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
@@ -74,6 +74,7 @@
 
 STATISTIC(NumBranches, "Number of branches unswitched");
 STATISTIC(NumSwitches, "Number of switches unswitched");
+STATISTIC(NumSelects, "Number of selects turned into branches for unswitching");
 STATISTIC(NumGuards, "Number of guards turned into branches for unswitching");
 STATISTIC(NumTrivial, "Number of unswitches that are trivial");
 STATISTIC(
@@ -2642,6 +2643,59 @@
   return Cost;
 }
 
+/// Turns a select instruction into implicit control flow branch,
+/// making the following replacement:
+///
+/// head:
+///   --code before select--
+///   select %cond, %trueval, %falseval
+///   --code after select--
+///
+/// into
+///
+/// head:
+///   --code before select--
+///   br i1 %cond, label %then, label %tail
+///
+/// then:
+///   br %tail
+///
+/// tail:
+///   phi [ %trueval, %then ], [ %falseval, %head]
+///   unreachable
+///
+/// It also makes all relevant DT and LI updates, so that all structures are in
+/// valid state after this transform.
+static BranchInst *turnSelectIntoBranch(SelectInst *SI, DominatorTree &DT,
+                                        LoopInfo &LI, MemorySSAUpdater *MSSAU,
+                                        AssumptionCache *AC) {
+  LLVM_DEBUG(dbgs() << "Turning " << *SI << " into a branch.\n");
+  BasicBlock *HeadBB = SI->getParent();
+
+  Value *Cond = SI->getCondition();
+  if (!isGuaranteedNotToBeUndefOrPoison(Cond, AC, SI, &DT))
+    Cond = new FreezeInst(Cond, Cond->getName() + ".fr", SI);
+  SplitBlockAndInsertIfThen(SI->getCondition(), SI, false,
+                            SI->getMetadata(LLVMContext::MD_prof), &DT, &LI);
+  auto *CondBr = cast<BranchInst>(HeadBB->getTerminator());
+  BasicBlock *ThenBB = CondBr->getSuccessor(0),
+             *TailBB = CondBr->getSuccessor(1);
+  if (MSSAU)
+    MSSAU->moveAllAfterSpliceBlocks(HeadBB, TailBB, SI);
+
+  PHINode *Phi = PHINode::Create(SI->getType(), 2, "unswitched.select", SI);
+  Phi->addIncoming(SI->getTrueValue(), ThenBB);
+  Phi->addIncoming(SI->getFalseValue(), HeadBB);
+  SI->replaceAllUsesWith(Phi);
+  SI->eraseFromParent();
+
+  if (MSSAU && VerifyMemorySSA)
+    MSSAU->getMemorySSA()->verifyMemorySSA();
+
+  ++NumSelects;
+  return CondBr;
+}
+
 /// Turns a llvm.experimental.guard intrinsic into implicit control flow branch,
 /// making the following replacement:
 ///
@@ -2749,9 +2803,10 @@
   const BasicBlock *CondBlock = TI.getParent();
   if (DT.dominates(CondBlock, Latch) &&
       (isGuard(&TI) ||
-       llvm::count_if(successors(&TI), [&L](const BasicBlock *SuccBB) {
-         return L.contains(SuccBB);
-       }) <= 1)) {
+       (TI.isTerminator() &&
+        llvm::count_if(successors(&TI), [&L](const BasicBlock *SuccBB) {
+          return L.contains(SuccBB);
+        }) <= 1))) {
     NumCostMultiplierSkipped++;
     return 1;
   }
@@ -2760,12 +2815,17 @@
   int SiblingsCount = (ParentL ? ParentL->getSubLoopsVector().size()
                                : std::distance(LI.begin(), LI.end()));
   // Count amount of clones that all the candidates might cause during
-  // unswitching. Branch/guard counts as 1, switch counts as log2 of its cases.
+  // unswitching. Branch/guard/select counts as 1, switch counts as log2 of its
+  // cases.
   int UnswitchedClones = 0;
   for (auto Candidate : UnswitchCandidates) {
     const Instruction *CI = Candidate.TI;
     const BasicBlock *CondBlock = CI->getParent();
     bool SkipExitingSuccessors = DT.dominates(CondBlock, Latch);
+    if (isa<SelectInst>(CI)) {
+      UnswitchedClones++;
+      continue;
+    }
     if (isGuard(CI)) {
       if (!SkipExitingSuccessors)
         UnswitchedClones++;
@@ -2828,15 +2888,19 @@
     if (LI.getLoopFor(BB) != &L)
       continue;
 
-    if (CollectGuards)
-      for (auto &I : *BB)
-        if (isGuard(&I)) {
-          auto *Cond =
-              skipTrivialSelect(cast<IntrinsicInst>(&I)->getArgOperand(0));
-          // TODO: Support AND, OR conditions and partial unswitching.
