diff --git a/llvm/test/Transforms/SimplifyCFG/hoist-common-code-with-unreachable.ll b/llvm/test/Transforms/SimplifyCFG/hoist-common-code-with-unreachable.ll
new file mode 100644
--- /dev/null
+++ b/llvm/test/Transforms/SimplifyCFG/hoist-common-code-with-unreachable.ll
@@ -0,0 +1,99 @@
+; NOTE: Assertions have been autogenerated by utils/update_test_checks.py
+; RUN: opt < %s -passes='simplifycfg<hoist-common-insts;no-sink-common-insts>' -simplifycfg-require-and-preserve-domtree=1 -S | FileCheck %s
+
+define i1 @common_instr_with_unreachable(i64 %a, i64 %b, i64 %c) {
+; CHECK-LABEL: @common_instr_with_unreachable(
+; CHECK-NEXT:  start:
+; CHECK-NEXT:    switch i64 [[A:%.*]], label [[UNREACHABLE:%.*]] [
+; CHECK-NEXT:    i64 0, label [[BB0:%.*]]
+; CHECK-NEXT:    i64 1, label [[BB1:%.*]]
+; CHECK-NEXT:    i64 2, label [[BB2:%.*]]
+; CHECK-NEXT:    ]
+; CHECK:       unreachable:
+; CHECK-NEXT:    unreachable
+; CHECK:       bb0:
+; CHECK-NEXT:    [[TMP0:%.*]] = icmp eq i64 [[B:%.*]], [[C:%.*]]
+; CHECK-NEXT:    br label [[EXIT:%.*]]
+; CHECK:       bb1:
+; CHECK-NEXT:    [[TMP1:%.*]] = icmp eq i64 [[B]], [[C]]
+; CHECK-NEXT:    br label [[EXIT]]
+; CHECK:       bb2:
+; CHECK-NEXT:    [[TMP2:%.*]] = icmp eq i64 [[B]], [[C]]
+; CHECK-NEXT:    br label [[EXIT]]
+; CHECK:       exit:
+; CHECK-NEXT:    [[RESULT:%.*]] = phi i1 [ [[TMP0]], [[BB0]] ], [ [[TMP1]], [[BB1]] ], [ [[TMP2]], [[BB2]] ]
+; CHECK-NEXT:    ret i1 [[RESULT]]
+;
+start:
+  switch i64 %a, label %unreachable [
+  i64 0, label %bb0
+  i64 1, label %bb1
+  i64 2, label %bb2
+  ]
+
+unreachable:
+  unreachable
+
+bb0:                                              ; preds = %start
+  %0 = icmp eq i64 %b, %c
+  br label %exit
+
+bb1:                                              ; preds = %start
+  %1 = icmp eq i64 %b, %c
+  br label %exit
+
+bb2:                                              ; preds = %start
+  %2 = icmp eq i64 %b, %c
+  br label %exit
+
+exit:                                             ; preds = %bb2, %bb1, %bb0
+  %result = phi i1 [ %0, %bb0 ], [ %1, %bb1 ], [ %2, %bb2 ]
+  ret i1 %result
+}
+
+define i1 @common_instr_with_unreachable_2(i64 %a, i64 %b, i64 %c) {
+; CHECK-LABEL: @common_instr_with_unreachable_2(
+; CHECK-NEXT:  start:
+; CHECK-NEXT:    switch i64 [[A:%.*]], label [[BB1:%.*]] [
+; CHECK-NEXT:    i64 0, label [[BB0:%.*]]
+; CHECK-NEXT:    i64 2, label [[BB2:%.*]]
+; CHECK-NEXT:    ]
+; CHECK:       bb0:
+; CHECK-NEXT:    [[TMP0:%.*]] = icmp eq i64 [[B:%.*]], [[C:%.*]]
+; CHECK-NEXT:    br label [[EXIT:%.*]]
+; CHECK:       bb1:
+; CHECK-NEXT:    [[TMP1:%.*]] = icmp eq i64 [[B]], [[C]]
+; CHECK-NEXT:    br label [[EXIT]]
+; CHECK:       bb2:
+; CHECK-NEXT:    [[TMP2:%.*]] = icmp eq i64 [[B]], [[C]]
+; CHECK-NEXT:    br label [[EXIT]]
+; CHECK:       exit:
+; CHECK-NEXT:    [[RESULT:%.*]] = phi i1 [ [[TMP0]], [[BB0]] ], [ [[TMP1]], [[BB1]] ], [ [[TMP2]], [[BB2]] ]
+; CHECK-NEXT:    ret i1 [[RESULT]]
+;
+start:
+  switch i64 %a, label %bb1 [
+  i64 0, label %bb0
+  i64 1, label %unreachable
+  i64 2, label %bb2
+  ]
+
+unreachable:
+  unreachable
+
+bb0:                                              ; preds = %start
+  %0 = icmp eq i64 %b, %c
+  br label %exit
+
+bb1:                                              ; preds = %start
+  %1 = icmp eq i64 %b, %c
+  br label %exit
+
+bb2:                                              ; preds = %start
