diff --git a/llvm/lib/Transforms/Scalar/SimpleLoopUnswitch.cpp b/llvm/lib/Transforms/Scalar/SimpleLoopUnswitch.cpp
--- a/llvm/lib/Transforms/Scalar/SimpleLoopUnswitch.cpp
+++ b/llvm/lib/Transforms/Scalar/SimpleLoopUnswitch.cpp
@@ -796,6 +796,13 @@
     if (!ExitL || ExitL->contains(OuterL))
       OuterL = ExitL;
   }
+  for (unsigned Index : ExitCaseIndices) {
+    auto CaseI = SI.case_begin() + Index;
+    // Compute the outer loop from this exit.
+    Loop *ExitL = LI.getLoopFor(CaseI->getCaseSuccessor());
+    if (!ExitL || ExitL->contains(OuterL))
+      OuterL = ExitL;
+  }
 
   if (SE) {
     if (OuterL)
@@ -821,10 +828,6 @@
   // and don't disrupt the earlier indices.
   for (unsigned Index : reverse(ExitCaseIndices)) {
     auto CaseI = SI.case_begin() + Index;
-    // Compute the outer loop from this exit.
-    Loop *ExitL = LI.getLoopFor(CaseI->getCaseSuccessor());
-    if (!ExitL || ExitL->contains(OuterL))
-      OuterL = ExitL;
     // Save the value of this case.
     auto W = SIW.getSuccessorWeight(CaseI->getSuccessorIndex());
     ExitCases.emplace_back(CaseI->getCaseValue(), CaseI->getCaseSuccessor(), W);
diff --git a/llvm/test/Transforms/SimpleLoopUnswitch/update-scev-2.ll b/llvm/test/Transforms/SimpleLoopUnswitch/update-scev-2.ll
new file mode 100644
--- /dev/null
+++ b/llvm/test/Transforms/SimpleLoopUnswitch/update-scev-2.ll
@@ -0,0 +1,87 @@
+; NOTE: Assertions have been autogenerated by utils/update_test_checks.py UTC_ARGS: --version 2
+; RUN: opt < %s -passes='print<scalar-evolution>,simple-loop-unswitch<no-nontrivial>,print<scalar-evolution>' -disable-output 2>&1 | FileCheck -check-prefix CHECK-SCEV %s
+; RUN: opt < %s -passes='function(loop-deletion,simple-loop-unswitch<no-nontrivial>),verify<scalar-evolution>' -S | FileCheck -check-prefix CHECK-IR %s
+
+; These tests used to crash in debug builds:
+;
+;   opt: ../lib/Analysis/ScalarEvolution.cpp:8569: const llvm::SCEV* llvm::ScalarEvolution::BackedgeTakenInfo::getExact(const llvm::Loop*, llvm::ScalarEvolution*, llvm::SmallVector<const llvm::SCEVPredicate*, 4>*) const: Assertion `SE->DT.dominates(ENT.ExitingBlock, Latch) && "We should only have known counts for exiting blocks that dominate " "latch!"' failed.
+;   Stack dump:
+;   0.  Program arguments: /bin/opt -passes=function(loop-deletion,simple-loop-unswitch<no-nontrivial>),verify<scalar-evolution> -o - test.ll -S
+;    #0 0x00000000035912c8 llvm::sys::PrintStackTrace(llvm::raw_ostream&, int) (/bin/opt+0x35912c8)
+;    #1 0x000000000358ebcc SignalHandler(int) Signals.cpp:0:0
+;    #2 0x00007f546e44d630 __restore_rt sigaction.c:0:0
+;    #3 0x00007f546bdaa387 raise (/lib64/libc.so.6+0x36387)
+;    #4 0x00007f546bdaba78 abort (/lib64/libc.so.6+0x37a78)
+;    #5 0x00007f546bda31a6 __assert_fail_base (/lib64/libc.so.6+0x2f1a6)
+;    #6 0x00007f546bda3252 (/lib64/libc.so.6+0x2f252)
+;    #7 0x000000000256b842 llvm::ScalarEvolution::BackedgeTakenInfo::getExact(...) const (.part.0) ScalarEvolution.cpp:0:0
+;    #8 0x0000000002594d6e llvm::ScalarEvolution::verify() const (/bin/opt+0x2594d6e)
+;
+; Verify that we no longer hit that assert, while we expect to have forgotten SCEV for the outer loop.