-          if (!isa<Constant>(Cond) && L.isLoopInvariant(Cond))
-            UnswitchCandidates.push_back({&I, {Cond}});
-        }
+    for (auto &I : *BB) {
+      if (auto *SI = dyn_cast<SelectInst>(&I)) {
+        auto *Cond = SI->getCondition();
+        if (!isa<Constant>(Cond) && L.isLoopInvariant(Cond))
+          UnswitchCandidates.push_back({&I, {Cond}});
+      } else if (CollectGuards && isGuard(&I)) {
+        auto *Cond =
+            skipTrivialSelect(cast<IntrinsicInst>(&I)->getArgOperand(0));
+        // TODO: Support AND, OR conditions and partial unswitching.
+        if (!isa<Constant>(Cond) && L.isLoopInvariant(Cond))
+          UnswitchCandidates.push_back({&I, {Cond}});
+      }
+    }
 
     if (auto *SI = dyn_cast<SwitchInst>(BB->getTerminator())) {
       // We can only consider fully loop-invariant switch conditions as we need
@@ -3338,7 +3402,8 @@
     // loop. This is computing the new cost of unswitching a condition.
     // Note that guards always have 2 unique successors that are implicit and
     // will be materialized if we decide to unswitch it.
-    int SuccessorsCount = isGuard(&TI) ? 2 : Visited.size();
+    int SuccessorsCount =
+        isGuard(&TI) || isa<SelectInst>(TI) ? 2 : Visited.size();
     assert(SuccessorsCount > 1 &&
            "Cannot unswitch a condition without multiple distinct successors!");
     return (LoopCost - Cost) * (SuccessorsCount - 1);
@@ -3425,7 +3490,9 @@
     PartialIVInfo.InstToDuplicate.clear();
 
   // If the best candidate is a guard, turn it into a branch.
-  if (isGuard(Best.TI))
+  if (auto *SI = dyn_cast<SelectInst>(Best.TI))
+    Best.TI = turnSelectIntoBranch(SI, DT, LI, MSSAU, &AC);
+  else if (isGuard(Best.TI))
     Best.TI =
         turnGuardIntoBranch(cast<IntrinsicInst>(Best.TI), L, DT, LI, MSSAU);
 
diff --git a/llvm/test/Transforms/SimpleLoopUnswitch/nontrivial-unswitch-freeze.ll b/llvm/test/Transforms/SimpleLoopUnswitch/nontrivial-unswitch-freeze.ll
--- a/llvm/test/Transforms/SimpleLoopUnswitch/nontrivial-unswitch-freeze.ll
+++ b/llvm/test/Transforms/SimpleLoopUnswitch/nontrivial-unswitch-freeze.ll
@@ -2332,21 +2332,26 @@
 define i32 @test_partial_unswitch_all_conds_guaranteed_non_poison(i1 noundef %c.1, i1 noundef %c.2) {
 ; CHECK-LABEL: @test_partial_unswitch_all_conds_guaranteed_non_poison(
 ; CHECK-NEXT:  entry:
-; CHECK-NEXT:    [[TMP0:%.*]] = and i1 [[C_1:%.*]], [[C_2:%.*]]
-; CHECK-NEXT:    br i1 [[TMP0]], label [[ENTRY_SPLIT:%.*]], label [[ENTRY_SPLIT_US:%.*]]
+; CHECK-NEXT:    br i1 [[C_1:%.*]], label [[ENTRY_SPLIT_US:%.*]], label [[ENTRY_SPLIT:%.*]]
