[SimplifyCFG] ConstantFoldTerminator() already knows how to preserve DomTree

... so just ensure that we pass DomTreeUpdater it into it.

Fixes DomTree preservation for a number of tests,
all of which are marked as such so that they do not regress.

Author: LebedevRI

llvm/lib/Transforms/Utils/SimplifyCFG.cpp

@@ -6322,7 +6322,8 @@ bool SimplifyCFGOpt::simplifyOnce(BasicBlock *BB) {
 
   // Check to see if we can constant propagate this terminator instruction
   // away...
-  Changed |= ConstantFoldTerminator(BB, true);
+  Changed |= ConstantFoldTerminator(BB, /*DeleteDeadConditions=*/true,
+                                    /*TLI=*/nullptr, DTU);
 
   // Check for and eliminate duplicate PHI nodes in this block.
   Changed |= EliminateDuplicatePHINodes(BB);

llvm/test/Transforms/SimplifyCFG/2004-12-10-SimplifyCFGCrash.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 @symhash_add() {
 entry:

llvm/test/Transforms/SimplifyCFG/2008-09-08-MultiplePred.ll

@@ -1,4 +1,4 @@
-; RUN: opt < %s -simplifycfg -disable-output
+; RUN: opt < %s -simplifycfg -simplifycfg-require-and-preserve-domtree=1 -disable-output
 ; PR 2777
 @g_103 = common global i32 0		; <i32*> [#uses=1]
 

llvm/test/Transforms/SimplifyCFG/2011-03-08-UnreachableUse.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
 ; PR9420
 
 ; Note that the crash in PR9420 test is sensitive to the ordering of

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(

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)
 

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()

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.
 

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.