+; Also added checks to show and verify the IR transformation.
+
+
+; Before the unswitch:
+;
+; CHECK-SCEV: Classifying expressions for: @f4
+; CHECK-SCEV-NEXT:   %j.0 = phi i16 [ 0, %entry ], [ %0, %sw.bb2 ]
+; CHECK-SCEV-NEXT:   -->  {0,+,1}<nuw><nsw><%lbl1> U: [0,3) S: [0,3)               Exits: 2                LoopDispositions: { %lbl1: Computable, %lbl2: Invariant }
+; CHECK-SCEV-NEXT:   %0 = add i16 %j.0, 1
+; CHECK-SCEV-NEXT:   -->  {1,+,1}<nuw><nsw><%lbl1> U: [1,4) S: [1,4)               Exits: 3                LoopDispositions: { %lbl1: Computable, %lbl2: Invariant }
+; CHECK-SCEV-DAG: Loop %lbl2: Unpredictable backedge-taken count.
+; CHECK-SCEV-DAG: Loop %lbl1: backedge-taken count is 2
+;
+; After the unswitch:
+;
+; CHECK-SCEV: Classifying expressions for: @f4
+; CHECK-SCEV-NEXT:  %j.0 = phi i16 [ 0, %entry ], [ %0, %sw.bb2 ]
+; CHECK-SCEV-NEXT:  -->  {0,+,1}<nuw><nsw><%lbl1> U: [0,-32768) S: [0,-32768)             Exits: <<Unknown>>              LoopDispositions: { %lbl1: Computable }
+; CHECK-SCEV-NEXT:  %0 = add i16 %j.0, 1
+; CHECK-SCEV-NEXT:  -->  {1,+,1}<nuw><nsw><%lbl1> U: [1,-32768) S: [1,-32768)             Exits: <<Unknown>>              LoopDispositions: { %lbl1: Computable }
+; CHECK-SCEV-DAG: Loop %lbl1: Unpredictable backedge-taken count.
+; CHECK-SCEV-DAG: Loop %lbl2: <multiple exits> Unpredictable backedge-taken count.
+
+
+define i16 @f4() {
+; CHECK-IR-LABEL: define i16 @f4() {
+; CHECK-IR-NEXT:  entry:
+; CHECK-IR-NEXT:    br label [[LBL1:%.*]]
+; CHECK-IR:       lbl1:
+; CHECK-IR-NEXT:    [[J_0:%.*]] = phi i16 [ 0, [[ENTRY:%.*]] ], [ [[TMP0:%.*]], [[SW_BB2:%.*]] ]
+; CHECK-IR-NEXT:    switch i16 [[J_0]], label [[LBL1_SPLIT:%.*]] [
+; CHECK-IR-NEXT:    i16 0, label [[SW_BB2]]
+; CHECK-IR-NEXT:    i16 1, label [[SW_BB2]]
+; CHECK-IR-NEXT:    i16 2, label [[LBL3:%.*]]
+; CHECK-IR-NEXT:    ]
+; CHECK-IR:       lbl1.split:
+; CHECK-IR-NEXT:    br label [[LBL2:%.*]]
+; CHECK-IR:       lbl2:
+; CHECK-IR-NEXT:    br label [[LBL2]]
+; CHECK-IR:       sw.bb2:
+; CHECK-IR-NEXT:    [[TMP0]] = add i16 [[J_0]], 1
+; CHECK-IR-NEXT:    br label [[LBL1]]
+; CHECK-IR:       lbl3:
+; CHECK-IR-NEXT:    ret i16 0
+;
+entry:
+  br label %lbl1
+
+lbl1:                                             ; preds = %sw.bb2, %entry
+  %j.0 = phi i16 [ 0, %entry ], [ %0, %sw.bb2 ]
+  br label %lbl2
+
+lbl2:                                             ; preds = %lbl2, %lbl1
+  switch i16 %j.0, label %lbl2 [
+  i16 0, label %sw.bb2
+  i16 1, label %sw.bb2
+  i16 2, label %lbl3
+  ]
+
+sw.bb2:                                           ; preds = %lbl2, %lbl2
+  %0 = add i16 %j.0, 1
+  br label %lbl1
+
+lbl3:                                             ; preds = %lbl2
+  ret i16 0
+}
+