diff --git a/llvm/test/Transforms/SimplifyCFG/PR9946.ll b/llvm/test/Transforms/SimplifyCFG/PR9946.ll
@@ -1,4 +1,4 @@
-; RUN: opt -simplifycfg -disable-output < %s
+; RUN: opt -simplifycfg -simplifycfg-require-and-preserve-domtree=1 -disable-output < %s
 
 @foo = external constant i32
 

diff --git a/llvm/test/Transforms/SimplifyCFG/PhiBlockMerge.ll b/llvm/test/Transforms/SimplifyCFG/PhiBlockMerge.ll
@@ -1,7 +1,7 @@
 ; NOTE: Assertions have been autogenerated by update_test_checks.py
 ; Test merging of blocks that only have PHI nodes in them
 ;
-; RUN: opt < %s -simplifycfg -S | FileCheck %s
+; RUN: opt < %s -simplifycfg -simplifycfg-require-and-preserve-domtree=1 -S | FileCheck %s
 ;
 
 define i32 @test(i1 %a, i1 %b) {

diff --git a/llvm/test/Transforms/SimplifyCFG/PhiEliminate2.ll b/llvm/test/Transforms/SimplifyCFG/PhiEliminate2.ll
@@ -1,4 +1,4 @@
-; RUN: opt < %s -simplifycfg -S | FileCheck %s
+; RUN: opt < %s -simplifycfg -simplifycfg-require-and-preserve-domtree=1 -S | FileCheck %s
 
 ; Use a select to make this a single BB.
 ; Also, make sure the profile metadata is propagated to the select (PR26636).

diff --git a/llvm/test/Transforms/SimplifyCFG/RISCV/select-trunc-i64.ll b/llvm/test/Transforms/SimplifyCFG/RISCV/select-trunc-i64.ll
@@ -1,4 +1,4 @@
-;RUN: opt -S -simplifycfg -mtriple=riscv32 < %s | FileCheck %s
+;RUN: opt -S -simplifycfg -simplifycfg-require-and-preserve-domtree=1 -mtriple=riscv32 < %s | FileCheck %s
 
 ; Test case taken from test/Transforms/SimplifyCFG/ARM/select-trunc-i64.ll.
 ; A correct implementation of isTruncateFree allows this test case to be

diff --git a/llvm/test/Transforms/SimplifyCFG/UncondBranchToReturn.ll b/llvm/test/Transforms/SimplifyCFG/UncondBranchToReturn.ll
@@ -2,7 +2,7 @@
 ; a PHI node and a return.  Make sure the simplify cfg can straighten out this
 ; important case.  This is basically the most trivial form of tail-duplication.
 
-; RUN: opt < %s -simplifycfg -hoist-common-insts=true -S | \
+; RUN: opt < %s -simplifycfg -simplifycfg-require-and-preserve-domtree=1 -hoist-common-insts=true -S | \
 ; RUN:    not grep "br label"
 
 define i32 @test(i1 %B, i32 %A, i32 %B.upgrd.1) {

diff --git a/llvm/test/Transforms/SimplifyCFG/UnreachableEliminate.ll b/llvm/test/Transforms/SimplifyCFG/UnreachableEliminate.ll
@@ -1,5 +1,5 @@
 ; NOTE: Assertions have been autogenerated by utils/update_test_checks.py
-; RUN: opt < %s -simplifycfg -S | FileCheck %s
+; RUN: opt < %s -simplifycfg -simplifycfg-require-and-preserve-domtree=1 -S | FileCheck %s
 
 define void @test1(i1 %C, i1* %BP) {
 ; CHECK-LABEL: @test1(

diff --git a/llvm/test/Transforms/SimplifyCFG/X86/CoveredLookupTable.ll b/llvm/test/Transforms/SimplifyCFG/X86/CoveredLookupTable.ll
@@ -1,5 +1,5 @@
 ; NOTE: Assertions have been autogenerated by utils/update_test_checks.py
-; RUN: opt -simplifycfg -switch-to-lookup -S %s | FileCheck %s
+; RUN: opt -simplifycfg -simplifycfg-require-and-preserve-domtree=1 -switch-to-lookup -S %s | FileCheck %s
 ; RUN: opt -passes='simplify-cfg<switch-to-lookup>' -S %s | FileCheck %s
 ; rdar://15268442
 