 ; CHECK:       entry.split.us:
 ; CHECK-NEXT:    br label [[LOOP_US:%.*]]
 ; CHECK:       loop.us:
-; CHECK-NEXT:    [[TMP1:%.*]] = call i32 @a()
-; CHECK-NEXT:    br label [[EXIT_SPLIT_US:%.*]]
+; CHECK-NEXT:    [[TMP0:%.*]] = call i32 @a()
+; CHECK-NEXT:    br label [[TMP1:%.*]]
+; CHECK:       1:
+; CHECK-NEXT:    br label [[TMP2:%.*]]
+; CHECK:       2:
+; CHECK-NEXT:    [[UNSWITCHED_SELECT_US:%.*]] = phi i1 [ [[C_2:%.*]], [[TMP1]] ]
+; CHECK-NEXT:    br i1 [[UNSWITCHED_SELECT_US]], label [[LOOP_US]], label [[EXIT_SPLIT_US:%.*]]
 ; CHECK:       exit.split.us:
 ; CHECK-NEXT:    br label [[EXIT:%.*]]
 ; CHECK:       entry.split:
 ; CHECK-NEXT:    br label [[LOOP:%.*]]
 ; CHECK:       loop:
-; CHECK-NEXT:    [[TMP2:%.*]] = call i32 @a()
-; CHECK-NEXT:    [[SEL:%.*]] = select i1 true, i1 true, i1 false
-; CHECK-NEXT:    br i1 [[SEL]], label [[LOOP]], label [[EXIT_SPLIT:%.*]]
+; CHECK-NEXT:    [[TMP3:%.*]] = call i32 @a()
+; CHECK-NEXT:    br label [[TMP4:%.*]]
+; CHECK:       4:
+; CHECK-NEXT:    br i1 false, label [[LOOP]], label [[EXIT_SPLIT:%.*]]
 ; CHECK:       exit.split:
 ; CHECK-NEXT:    br label [[EXIT]]
 ; CHECK:       exit:
diff --git a/llvm/test/Transforms/SimpleLoopUnswitch/nontrivial-unswitch-select.ll b/llvm/test/Transforms/SimpleLoopUnswitch/nontrivial-unswitch-select.ll
--- a/llvm/test/Transforms/SimpleLoopUnswitch/nontrivial-unswitch-select.ll
+++ b/llvm/test/Transforms/SimpleLoopUnswitch/nontrivial-unswitch-select.ll
@@ -10,20 +10,48 @@
 ; CHECK-LABEL: define i32 @basic
 ; CHECK-SAME: (i32 [[N:%.*]], i1 [[COND:%.*]], i32 [[SELECT_INPUT:%.*]]) {
 ; CHECK-NEXT:  entry:
+; CHECK-NEXT:    [[COND_FR1:%.*]] = freeze i1 [[COND]]
+; CHECK-NEXT:    br i1 [[COND_FR1]], label [[ENTRY_SPLIT_US:%.*]], label [[ENTRY_SPLIT:%.*]]
+; CHECK:       entry.split.us:
+; CHECK-NEXT:    br label [[FOR_COND_US:%.*]]
+; CHECK:       for.cond.us:
+; CHECK-NEXT:    [[RES_US:%.*]] = phi i32 [ 0, [[ENTRY_SPLIT_US]] ], [ [[ADD_US:%.*]], [[TMP1:%.*]] ]
+; CHECK-NEXT:    [[I_US:%.*]] = phi i32 [ 0, [[ENTRY_SPLIT_US]] ], [ [[INC_US:%.*]], [[TMP1]] ]
+; CHECK-NEXT:    [[CMP_US:%.*]] = icmp slt i32 [[I_US]], [[N]]
+; CHECK-NEXT:    br i1 [[CMP_US]], label [[FOR_BODY_US:%.*]], label [[FOR_COND_CLEANUP_SPLIT_US:%.*]]
+; CHECK:       for.body.us:
+; CHECK-NEXT:    [[COND_FR_US:%.*]] = freeze i1 true
+; CHECK-NEXT:    br label [[TMP0:%.*]]
+; CHECK:       0:
+; CHECK-NEXT:    br label [[TMP1]]
+; CHECK:       1:
+; CHECK-NEXT:    [[UNSWITCHED_SELECT_US:%.*]] = phi i32 [ [[SELECT_INPUT]], [[TMP0]] ]
