diff --git a/lib/Transforms/Utils/LoopUnrollRuntime.cpp b/lib/Transforms/Utils/LoopUnrollRuntime.cpp
index 386ec89..00d2fd2 100644
--- a/lib/Transforms/Utils/LoopUnrollRuntime.cpp
+++ b/lib/Transforms/Utils/LoopUnrollRuntime.cpp
@@ -805,10 +805,7 @@
   // Now the loop blocks are cloned and the other exiting blocks from the
   // remainder are connected to the original Loop's exit blocks. The remaining
   // work is to update the phi nodes in the original loop, and take in the
-  // values from the cloned region. Also update the dominator info for
-  // OtherExits and their immediate successors, since we have new edges into
-  // OtherExits.
-  SmallPtrSet<BasicBlock*, 8> ImmediateSuccessorsOfExitBlocks;
+  // values from the cloned region.
   for (auto *BB : OtherExits) {
    for (auto &II : *BB) {
 
@@ -843,27 +840,30 @@
              "Breaks the definition of dedicated exits!");
     }
 #endif
-   // Update the dominator info because the immediate dominator is no longer the
-   // header of the original Loop. BB has edges both from L and remainder code.
-   // Since the preheader determines which loop is run (L or directly jump to
-   // the remainder code), we set the immediate dominator as the preheader.
-   if (DT) {
-     DT->changeImmediateDominator(BB, PreHeader);
-     // Also update the IDom for immediate successors of BB.  If the current
-     // IDom is the header, update the IDom to be the preheader because that is
-     // the nearest common dominator of all predecessors of SuccBB.  We need to
-     // check for IDom being the header because successors of exit blocks can
-     // have edges from outside the loop, and we should not incorrectly update
-     // the IDom in that case.
-     for (BasicBlock *SuccBB: successors(BB))
-       if (ImmediateSuccessorsOfExitBlocks.insert(SuccBB).second) {
-         if (DT->getNode(SuccBB)->getIDom()->getBlock() == Header) {
-           assert(!SuccBB->getSinglePredecessor() &&
-                  "BB should be the IDom then!");
-           DT->changeImmediateDominator(SuccBB, PreHeader);
-         }
-       }
+  }
+
+  // Update the immediate dominator of the exit blocks and blocks that are
+  // reachable from the exit blocks. This is needed because we now have paths
+  // from both the original loop and the remainder code reaching the exit
+  // blocks. While the IDom of these exit blocks were from the original loop,
+  // now the IDom is the preheader (which decides whether the original loop or
+  // remainder code should run).
+  if (DT && !L->getExitingBlock()) {
+    SmallVector<BasicBlock *, 16> ChildrenToUpdate;
+    // NB! We have to examine the dom children of all loop blocks, not just
+    // those which are the IDom of the exit blocks. This is because blocks
+    // reachable from the exit blocks can have their IDom as the nearest common
+    // dominator of the exit blocks.
+    for (auto *BB : L->blocks()) {
+      auto *DomNodeBB = DT->getNode(BB);
+      for (auto *DomChild : DomNodeBB->getChildren()) {
+        auto *DomChildBB = DomChild->getBlock();
+        if (!L->contains(LI->getLoopFor(DomChildBB)))
+          ChildrenToUpdate.push_back(DomChildBB);
+      }
     }
+    for (auto *BB : ChildrenToUpdate)
+      DT->changeImmediateDominator(BB, PreHeader);
   }
 
   // Loop structure should be the following:
diff --git a/test/Transforms/LoopUnroll/runtime-loop-multiexit-dom-verify.ll b/test/Transforms/LoopUnroll/runtime-loop-multiexit-dom-verify.ll
index 6014775..b3c0039 100644
--- a/test/Transforms/LoopUnroll/runtime-loop-multiexit-dom-verify.ll
+++ b/test/Transforms/LoopUnroll/runtime-loop-multiexit-dom-verify.ll
@@ -124,3 +124,152 @@
 exitsucc:                                              ; preds = %headerexit
   ret i64 96
 }
+
+; exit block (%default) has an exiting block and another exit block as predecessors.
+define void @test4(i16 %c3) {
+; CHECK-LABEL: test4
+
+; CHECK-LABEL: exiting.prol:
+; CHECK-NEXT:   switch i16 %c3, label %default.loopexit.loopexit1 [
+
+; CHECK-LABEL: exiting:
+; CHECK-NEXT:   switch i16 %c3, label %default.loopexit.loopexit [
+
+; CHECK-LABEL: default.loopexit.loopexit:
+; CHECK-NEXT:   br label %default.loopexit
+
+; CHECK-LABEL: default.loopexit.loopexit1:
+; CHECK-NEXT:   br label %default.loopexit
+
+; CHECK-LABEL: default.loopexit:
+; CHECK-NEXT:   br label %default
+preheader:
+  %c1 = zext i32 undef to i64
+  br label %header
+
+header:                                       ; preds = %latch, %preheader
+  %indvars.iv = phi i64 [ 0, %preheader ], [ %indvars.iv.next, %latch ]
+  br label %exiting
+
+exiting:                                           ; preds = %header
+  switch i16 %c3, label %default [
+    i16 45, label %otherexit
+    i16 95, label %latch
+  ]
+
+latch:                                          ; preds = %exiting
+  %indvars.iv.next = add nuw nsw i64 %indvars.iv, 1
+  %c2 = icmp ult i64 %indvars.iv.next, %c1
+  br i1 %c2, label %header, label %latchexit
+
+latchexit:                                          ; preds = %latch
+  ret void
+
+default:                                          ; preds = %otherexit, %exiting
+  ret void
+
+otherexit:                                           ; preds = %exiting
+  br label %default
+}
+
+; exit block (%exitB) has an exiting block and another exit block as predecessors.