diff --git a/llvm/test/Transforms/SimplifyCFG/X86/PR29163.ll b/llvm/test/Transforms/SimplifyCFG/X86/PR29163.ll
@@ -1,4 +1,4 @@
-; RUN: opt -S -simplifycfg < %s | FileCheck %s
+; RUN: opt -S -simplifycfg -simplifycfg-require-and-preserve-domtree=1 < %s | FileCheck %s
 target datalayout = "e-m:e-i64:64-f80:128-n8:16:32:64-S128"
 target triple = "x86_64-unknown-linux-gnu"
 

diff --git a/llvm/test/Transforms/SimplifyCFG/X86/PR30210.ll b/llvm/test/Transforms/SimplifyCFG/X86/PR30210.ll
@@ -1,5 +1,5 @@
 ; NOTE: Assertions have been autogenerated by utils/update_test_checks.py
-; RUN: opt -S -simplifycfg < %s | FileCheck %s
+; RUN: opt -S -simplifycfg -simplifycfg-require-and-preserve-domtree=1 < %s | FileCheck %s
 target datalayout = "e-m:e-i64:64-f80:128-n8:16:32:64-S128"
 target triple = "x86_64-unknown-linux-gnu"
 

diff --git a/llvm/test/Transforms/SimplifyCFG/X86/SpeculativeExec.ll b/llvm/test/Transforms/SimplifyCFG/X86/SpeculativeExec.ll
@@ -1,5 +1,5 @@
 ; NOTE: Assertions have been autogenerated by utils/update_test_checks.py
-; RUN: opt < %s -simplifycfg -phi-node-folding-threshold=2 -S | FileCheck %s
+; RUN: opt < %s -simplifycfg -simplifycfg-require-and-preserve-domtree=1 -phi-node-folding-threshold=2 -S | FileCheck %s
 
 target datalayout = "e-p:64:64:64-i1:8:8-i8:8:8-i16:16:16-i32:32:32-i64:64:64-f32:32:32-f64:64:64-v64:64:64-v128:128:128-a0:0:64-s0:64:64-f80:128:128-n8:16:32:64-S128"
 target triple = "x86_64-unknown-linux-gnu"

diff --git a/llvm/test/Transforms/SimplifyCFG/X86/pr39187-g.ll b/llvm/test/Transforms/SimplifyCFG/X86/pr39187-g.ll
@@ -1,4 +1,4 @@
-; RUN: opt < %s -S -simplifycfg -hoist-common-insts=true | FileCheck %s
+; RUN: opt < %s -S -simplifycfg -simplifycfg-require-and-preserve-domtree=1 -hoist-common-insts=true | FileCheck %s
 
 ; SimplifyCFG can hoist any common code in the 'then' and 'else' blocks to
 ; the 'if' basic block.

diff --git a/llvm/test/Transforms/SimplifyCFG/X86/safe-low-bit-extract.ll b/llvm/test/Transforms/SimplifyCFG/X86/safe-low-bit-extract.ll
@@ -1,5 +1,5 @@
 ; NOTE: Assertions have been autogenerated by utils/update_test_checks.py
-; RUN: opt < %s -simplifycfg -S | FileCheck %s
+; RUN: opt < %s -simplifycfg -simplifycfg-require-and-preserve-domtree=1 -S | FileCheck %s
 
 ; This is the naive implementation of x86 BZHI/BEXTR instruction:
 ; it takes input and bit count, and extracts low nbits up to bit width.

diff --git a/llvm/test/Transforms/SimplifyCFG/X86/speculate-cttz-ctlz.ll b/llvm/test/Transforms/SimplifyCFG/X86/speculate-cttz-ctlz.ll
@@ -1,7 +1,7 @@
 ; NOTE: Assertions have been autogenerated by utils/update_test_checks.py
-; RUN: opt -S -simplifycfg -mtriple=x86_64-unknown-unknown -mattr=+bmi < %s | FileCheck %s --check-prefix=ALL --check-prefix=BMI
-; RUN: opt -S -simplifycfg -mtriple=x86_64-unknown-unknown -mattr=+lzcnt < %s | FileCheck %s --check-prefix=ALL --check-prefix=LZCNT
-; RUN: opt -S -simplifycfg -mtriple=x86_64-unknown-unknown < %s | FileCheck %s --check-prefix=ALL --check-prefix=GENERIC
+; RUN: opt -S -simplifycfg -simplifycfg-require-and-preserve-domtree=1 -mtriple=x86_64-unknown-unknown -mattr=+bmi < %s | FileCheck %s --check-prefix=ALL --check-prefix=BMI
+; RUN: opt -S -simplifycfg -simplifycfg-require-and-preserve-domtree=1 -mtriple=x86_64-unknown-unknown -mattr=+lzcnt < %s | FileCheck %s --check-prefix=ALL --check-prefix=LZCNT
+; RUN: opt -S -simplifycfg -simplifycfg-require-and-preserve-domtree=1 -mtriple=x86_64-unknown-unknown < %s | FileCheck %s --check-prefix=ALL --check-prefix=GENERIC
 