+; CHECK-NEXT:    [[ADD_US]] = add nuw nsw i32 [[UNSWITCHED_SELECT_US]], [[RES_US]]
+; CHECK-NEXT:    [[INC_US]] = add nuw nsw i32 [[I_US]], 1
+; CHECK-NEXT:    br label [[FOR_COND_US]]
+; CHECK:       for.cond.cleanup.split.us:
+; CHECK-NEXT:    [[RES_LCSSA_US:%.*]] = phi i32 [ [[RES_US]], [[FOR_COND_US]] ]
+; CHECK-NEXT:    br label [[FOR_COND_CLEANUP:%.*]]
+; CHECK:       entry.split:
 ; CHECK-NEXT:    br label [[FOR_COND:%.*]]
 ; CHECK:       for.cond:
-; CHECK-NEXT:    [[RES:%.*]] = phi i32 [ 0, [[ENTRY:%.*]] ], [ [[ADD:%.*]], [[FOR_BODY:%.*]] ]
-; CHECK-NEXT:    [[I:%.*]] = phi i32 [ 0, [[ENTRY]] ], [ [[INC:%.*]], [[FOR_BODY]] ]
+; CHECK-NEXT:    [[RES:%.*]] = phi i32 [ 0, [[ENTRY_SPLIT]] ], [ [[ADD:%.*]], [[TMP2:%.*]] ]
+; CHECK-NEXT:    [[I:%.*]] = phi i32 [ 0, [[ENTRY_SPLIT]] ], [ [[INC:%.*]], [[TMP2]] ]
 ; CHECK-NEXT:    [[CMP:%.*]] = icmp slt i32 [[I]], [[N]]
-; CHECK-NEXT:    br i1 [[CMP]], label [[FOR_BODY]], label [[FOR_COND_CLEANUP:%.*]]
+; CHECK-NEXT:    br i1 [[CMP]], label [[FOR_BODY:%.*]], label [[FOR_COND_CLEANUP_SPLIT:%.*]]
 ; CHECK:       for.body:
-; CHECK-NEXT:    [[COND1:%.*]] = select i1 [[COND]], i32 [[SELECT_INPUT]], i32 42
-; CHECK-NEXT:    [[ADD]] = add nuw nsw i32 [[COND1]], [[RES]]
+; CHECK-NEXT:    [[COND_FR:%.*]] = freeze i1 false
+; CHECK-NEXT:    br label [[TMP2]]
+; CHECK:       2:
+; CHECK-NEXT:    [[ADD]] = add nuw nsw i32 42, [[RES]]
 ; CHECK-NEXT:    [[INC]] = add nuw nsw i32 [[I]], 1
 ; CHECK-NEXT:    br label [[FOR_COND]]
-; CHECK:       for.cond.cleanup:
+; CHECK:       for.cond.cleanup.split:
 ; CHECK-NEXT:    [[RES_LCSSA:%.*]] = phi i32 [ [[RES]], [[FOR_COND]] ]
-; CHECK-NEXT:    ret i32 [[RES_LCSSA]]
+; CHECK-NEXT:    br label [[FOR_COND_CLEANUP]]
+; CHECK:       for.cond.cleanup:
+; CHECK-NEXT:    [[DOTUS_PHI:%.*]] = phi i32 [ [[RES_LCSSA]], [[FOR_COND_CLEANUP_SPLIT]] ], [ [[RES_LCSSA_US]], [[FOR_COND_CLEANUP_SPLIT_US]] ]
+; CHECK-NEXT:    ret i32 [[DOTUS_PHI]]
 ;
 entry:
   br label %for.cond
@@ -48,20 +76,48 @@
 ; CHECK-LABEL: define i32 @select_phi_input
 ; CHECK-SAME: (i32 [[N:%.*]], i1 [[COND:%.*]]) {
 ; CHECK-NEXT:  entry:
+; CHECK-NEXT:    [[COND_FR1:%.*]] = freeze i1 [[COND]]
+; CHECK-NEXT:    br i1 [[COND_FR1]], label [[ENTRY_SPLIT_US:%.*]], label [[ENTRY_SPLIT:%.*]]
+; CHECK:       entry.split.us:
+; CHECK-NEXT:    br label [[FOR_COND_US:%.*]]
+; CHECK:       for.cond.us:
+; CHECK-NEXT:    [[RES_US:%.*]] = phi i32 [ 0, [[ENTRY_SPLIT_US]] ], [ [[ADD_US:%.*]], [[TMP1:%.*]] ]
+; CHECK-NEXT:    [[I_US:%.*]] = phi i32 [ 0, [[ENTRY_SPLIT_US]] ], [ [[INC_US:%.*]], [[TMP1]] ]
+; CHECK-NEXT:    [[CMP_US:%.*]] = icmp slt i32 [[I_US]], [[N]]
