Index: llvm/lib/Transforms/Scalar/JumpThreading.cpp
===================================================================
--- llvm/lib/Transforms/Scalar/JumpThreading.cpp
+++ llvm/lib/Transforms/Scalar/JumpThreading.cpp
@@ -617,6 +617,7 @@
     // "X < 4" and "X < 3" is known true but "X < 4" itself is not available.
     // Perhaps getConstantOnEdge should be smart enough to do this?
 
+    DDT->flush(); // LVI analysis relies on an up-to-date DominatorTree.
     for (BasicBlock *P : predecessors(BB)) {
       // If the value is known by LazyValueInfo to be a constant in a
       // predecessor, use that information to try to thread this block.
@@ -630,6 +631,7 @@
 
   /// If I is a PHI node, then we know the incoming values for any constants.
   if (PHINode *PN = dyn_cast<PHINode>(I)) {
+    DDT->flush(); // LVI analysis relies on an up-to-date DominatorTree.
     for (unsigned i = 0, e = PN->getNumIncomingValues(); i != e; ++i) {
       Value *InVal = PN->getIncomingValue(i);
       if (Constant *KC = getKnownConstant(InVal, Preference)) {
@@ -769,6 +771,7 @@
           if (!isa<Constant>(RHS))
             continue;
 
+          DDT->flush(); // LVI analysis relies on an up-to-date DominatorTree.
           LazyValueInfo::Tristate
             ResT = LVI->getPredicateOnEdge(Pred, LHS,
                                            cast<Constant>(RHS), PredBB, BB,
@@ -792,6 +795,7 @@
 
       if (!isa<Instruction>(CmpLHS) ||
           cast<Instruction>(CmpLHS)->getParent() != BB) {
+        DDT->flush(); // LVI analysis relies on an up-to-date DominatorTree.
         for (BasicBlock *P : predecessors(BB)) {
           // If the value is known by LazyValueInfo to be a constant in a
           // predecessor, use that information to try to thread this block.
@@ -820,6 +824,7 @@
             match(CmpLHS, m_Add(m_Value(AddLHS), m_ConstantInt(AddConst)))) {
           if (!isa<Instruction>(AddLHS) ||
               cast<Instruction>(AddLHS)->getParent() != BB) {
+            DDT->flush(); // LVI analysis relies on an up-to-date DominatorTree.
             for (BasicBlock *P : predecessors(BB)) {
               // If the value is known by LazyValueInfo to be a ConstantRange in
               // a predecessor, use that information to try to thread this
@@ -900,6 +905,7 @@
     }
   }
 
+  DDT->flush(); // LVI analysis relies on an up-to-date DominatorTree.
   // If all else fails, see if LVI can figure out a constant value for us.
   Constant *CI = LVI->getConstant(V, BB, CxtI);
   if (Constant *KC = getKnownConstant(CI, Preference)) {
@@ -1101,7 +1107,7 @@
       // unconditional. Because its no longer interesting as far as jump
       // threading is concerned.
       assert(CondBr->isConditional() && "Threading on unconditional terminator");
-
+      DDT->flush(); // LVI analysis relies on an up-to-date DominatorTree.
       LazyValueInfo::Tristate Ret =
         LVI->getPredicateAt(CondCmp->getPredicate(), CondCmp->getOperand(0),
                             CondConst, CondBr);
@@ -2371,6 +2377,7 @@
     // Now check if one of the select values would allow us to constant fold the
     // terminator in BB. We don't do the transform if both sides fold, those
     // cases will be threaded in any case.
+    DDT->flush(); // LVI analysis relies on an up-to-date DominatorTree.
     LazyValueInfo::Tristate LHSFolds =
         LVI->getPredicateOnEdge(CondCmp->getPredicate(), SI->getOperand(1),
                                 CondRHS, Pred, BB, CondCmp);
Index: llvm/test/Transforms/JumpThreading/pr36133.ll
===================================================================
--- /dev/null
+++ llvm/test/Transforms/JumpThreading/pr36133.ll
@@ -0,0 +1,44 @@
+; RUN: opt -jump-threading -S < %s | FileCheck %s
+@global = external global i8*, align 8
+
+define i32 @foo(i32 %arg) {
+; CHECK-LABEL: @foo
+; CHECK-LABEL: bb:
+; CHECK: icmp eq
+; CHECK-NEXT: br i1 %tmp1, label %bb7, label %bb7
+bb:
+  %tmp = load i8*, i8** @global, align 8
+  %tmp1 = icmp eq i8* %tmp, null
+  br i1 %tmp1, label %bb3, label %bb2
+
+; CHECK-NOT: bb2:
+bb2:
+  br label %bb3
+
+; CHECK-NOT: bb3:
+bb3:
+  %tmp4 = phi i8 [ 1, %bb2 ], [ 0, %bb ]
+  %tmp5 = icmp eq i8 %tmp4, 0
+  br i1 %tmp5, label %bb7, label %bb6
+
+; CHECK-NOT: bb6:
+bb6:
+  br label %bb7
+
+; CHECK-LABEL: bb7:
+bb7:
+  %tmp8 = icmp eq i32 %arg, -1
+  br i1 %tmp8, label %bb9, label %bb10
+
+; CHECK-LABEL: bb9:
+bb9:
+  ret i32 0
+
+; CHECK-LABEL: bb10:
+bb10:
+  %tmp11 = icmp sgt i32 %arg, -1
+  call void @llvm.assume(i1 %tmp11)
+  ret i32 1
+}
+
+declare void @llvm.assume(i1)