 
 define i64 @test1(i64 %A) {

diff --git a/llvm/test/Transforms/SimplifyCFG/X86/switch-covered-bug.ll b/llvm/test/Transforms/SimplifyCFG/X86/switch-covered-bug.ll
@@ -1,5 +1,5 @@
 ; NOTE: Assertions have been autogenerated by utils/update_test_checks.py
-; RUN: opt -S -simplifycfg -switch-to-lookup < %s -mtriple=x86_64-apple-darwin12.0.0 | FileCheck %s
+; RUN: opt -S -simplifycfg -simplifycfg-require-and-preserve-domtree=1 -switch-to-lookup < %s -mtriple=x86_64-apple-darwin12.0.0 | FileCheck %s
 ; RUN: opt -S -passes='simplify-cfg<switch-to-lookup>' < %s -mtriple=x86_64-apple-darwin12.0.0 | FileCheck %s
 
 ; rdar://17887153

diff --git a/llvm/test/Transforms/SimplifyCFG/X86/switch-table-bug.ll b/llvm/test/Transforms/SimplifyCFG/X86/switch-table-bug.ll
@@ -1,5 +1,5 @@
 ; NOTE: Assertions have been autogenerated by utils/update_test_checks.py
-; RUN: opt -S -simplifycfg -switch-to-lookup < %s -mtriple=x86_64-apple-darwin12.0.0 | FileCheck %s
+; RUN: opt -S -simplifycfg -simplifycfg-require-and-preserve-domtree=1 -switch-to-lookup < %s -mtriple=x86_64-apple-darwin12.0.0 | FileCheck %s
 ; RUN: opt -S -passes='simplify-cfg<switch-to-lookup>' < %s -mtriple=x86_64-apple-darwin12.0.0 | FileCheck %s
 
 ; rdar://17735071

diff --git a/llvm/test/Transforms/SimplifyCFG/annotations.ll b/llvm/test/Transforms/SimplifyCFG/annotations.ll
@@ -1,4 +1,4 @@
-; RUN: opt -simplifycfg -S %s | FileCheck --match-full-lines %s
+; RUN: opt -simplifycfg -simplifycfg-require-and-preserve-domtree=1 -S %s | FileCheck --match-full-lines %s
 
 ; The branch in %cont has !annotation metadata. Make sure generated AND
 ; has !annotation metadata.

diff --git a/llvm/test/Transforms/SimplifyCFG/basictest.ll b/llvm/test/Transforms/SimplifyCFG/basictest.ll
@@ -1,6 +1,6 @@
 ; Test CFG simplify removal of branch instructions.
 ;
-; RUN: opt < %s -simplifycfg -S | FileCheck %s
+; RUN: opt < %s -simplifycfg -simplifycfg-require-and-preserve-domtree=1 -S | FileCheck %s
 ; RUN: opt < %s -passes=simplify-cfg -S | FileCheck %s
 
 define void @test1() {

diff --git a/llvm/test/Transforms/SimplifyCFG/bbi-23595.ll b/llvm/test/Transforms/SimplifyCFG/bbi-23595.ll
@@ -1,4 +1,4 @@
-; RUN: opt < %s -S -simplifycfg | FileCheck %s
+; RUN: opt < %s -S -simplifycfg -simplifycfg-require-and-preserve-domtree=1 | FileCheck %s
 
 ; In 'simplifycfg', during the flattening of a 'br', the instructions for the
 ; 'true' and 'false' parts, are moved out from their respective basic blocks.

diff --git a/llvm/test/Transforms/SimplifyCFG/branch-fold-dbg.ll b/llvm/test/Transforms/SimplifyCFG/branch-fold-dbg.ll
@@ -1,4 +1,4 @@
-; RUN: opt -simplifycfg -S < %s | FileCheck %s
+; RUN: opt -simplifycfg -simplifycfg-require-and-preserve-domtree=1 -S < %s | FileCheck %s
 