+  %2 = icmp eq i64 %b, %c
+  br label %exit
+
+exit:                                             ; preds = %bb2, %bb1, %bb0
+  %result = phi i1 [ %0, %bb0 ], [ %1, %bb1 ], [ %2, %bb2 ]
+  ret i1 %result
+}
diff --git a/llvm/test/Transforms/SimplifyCFG/hoist-common-code.ll b/llvm/test/Transforms/SimplifyCFG/hoist-common-code.ll
--- a/llvm/test/Transforms/SimplifyCFG/hoist-common-code.ll
+++ b/llvm/test/Transforms/SimplifyCFG/hoist-common-code.ll
@@ -24,3 +24,88 @@
   ret void
 }
 
+define i1 @common_instr_on_switch(i64 %a, i64 %b, i64 %c) unnamed_addr {
+; CHECK-LABEL: @common_instr_on_switch(
+; CHECK-NEXT:  start:
+; CHECK-NEXT:    switch i64 [[A:%.*]], label [[BB0:%.*]] [
+; CHECK-NEXT:    i64 1, label [[BB1:%.*]]
+; CHECK-NEXT:    i64 2, label [[BB2:%.*]]
+; CHECK-NEXT:    ]
+; CHECK:       bb0:
+; CHECK-NEXT:    [[TMP0:%.*]] = icmp eq i64 [[B:%.*]], [[C:%.*]]
+; CHECK-NEXT:    br label [[EXIT:%.*]]
+; CHECK:       bb1:
+; CHECK-NEXT:    [[TMP1:%.*]] = icmp eq i64 [[B]], [[C]]
+; CHECK-NEXT:    br label [[EXIT]]
+; CHECK:       bb2:
+; CHECK-NEXT:    [[TMP2:%.*]] = icmp eq i64 [[B]], [[C]]
+; CHECK-NEXT:    br label [[EXIT]]
+; CHECK:       exit:
+; CHECK-NEXT:    [[RESULT:%.*]] = phi i1 [ [[TMP0]], [[BB0]] ], [ [[TMP1]], [[BB1]] ], [ [[TMP2]], [[BB2]] ]
+; CHECK-NEXT:    ret i1 [[RESULT]]
+;
+start:
+  switch i64 %a, label %bb0 [
+  i64 1, label %bb1
+  i64 2, label %bb2
+  ]
+
+bb0:                                              ; preds = %start
+  %0 = icmp eq i64 %b, %c
+  br label %exit
+
+bb1:                                              ; preds = %start
+  %1 = icmp eq i64 %b, %c
+  br label %exit
+
+bb2:                                              ; preds = %start
+  %2 = icmp eq i64 %b, %c
+  br label %exit
+
+exit:                                             ; preds = %bb2, %bb1, %bb0
+  %result = phi i1 [ %0, %bb0 ], [ %1, %bb1 ], [ %2, %bb2 ]
+  ret i1 %result
+}
+
+define i1 @partial_common_instr_on_switch(i64 %a, i64 %b, i64 %c) unnamed_addr {
+; CHECK-LABEL: @partial_common_instr_on_switch(
+; CHECK-NEXT:  start:
+; CHECK-NEXT:    switch i64 [[A:%.*]], label [[BB0:%.*]] [
+; CHECK-NEXT:    i64 1, label [[BB1:%.*]]
+; CHECK-NEXT:    i64 2, label [[BB2:%.*]]
+; CHECK-NEXT:    ]
+; CHECK:       bb0:
+; CHECK-NEXT:    [[TMP0:%.*]] = icmp eq i64 [[B:%.*]], [[C:%.*]]
+; CHECK-NEXT:    br label [[EXIT:%.*]]
+; CHECK:       bb1:
+; CHECK-NEXT:    [[TMP1:%.*]] = icmp ne i64 [[B]], [[C]]
+; CHECK-NEXT:    br label [[EXIT]]
+; CHECK:       bb2:
+; CHECK-NEXT:    [[TMP2:%.*]] = icmp eq i64 [[B]], [[C]]
+; CHECK-NEXT:    br label [[EXIT]]
+; CHECK:       exit:
+; CHECK-NEXT:    [[RESULT:%.*]] = phi i1 [ [[TMP0]], [[BB0]] ], [ [[TMP1]], [[BB1]] ], [ [[TMP2]], [[BB2]] ]
+; CHECK-NEXT:    ret i1 [[RESULT]]
+;
+start:
+  switch i64 %a, label %bb0 [
+  i64 1, label %bb1
+  i64 2, label %bb2
+  ]
+
+bb0:                                              ; preds = %start
+  %0 = icmp eq i64 %b, %c
+  br label %exit
+
+bb1:                                              ; preds = %start
+  %1 = icmp ne i64 %b, %c
+  br label %exit
+
+bb2:                                              ; preds = %start
+  %2 = icmp eq i64 %b, %c
+  br label %exit
+
+exit:                                             ; preds = %bb2, %bb1, %bb0
+  %result = phi i1 [ %0, %bb0 ], [ %1, %bb1 ], [ %2, %bb2 ]
+  ret i1 %result
+}