diff --git a/llvm/lib/Transforms/Scalar/GVNSink.cpp b/llvm/lib/Transforms/Scalar/GVNSink.cpp
--- a/llvm/lib/Transforms/Scalar/GVNSink.cpp
+++ b/llvm/lib/Transforms/Scalar/GVNSink.cpp
@@ -388,6 +388,7 @@
   BumpPtrAllocator Allocator;
   ArrayRecycler<Value *> Recycler;
   uint32_t nextValueNumber = 1;
+  const DominatorTree *DT = nullptr;
 
   /// Create an expression for I based on its opcode and its uses. If I
   /// touches or reads memory, the expression is also based upon its memory
@@ -418,6 +419,7 @@
 
 public:
   ValueTable() = default;
+  explicit ValueTable(const DominatorTree *DT) : DT(DT) {}
 
   /// Returns the value number for the specified value, assigning
   /// it a new number if it did not have one before.
@@ -432,6 +434,9 @@
     }
 
     Instruction *I = cast<Instruction>(V);
+    if (DT && !DT->isReachableFromEntry(I->getParent()))
+      return ~0U;
+
     InstructionUseExpr *exp = nullptr;
     switch (I->getOpcode()) {
     case Instruction::Load:
@@ -561,11 +566,11 @@
 class GVNSink {
 public:
   GVNSink() = default;
+  explicit GVNSink(const DominatorTree *DT) : VN(DT) {}
 
   bool run(Function &F) {
     LLVM_DEBUG(dbgs() << "GVNSink: running on function @" << F.getName()
                       << "\n");
-
     unsigned NumSunk = 0;
     ReversePostOrderTraversal<Function*> RPOT(&F);
     for (auto *N : RPOT)
@@ -895,7 +900,9 @@
   bool runOnFunction(Function &F) override {
     if (skipFunction(F))
       return false;
-    GVNSink G;
+    auto *DTWP = getAnalysisIfAvailable<DominatorTreeWrapperPass>();
+    auto *DT = DTWP ? &DTWP->getDomTree() : nullptr;
+    GVNSink G(DT);
     return G.run(F);
   }
 
@@ -907,7 +914,8 @@
 } // end anonymous namespace
 
 PreservedAnalyses GVNSinkPass::run(Function &F, FunctionAnalysisManager &AM) {
-  GVNSink G;
+  DominatorTree *DT = &AM.getResult<DominatorTreeAnalysis>(F);
+  GVNSink G(DT);
   if (!G.run(F))
     return PreservedAnalyses::all();
   return PreservedAnalyses::none();
diff --git a/llvm/test/Transforms/GVNSink/sink-common-code.ll b/llvm/test/Transforms/GVNSink/sink-common-code.ll
--- a/llvm/test/Transforms/GVNSink/sink-common-code.ll
+++ b/llvm/test/Transforms/GVNSink/sink-common-code.ll
@@ -759,6 +759,43 @@
   ret i32 1
 }
 
+@0 = global i32 0, align 4
+@1 = global i8 0, align 2
+
+; CHECK-LABEL: test_pr36954
+; CHECK-NOT: xor
+; PR36954 reproducer containing self referencing instruction shouldn't crash GVNSink pass.
+define void @test_pr36954() {
+bb1:
+  %i1 = load i32, i32* @0, align 4
+  %i2 = trunc i32 %i1 to i8
+  br label %bb2
+
+bb2:
+  %i3 = phi i32 [ 0, %bb1 ], [ %i10, %bb5 ]
+  %i4 = icmp eq i32 %i3, 0
+  br i1 %i4, label %bb5, label %exit
+
+bb3:
+  br i1 %i4, label %bb5, label %bb4
+
+bb4:
+  %i5 = load i8, i8* @1, align 2
+  %i6 = sub i8 %i2, %i5
+  store i8 %i6, i8* @1, align 2
+  %i7 = zext i8 %i6 to i32
+  %i8 = xor i32 %i8, %i7
+  %i9 = icmp eq i32 %i8, 0
+  br i1 %i9, label %exit, label %bb3
+
+bb5:
+  %i10 = phi i32 [ %i3, %bb2 ], [ %i8, %bb3 ]
+  br label %bb2
+
+exit:
+  ret void
+}
+
 ; CHECK: !0 = !{!1, !1, i64 0}
 ; CHECK: !1 = !{!"float", !2}
 ; CHECK: !2 = !{!"an example type tree"}