 %0 = type { i32*, i32* }
 

diff --git a/llvm/test/Transforms/SimplifyCFG/branch-fold-threshold.ll b/llvm/test/Transforms/SimplifyCFG/branch-fold-threshold.ll
@@ -1,6 +1,6 @@
-; RUN: opt %s -simplifycfg -S | FileCheck %s --check-prefix=NORMAL
-; RUN: opt %s -simplifycfg -S -bonus-inst-threshold=2 | FileCheck %s --check-prefix=AGGRESSIVE
-; RUN: opt %s -simplifycfg -S -bonus-inst-threshold=4 | FileCheck %s --check-prefix=WAYAGGRESSIVE
+; RUN: opt %s -simplifycfg -simplifycfg-require-and-preserve-domtree=1 -S | FileCheck %s --check-prefix=NORMAL
+; RUN: opt %s -simplifycfg -simplifycfg-require-and-preserve-domtree=1 -S -bonus-inst-threshold=2 | FileCheck %s --check-prefix=AGGRESSIVE
+; RUN: opt %s -simplifycfg -simplifycfg-require-and-preserve-domtree=1 -S -bonus-inst-threshold=4 | FileCheck %s --check-prefix=WAYAGGRESSIVE
 ; RUN: opt %s -passes=simplify-cfg -S | FileCheck %s --check-prefix=NORMAL
 ; RUN: opt %s -passes='simplify-cfg<bonus-inst-threshold=2>' -S | FileCheck %s --check-prefix=AGGRESSIVE
 ; RUN: opt %s -passes='simplify-cfg<bonus-inst-threshold=4>' -S | FileCheck %s --check-prefix=WAYAGGRESSIVE

diff --git a/llvm/test/Transforms/SimplifyCFG/branch-fold.ll b/llvm/test/Transforms/SimplifyCFG/branch-fold.ll
@@ -1,4 +1,4 @@
-; RUN: opt < %s -simplifycfg -S | FileCheck %s
+; RUN: opt < %s -simplifycfg -simplifycfg-require-and-preserve-domtree=1 -S | FileCheck %s
 
 define void @test(i32* %P, i32* %Q, i1 %A, i1 %B) {
 ; CHECK: test

diff --git a/llvm/test/Transforms/SimplifyCFG/clamp.ll b/llvm/test/Transforms/SimplifyCFG/clamp.ll
@@ -1,4 +1,4 @@
-; RUN: opt < %s -simplifycfg -S | FileCheck %s
+; RUN: opt < %s -simplifycfg -simplifycfg-require-and-preserve-domtree=1 -S | FileCheck %s
 
 define float @clamp(float %a, float %b, float %c) {
 ; CHECK-LABEL: @clamp

diff --git a/llvm/test/Transforms/SimplifyCFG/common-dest-folding.ll b/llvm/test/Transforms/SimplifyCFG/common-dest-folding.ll
@@ -1,4 +1,4 @@
-; RUN: opt < %s -simplifycfg -S | FileCheck %s
+; RUN: opt < %s -simplifycfg -simplifycfg-require-and-preserve-domtree=1 -S | FileCheck %s
 
 ;CHECK: @foo
 ;CHECK: and i32 %c1, %k

diff --git a/llvm/test/Transforms/SimplifyCFG/empty-catchpad.ll b/llvm/test/Transforms/SimplifyCFG/empty-catchpad.ll
@@ -1,4 +1,4 @@
-; RUN: opt < %s -simplifycfg -S | FileCheck %s
+; RUN: opt < %s -simplifycfg -simplifycfg-require-and-preserve-domtree=1 -S | FileCheck %s
 
 declare void @f()
 declare void @llvm.foo(i32) nounwind

diff --git a/llvm/test/Transforms/SimplifyCFG/fold-debug-info.ll b/llvm/test/Transforms/SimplifyCFG/fold-debug-info.ll
@@ -1,6 +1,6 @@
 ;; Check that we don't crash. PR37300.
 ; NOTE: Assertions have been autogenerated by utils/update_test_checks.py
-; RUN: opt %s -S -simplifycfg | FileCheck %s
+; RUN: opt %s -S -simplifycfg -simplifycfg-require-and-preserve-domtree=1 | FileCheck %s
 
 define void @patatino() {
 ; CHECK-LABEL: @patatino(

diff --git a/llvm/test/Transforms/SimplifyCFG/fold-debug-location.ll b/llvm/test/Transforms/SimplifyCFG/fold-debug-location.ll
@@ -1,4 +1,4 @@
-; RUN: opt -S -simplifycfg < %s | FileCheck %s --match-full-lines
+; RUN: opt -S -simplifycfg -simplifycfg-require-and-preserve-domtree=1 < %s | FileCheck %s --match-full-lines
 
