
+declare i32 @__gxx_personality_v0(...)
+
+declare void @_Z1gRN4llvm11SmallVectorIiLj8EEE(%"class.llvm::SmallVector"*) #2
+
+; Function Attrs: nounwind
+declare void @llvm.lifetime.end(i64, i8* nocapture) #1
+
+declare void @_ZN4llvm15SmallVectorBase8grow_podEmm(%"class.llvm::SmallVectorBase"*, i64, i64) #2
+
+; Function Attrs: nounwind
+declare void @free(i8* nocapture) #3
+
+attributes #0 = { ssp uwtable "less-precise-fpmad"="false" "no-frame-pointer-elim"="true" "no-frame-pointer-elim-non-leaf" "no-infs-fp-math"="false" "no-nans-fp-math"="false" "stack-protector-buffer-size"="8" "unsafe-fp-math"="false" "use-soft-float"="false" }
+attributes #1 = { nounwind }
+attributes #2 = { "less-precise-fpmad"="false" "no-frame-pointer-elim"="true" "no-frame-pointer-elim-non-leaf" "no-infs-fp-math"="false" "no-nans-fp-math"="false" "stack-protector-buffer-size"="8" "unsafe-fp-math"="false" "use-soft-float"="false" }
+attributes #3 = { nounwind "less-precise-fpmad"="false" "no-frame-pointer-elim"="true" "no-frame-pointer-elim-non-leaf" "no-infs-fp-math"="false" "no-nans-fp-math"="false" "stack-protector-buffer-size"="8" "unsafe-fp-math"="false" "use-soft-float"="false" }
+
+!0 = metadata !{metadata !"any pointer", metadata !1}
+!1 = metadata !{metadata !"omnipotent char", metadata !2}
+!2 = metadata !{metadata !"Simple C/C++ TBAA"}
+!3 = metadata !{metadata !"int", metadata !1}
+!4 = metadata !{metadata !0, metadata !0, i64 0}
+!5 = metadata !{metadata !3, metadata !3, i64 0}
diff --git a/test/Transforms/GVN/local-pre.ll b/test/Transforms/GVN/local-pre.ll
index 1d0dadfbe0..2c92699dca 100644
--- a/test/Transforms/GVN/local-pre.ll
+++ b/test/Transforms/GVN/local-pre.ll
@@ -1,9 +1,9 @@
 ; RUN: opt < %s -gvn -enable-pre -S | grep "b.pre"
 
-define i32 @main(i32 %p) {
+define i32 @main(i32 %p, i32 %q) {
 block1:
-  
-	br i1 true, label %block2, label %block3
+    %cmp = icmp eq i32 %p, %q 
+	br i1 %cmp, label %block2, label %block3
 
 block2:
  %a = add i32 %p, 1
diff --git a/test/Transforms/GVN/rle-nonlocal.ll b/test/Transforms/GVN/rle-nonlocal.ll
index 6b74e9a946..8229aaa142 100644
--- a/test/Transforms/GVN/rle-nonlocal.ll
+++ b/test/Transforms/GVN/rle-nonlocal.ll
@@ -1,8 +1,9 @@
 ; RUN: opt < %s -basicaa -gvn -S | FileCheck %s
 
-define i32 @main(i32** %p) {
+define i32 @main(i32** %p, i32 %x, i32 %y) {
 block1:
-	br i1 true, label %block2, label %block3
+    %cmp = icmp eq i32 %x, %y
+	br i1 %cmp , label %block2, label %block3
 
 block2:
  %a = load i32** %p
diff --git a/test/Transforms/GVN/rle-semidominated.ll b/test/Transforms/GVN/rle-semidominated.ll
index 71aa548ab1..923cd03ecd 100644
--- a/test/Transforms/GVN/rle-semidominated.ll
+++ b/test/Transforms/GVN/rle-semidominated.ll
@@ -1,9 +1,10 @@
 ; RUN: opt < %s -basicaa -gvn -S | grep "DEAD = phi i32 "
 
-define i32 @main(i32* %p) {
+define i32 @main(i32* %p, i32 %x, i32 %y) {
 block1:
   %z = load i32* %p
-	br i1 true, label %block2, label %block3
+  %cmp = icmp eq i32 %x, %y
+	br i1 %cmp, label %block2, label %block3
 
 block2:
  br label %block4
diff --git a/test/Transforms/GVN/rle.ll b/test/Transforms/GVN/rle.ll
index 4c5d40a3c1..8d289b0699 100644
--- a/test/Transforms/GVN/rle.ll
+++ b/test/Transforms/GVN/rle.ll
@@ -369,13 +369,14 @@ Cont:
 ; CHECK: ret i8 %A
 }
 
-define i32 @chained_load(i32** %p) {
+define i32 @chained_load(i32** %p, i32 %x, i32 %y) {
 block1:
   %A = alloca i32*
 
   %z = load i32** %p
   store i32* %z, i32** %A
-  br i1 true, label %block2, label %block3
+  %cmp = icmp eq i32 %x, %y
+  br i1 %cmp, label %block2, label %block3
 
 block2:
  %a = load i32** %p
@@ -439,10 +440,11 @@ TY:
   ret i32 0
 }
 
-define i32 @phi_trans3(i32* %p) {
+define i32 @phi_trans3(i32* %p, i32 %x, i32 %y, i32 %z) {
 ; CHECK-LABEL: @phi_trans3(
 block1:
-  br i1 true, label %block2, label %block3
+  %cmpxy = icmp eq i32 %x, %y
+  br i1 %cmpxy, label %block2, label %block3
 
 block2:
  store i32 87, i32* %p
@@ -455,7 +457,7 @@ block3:
 
 block4:
   %A = phi i32 [-1, %block2], [42, %block3]
-  br i1 true, label %block5, label %exit
+  br i1 %cmpxy, label %block5, label %exit
   
 ; CHECK: block4:
 ; CHECK-NEXT: %D = phi i32 [ 87, %block2 ], [ 97, %block3 ]  
@@ -463,11 +465,11 @@ block4:
 
 block5:
   %B = add i32 %A, 1
-  br i1 true, label %block6, label %exit
+  br i1 %cmpxy, label %block6, label %exit
   
 block6:
   %C = getelementptr i32* %p, i32 %B
-  br i1 true, label %block7, label %exit
+  br i1 %cmpxy, label %block7, label %exit
   
 block7:
   %D = load i32* %C