+; exiting block comes from inner loop.
+define void @test5() {
+; CHECK-LABEL: test5
+; CHECK-LABEL: bb1:
+; CHECK-NEXT:   br i1 false, label %outerH.prol.preheader, label %outerH.prol.loopexit
+
+; CHECK-LABEL: outerH.prol.preheader:
+; CHECK-NEXT:   br label %outerH.prol
+
+; CHECK-LABEL: outerH.prol:
+; CHECK-NEXT:   %tmp4.prol = phi i32 [ %tmp6.prol, %outerLatch.prol ], [ undef, %outerH.prol.preheader ]
+; CHECK-NEXT:   %prol.iter = phi i32 [ 0, %outerH.prol.preheader ], [ %prol.iter.sub, %outerLatch.prol ]
+; CHECK-NEXT:   br label %innerH.prol
+bb:
+  %tmp = icmp sgt i32 undef, 79
+  br i1 %tmp, label %outerLatchExit, label %bb1
+
+bb1:                                              ; preds = %bb
+  br label %outerH
+
+outerH:                                              ; preds = %outerLatch, %bb1
+  %tmp4 = phi i32 [ %tmp6, %outerLatch ], [ undef, %bb1 ]
+  br label %innerH
+
+innerH:                                              ; preds = %innerLatch, %outerH
+  br i1 undef, label %innerexiting, label %otherexitB
+
+innerexiting:                                             ; preds = %innerH
+  br i1 undef, label %innerLatch, label %exitB
+
+innerLatch:                                             ; preds = %innerexiting
+  %tmp13 = fcmp olt double undef, 2.000000e+00
+  br i1 %tmp13, label %innerH, label %outerLatch
+
+outerLatch:                                              ; preds = %innerLatch
+  %tmp6 = add i32 %tmp4, 1
+  %tmp7 = icmp sgt i32 %tmp6, 79
+  br i1 %tmp7, label %outerLatchExit, label %outerH
+
+outerLatchExit:                                              ; preds = %outerLatch, %bb
+  ret void
+
+exitB:                                             ; preds = %innerexiting, %otherexitB
+  ret void
+
+otherexitB:                                              ; preds = %innerH
+  br label %exitB
+
+}
+
+; Blocks reachable from exits (not_zero44) have the IDom as the block within the loop (Header).
+; Update the IDom to the preheader.
+define void @test6() {
+; CHECK-LABEL: test6
+; CHECK-LABEL: header.prol.preheader:
+; CHECK-NEXT:    br label %header.prol
+
+; CHECK-LABEL: header.prol:
+; CHECK-NEXT:    %indvars.iv.prol = phi i64 [ undef, %header.prol.preheader ], [ %indvars.iv.next.prol, %latch.prol ]
+; CHECK-NEXT:    %prol.iter = phi i64 [ 1, %header.prol.preheader ], [ %prol.iter.sub, %latch.prol ]
+; CHECK-NEXT:    br i1 false, label %latch.prol, label %otherexit.loopexit1
+
+; CHECK-LABEL: header.prol.loopexit.unr-lcssa:
+; CHECK-NEXT:    %indvars.iv.unr.ph = phi i64 [ %indvars.iv.next.prol, %latch.prol ]
+; CHECK-NEXT:    br label %header.prol.loopexit
+
+; CHECK-LABEL: header.prol.loopexit:
+; CHECK-NEXT:    %indvars.iv.unr = phi i64 [ undef, %entry ], [ %indvars.iv.unr.ph, %header.prol.loopexit.unr-lcssa ]
+; CHECK-NEXT:    br i1 true, label %latchexit, label %entry.new
+
+; CHECK-LABEL: entry.new:
+; CHECK-NEXT:    br label %header
+entry:
+  br label %header
+
+header:                                          ; preds = %latch, %entry
+  %indvars.iv = phi i64 [ undef, %entry ], [ %indvars.iv.next, %latch ]
+  br i1 undef, label %latch, label %otherexit
+
+latch:                                         ; preds = %header
+  %indvars.iv.next = add nsw i64 %indvars.iv, 2
+  %0 = icmp slt i64 %indvars.iv.next, 616
+  br i1 %0, label %header, label %latchexit
+
+latchexit:                                          ; preds = %latch
+  br label %latchexitsucc
+
+otherexit:                                 ; preds = %header
+  br label %otherexitsucc
+
+otherexitsucc:                                          ; preds = %otherexit
+  br label %not_zero44
+
+not_zero44:                                       ; preds = %latchexitsucc, %otherexitsucc
+  unreachable
+
+latchexitsucc:                                      ; preds = %latchexit
+  br label %not_zero44
+}
+