 ; Make sure we reset the debug location when folding instructions.
 ; CHECK: [[VAL:%.*]] = and i32 %c2, %k

diff --git a/llvm/test/Transforms/SimplifyCFG/hoist-common-code.ll b/llvm/test/Transforms/SimplifyCFG/hoist-common-code.ll
@@ -1,4 +1,4 @@
-; RUN: opt < %s -simplifycfg -S -hoist-common-insts=true | not grep br
+; RUN: opt < %s -simplifycfg -simplifycfg-require-and-preserve-domtree=1 -S -hoist-common-insts=true | not grep br
 
 declare void @bar(i32)
 

diff --git a/llvm/test/Transforms/SimplifyCFG/hoist-dbgvalue-inlined.ll b/llvm/test/Transforms/SimplifyCFG/hoist-dbgvalue-inlined.ll
@@ -1,4 +1,4 @@
-; RUN: opt -simplifycfg -hoist-common-insts=true -S < %s | FileCheck %s
+; RUN: opt -simplifycfg -simplifycfg-require-and-preserve-domtree=1 -hoist-common-insts=true -S < %s | FileCheck %s
 ; Verify that we don't crash due an invalid !dbg location on the hoisted llvm.dbg.value
 
 define i64 @caller(i64* %ptr, i64 %flag) !dbg !10 {

diff --git a/llvm/test/Transforms/SimplifyCFG/hoist-with-range.ll b/llvm/test/Transforms/SimplifyCFG/hoist-with-range.ll
@@ -1,4 +1,4 @@
-; RUN: opt < %s -simplifycfg -hoist-common-insts=true -S | FileCheck %s
+; RUN: opt < %s -simplifycfg -simplifycfg-require-and-preserve-domtree=1 -hoist-common-insts=true -S | FileCheck %s
 
 define void @foo(i1 %c, i8* %p) {
 ; CHECK: if:

diff --git a/llvm/test/Transforms/SimplifyCFG/implied-cond-matching-false-dest.ll b/llvm/test/Transforms/SimplifyCFG/implied-cond-matching-false-dest.ll
@@ -1,4 +1,4 @@
-; RUN: opt %s -S -simplifycfg | FileCheck %s
+; RUN: opt %s -S -simplifycfg -simplifycfg-require-and-preserve-domtree=1 | FileCheck %s
 
 declare void @is(i1)
 

diff --git a/llvm/test/Transforms/SimplifyCFG/implied-cond-matching.ll b/llvm/test/Transforms/SimplifyCFG/implied-cond-matching.ll
@@ -1,4 +1,4 @@
-; RUN: opt %s -S -simplifycfg | FileCheck %s
+; RUN: opt %s -S -simplifycfg -simplifycfg-require-and-preserve-domtree=1 | FileCheck %s
 
 declare void @dead()
 declare void @alive()

diff --git a/llvm/test/Transforms/SimplifyCFG/implied-cond.ll b/llvm/test/Transforms/SimplifyCFG/implied-cond.ll
@@ -1,4 +1,4 @@
-; RUN: opt %s -S -simplifycfg | FileCheck %s
+; RUN: opt %s -S -simplifycfg -simplifycfg-require-and-preserve-domtree=1 | FileCheck %s
 ; Check for when one branch implies the value of a successors conditional and
 ; it's not simply the same conditional repeated.
 

diff --git a/llvm/test/Transforms/SimplifyCFG/indirectbr.ll b/llvm/test/Transforms/SimplifyCFG/indirectbr.ll
@@ -1,4 +1,4 @@
-; RUN: opt -S -simplifycfg < %s | FileCheck %s
+; RUN: opt -S -simplifycfg -simplifycfg-require-and-preserve-domtree=1 < %s | FileCheck %s
 
 ; SimplifyCFG should eliminate redundant indirectbr edges.
 

diff --git a/llvm/test/Transforms/SimplifyCFG/invoke_unwind_lifetime.ll b/llvm/test/Transforms/SimplifyCFG/invoke_unwind_lifetime.ll
@@ -1,5 +1,5 @@
 ; NOTE: Assertions have been autogenerated by utils/update_test_checks.py
-; RUN: opt < %s -simplifycfg -S | FileCheck %s
+; RUN: opt < %s -simplifycfg -simplifycfg-require-and-preserve-domtree=1 -S | FileCheck %s
 
 declare void @llvm.lifetime.start.p0i8(i64, i8*)
 declare void @llvm.lifetime.end.p0i8(i64, i8*)

diff --git a/llvm/test/Transforms/SimplifyCFG/no-md-sink.ll b/llvm/test/Transforms/SimplifyCFG/no-md-sink.ll
@@ -1,4 +1,4 @@
-; RUN: opt < %s -simplifycfg -sink-common-insts -S | FileCheck %s
+; RUN: opt < %s -simplifycfg -simplifycfg-require-and-preserve-domtree=1 -sink-common-insts -S | FileCheck %s
 ; RUN: opt < %s -passes='simplify-cfg<sink-common-insts>' -S | FileCheck %s
 
 define i1 @test1(i1 zeroext %flag, i8* %y) #0 {

diff --git a/llvm/test/Transforms/SimplifyCFG/opt-for-fuzzing.ll b/llvm/test/Transforms/SimplifyCFG/opt-for-fuzzing.ll
@@ -1,4 +1,4 @@
-; RUN: opt < %s -simplifycfg -S | FileCheck %s
+; RUN: opt < %s -simplifycfg -simplifycfg-require-and-preserve-domtree=1 -S | FileCheck %s
 ; RUN: opt < %s -passes=simplifycfg -S | FileCheck %s
 
 define i32 @foo(i32 %x) optforfuzzing {

diff --git a/llvm/test/Transforms/SimplifyCFG/pr39807.ll b/llvm/test/Transforms/SimplifyCFG/pr39807.ll
@@ -1,4 +1,4 @@
-; RUN: opt -S -simplifycfg -hoist-common-insts=true < %s | FileCheck %s
+; RUN: opt -S -simplifycfg -simplifycfg-require-and-preserve-domtree=1 -hoist-common-insts=true < %s | FileCheck %s
 
 declare void @personality()
 

diff --git a/llvm/test/Transforms/SimplifyCFG/preserve-branchweights.ll b/llvm/test/Transforms/SimplifyCFG/preserve-branchweights.ll
@@ -1,5 +1,5 @@
 ; NOTE: Assertions have been autogenerated by utils/update_test_checks.py
-; RUN: opt -simplifycfg -S -o - < %s | FileCheck %s
+; RUN: opt -simplifycfg -simplifycfg-require-and-preserve-domtree=1 -S -o - < %s | FileCheck %s
 
 declare void @helper(i32)
 

diff --git a/llvm/test/Transforms/SimplifyCFG/rangereduce.ll b/llvm/test/Transforms/SimplifyCFG/rangereduce.ll
@@ -1,5 +1,5 @@
 ; NOTE: Assertions have been autogenerated by utils/update_test_checks.py
-; RUN: opt < %s -simplifycfg -switch-to-lookup -S | FileCheck %s
+; RUN: opt < %s -simplifycfg -simplifycfg-require-and-preserve-domtree=1 -switch-to-lookup -S | FileCheck %s
 ; RUN: opt < %s -passes='simplify-cfg<switch-to-lookup>' -S | FileCheck %s
 
 target datalayout = "e-n32"

diff --git a/llvm/test/Transforms/SimplifyCFG/safe-abs.ll b/llvm/test/Transforms/SimplifyCFG/safe-abs.ll
@@ -1,5 +1,5 @@
 ; NOTE: Assertions have been autogenerated by utils/update_test_checks.py
-; RUN: opt < %s -simplifycfg -S | FileCheck %s
+; RUN: opt < %s -simplifycfg -simplifycfg-require-and-preserve-domtree=1 -S | FileCheck %s
 
 ; Reduced from arm_abs_q31() from CMSIS DSP suite.
 ; https://reviews.llvm.org/D65148#1629010

diff --git a/llvm/test/Transforms/SimplifyCFG/signbit-like-value-extension.ll b/llvm/test/Transforms/SimplifyCFG/signbit-like-value-extension.ll
@@ -1,5 +1,5 @@
 ; NOTE: Assertions have been autogenerated by utils/update_test_checks.py
-; RUN: opt < %s -simplifycfg -S | FileCheck %s
+; RUN: opt < %s -simplifycfg -simplifycfg-require-and-preserve-domtree=1 -S | FileCheck %s
 
 ; This looks like a normal sign extension, but it's not.
 ; This comes up in JPEG decoding. This check is really unpredictable,

diff --git a/llvm/test/Transforms/SimplifyCFG/speculate-math.ll b/llvm/test/Transforms/SimplifyCFG/speculate-math.ll
@@ -1,6 +1,6 @@
 ; NOTE: Assertions have been autogenerated by utils/update_test_checks.py
-; RUN: opt -S -simplifycfg < %s | FileCheck %s
-; RUN: opt -S -simplifycfg -speculate-one-expensive-inst=false < %s | FileCheck %s
+; RUN: opt -S -simplifycfg -simplifycfg-require-and-preserve-domtree=1 < %s | FileCheck %s
+; RUN: opt -S -simplifycfg -simplifycfg-require-and-preserve-domtree=1 -speculate-one-expensive-inst=false < %s | FileCheck %s
 
 declare float @llvm.sqrt.f32(float) nounwind readonly
 declare float @llvm.fma.f32(float, float, float) nounwind readonly

diff --git a/llvm/test/Transforms/SimplifyCFG/speculate-with-offset.ll b/llvm/test/Transforms/SimplifyCFG/speculate-with-offset.ll
@@ -1,4 +1,4 @@
-; RUN: opt -simplifycfg -S < %s | FileCheck %s
+; RUN: opt -simplifycfg -simplifycfg-require-and-preserve-domtree=1 -S < %s | FileCheck %s
 
 ; This load is safe to speculate, as it's from a safe offset
 ; within an alloca.

diff --git a/llvm/test/Transforms/SimplifyCFG/switch-masked-bits.ll b/llvm/test/Transforms/SimplifyCFG/switch-masked-bits.ll
@@ -1,5 +1,5 @@
 ; NOTE: Assertions have been autogenerated by utils/update_test_checks.py
-; RUN: opt -S -simplifycfg < %s | FileCheck %s
+; RUN: opt -S -simplifycfg -simplifycfg-require-and-preserve-domtree=1 < %s | FileCheck %s
 
 define i32 @test1(i32 %x) nounwind {
 ; CHECK-LABEL: @test1(

diff --git a/llvm/test/Transforms/SimplifyCFG/switch-on-const-select.ll b/llvm/test/Transforms/SimplifyCFG/switch-on-const-select.ll
@@ -1,5 +1,5 @@
 ; NOTE: Assertions have been autogenerated by utils/update_test_checks.py
-; RUN: opt < %s -simplifycfg -S | FileCheck -enable-var-scope %s
+; RUN: opt < %s -simplifycfg -simplifycfg-require-and-preserve-domtree=1 -S | FileCheck -enable-var-scope %s
 
 ; Test basic folding to a conditional branch.
 define i32 @foo(i64 %x, i64 %y) nounwind {

diff --git a/llvm/test/Transforms/SimplifyCFG/switch-profmd.ll b/llvm/test/Transforms/SimplifyCFG/switch-profmd.ll
@@ -1,4 +1,4 @@
-; RUN: opt -S -simplifycfg < %s | FileCheck %s
+; RUN: opt -S -simplifycfg -simplifycfg-require-and-preserve-domtree=1 < %s | FileCheck %s
 
 declare i32 @f(i32 %val)
 

diff --git a/llvm/test/Transforms/SimplifyCFG/switch-range-to-icmp.ll b/llvm/test/Transforms/SimplifyCFG/switch-range-to-icmp.ll
@@ -1,5 +1,5 @@
 ; NOTE: Assertions have been autogenerated by utils/update_test_checks.py
-; RUN: opt %s -simplifycfg -S | FileCheck %s
+; RUN: opt %s -simplifycfg -simplifycfg-require-and-preserve-domtree=1 -S | FileCheck %s
 
 declare i32 @f(i32)
 

diff --git a/llvm/test/Transforms/SimplifyCFG/switch-simplify-crash.ll b/llvm/test/Transforms/SimplifyCFG/switch-simplify-crash.ll
@@ -1,4 +1,4 @@
-; RUN: opt < %s -simplifycfg -disable-output
+; RUN: opt < %s -simplifycfg -simplifycfg-require-and-preserve-domtree=1 -disable-output
 
 define void @NewExtractNames() {
 entry:

diff --git a/llvm/test/Transforms/SimplifyCFG/switch-to-icmp.ll b/llvm/test/Transforms/SimplifyCFG/switch-to-icmp.ll
@@ -1,4 +1,4 @@
-; RUN: opt -S -simplifycfg < %s | FileCheck %s
+; RUN: opt -S -simplifycfg -simplifycfg-require-and-preserve-domtree=1 < %s | FileCheck %s
 
 define zeroext i1 @test1(i32 %x) nounwind readnone ssp noredzone {
 entry:

diff --git a/llvm/test/Transforms/SimplifyCFG/switch-to-select-two-case.ll b/llvm/test/Transforms/SimplifyCFG/switch-to-select-two-case.ll
@@ -1,4 +1,4 @@
-; RUN: opt < %s -simplifycfg -S | FileCheck %s
+; RUN: opt < %s -simplifycfg -simplifycfg-require-and-preserve-domtree=1 -S | FileCheck %s
 
 ; int foo1_with_default(int a) {
 ;   switch(a) {

diff --git a/llvm/test/Transforms/SimplifyCFG/switch_switch_fold.ll b/llvm/test/Transforms/SimplifyCFG/switch_switch_fold.ll
@@ -1,5 +1,5 @@
 ; NOTE: Assertions have been autogenerated by utils/update_test_checks.py
-; RUN: opt < %s -simplifycfg -S | FileCheck %s
+; RUN: opt < %s -simplifycfg -simplifycfg-require-and-preserve-domtree=1 -S | FileCheck %s
 
 ; Test that a switch going to a switch on the same value can be merged.
 ; All three switches in this example can be merged into one big one.

diff --git a/llvm/test/Transforms/SimplifyCFG/switch_thread.ll b/llvm/test/Transforms/SimplifyCFG/switch_thread.ll
@@ -1,5 +1,5 @@
 ; NOTE: Assertions have been autogenerated by utils/update_test_checks.py
-; RUN: opt < %s -simplifycfg -S | FileCheck %s
+; RUN: opt < %s -simplifycfg -simplifycfg-require-and-preserve-domtree=1 -S | FileCheck %s
 
 ; Test that we can thread a simple known condition through switch statements.
 

diff --git a/llvm/test/Transforms/SimplifyCFG/unreachable_assume.ll b/llvm/test/Transforms/SimplifyCFG/unreachable_assume.ll
@@ -1,5 +1,5 @@
 ; NOTE: Assertions have been autogenerated by utils/update_test_checks.py
-; RUN: opt %s -simplifycfg -instcombine -S | FileCheck %s
+; RUN: opt %s -simplifycfg -simplifycfg-require-and-preserve-domtree=1 -instcombine -S | FileCheck %s
 
 define i32 @assume1(i32 %p) {
 ; CHECK-LABEL: @assume1(

diff --git a/llvm/test/Transforms/SimplifyCFG/unsigned-multiplication-will-overflow.ll b/llvm/test/Transforms/SimplifyCFG/unsigned-multiplication-will-overflow.ll
@@ -1,7 +1,7 @@
 ; NOTE: Assertions have been autogenerated by utils/update_test_checks.py
-; RUN: opt < %s -simplifycfg -S | FileCheck %s
-; RUN: opt < %s -simplifycfg -phi-node-folding-threshold=2 -S | FileCheck %s
-; RUN: opt < %s -simplifycfg -phi-node-folding-threshold=3 -S | FileCheck %s
+; RUN: opt < %s -simplifycfg -simplifycfg-require-and-preserve-domtree=1 -S | FileCheck %s
+; RUN: opt < %s -simplifycfg -simplifycfg-require-and-preserve-domtree=1 -phi-node-folding-threshold=2 -S | FileCheck %s
+; RUN: opt < %s -simplifycfg -simplifycfg-require-and-preserve-domtree=1 -phi-node-folding-threshold=3 -S | FileCheck %s
 
 ; This is checking that the multiplication does overflow, with a leftover
 ; guard against division-by-zero that was needed before InstCombine

diff --git a/llvm/test/Transforms/SimplifyCFG/wineh-unreachable.ll b/llvm/test/Transforms/SimplifyCFG/wineh-unreachable.ll
@@ -1,4 +1,4 @@
-; RUN: opt -S -simplifycfg < %s | FileCheck %s
+; RUN: opt -S -simplifycfg -simplifycfg-require-and-preserve-domtree=1 < %s | FileCheck %s
 
 declare void @Personality()
 declare void @f()