+; CHECK-NEXT:    br i1 [[CMP_US]], label [[FOR_BODY_US:%.*]], label [[FOR_COND_CLEANUP_SPLIT_US:%.*]]
+; CHECK:       for.body.us:
+; CHECK-NEXT:    [[COND_FR_US:%.*]] = freeze i1 true
+; CHECK-NEXT:    br label [[TMP0:%.*]]
+; CHECK:       0:
+; CHECK-NEXT:    br label [[TMP1]]
+; CHECK:       1:
+; CHECK-NEXT:    [[UNSWITCHED_SELECT_US:%.*]] = phi i32 [ [[I_US]], [[TMP0]] ]
+; CHECK-NEXT:    [[ADD_US]] = add nuw nsw i32 [[UNSWITCHED_SELECT_US]], [[RES_US]]
+; CHECK-NEXT:    [[INC_US]] = add nuw nsw i32 [[I_US]], 1
+; CHECK-NEXT:    br label [[FOR_COND_US]]
+; CHECK:       for.cond.cleanup.split.us:
+; CHECK-NEXT:    [[RES_LCSSA_US:%.*]] = phi i32 [ [[RES_US]], [[FOR_COND_US]] ]
+; CHECK-NEXT:    br label [[FOR_COND_CLEANUP:%.*]]
+; CHECK:       entry.split:
 ; CHECK-NEXT:    br label [[FOR_COND:%.*]]
 ; CHECK:       for.cond:
-; CHECK-NEXT:    [[RES:%.*]] = phi i32 [ 0, [[ENTRY:%.*]] ], [ [[ADD:%.*]], [[FOR_BODY:%.*]] ]
-; CHECK-NEXT:    [[I:%.*]] = phi i32 [ 0, [[ENTRY]] ], [ [[INC:%.*]], [[FOR_BODY]] ]
+; CHECK-NEXT:    [[RES:%.*]] = phi i32 [ 0, [[ENTRY_SPLIT]] ], [ [[ADD:%.*]], [[TMP2:%.*]] ]
+; CHECK-NEXT:    [[I:%.*]] = phi i32 [ 0, [[ENTRY_SPLIT]] ], [ [[INC:%.*]], [[TMP2]] ]
 ; CHECK-NEXT:    [[CMP:%.*]] = icmp slt i32 [[I]], [[N]]
-; CHECK-NEXT:    br i1 [[CMP]], label [[FOR_BODY]], label [[FOR_COND_CLEANUP:%.*]]
+; CHECK-NEXT:    br i1 [[CMP]], label [[FOR_BODY:%.*]], label [[FOR_COND_CLEANUP_SPLIT:%.*]]
 ; CHECK:       for.body:
-; CHECK-NEXT:    [[COND1:%.*]] = select i1 [[COND]], i32 [[I]], i32 42
-; CHECK-NEXT:    [[ADD]] = add nuw nsw i32 [[COND1]], [[RES]]
+; CHECK-NEXT:    [[COND_FR:%.*]] = freeze i1 false
+; CHECK-NEXT:    br label [[TMP2]]
+; CHECK:       2:
+; CHECK-NEXT:    [[ADD]] = add nuw nsw i32 42, [[RES]]
 ; CHECK-NEXT:    [[INC]] = add nuw nsw i32 [[I]], 1
 ; CHECK-NEXT:    br label [[FOR_COND]]
-; CHECK:       for.cond.cleanup:
+; CHECK:       for.cond.cleanup.split:
 ; CHECK-NEXT:    [[RES_LCSSA:%.*]] = phi i32 [ [[RES]], [[FOR_COND]] ]
-; CHECK-NEXT:    ret i32 [[RES_LCSSA]]
+; CHECK-NEXT:    br label [[FOR_COND_CLEANUP]]
+; CHECK:       for.cond.cleanup:
+; CHECK-NEXT:    [[DOTUS_PHI:%.*]] = phi i32 [ [[RES_LCSSA]], [[FOR_COND_CLEANUP_SPLIT]] ], [ [[RES_LCSSA_US]], [[FOR_COND_CLEANUP_SPLIT_US]] ]
+; CHECK-NEXT:    ret i32 [[DOTUS_PHI]]
 ;
 entry:
   br label %for.cond
@@ -86,20 +142,45 @@
 ; CHECK-LABEL: define i32 @basic_cond_noundef
 ; CHECK-SAME: (i32 [[N:%.*]], i1 noundef [[COND:%.*]]) {
 ; CHECK-NEXT:  entry:
+; CHECK-NEXT:    br i1 [[COND]], label [[ENTRY_SPLIT_US:%.*]], label [[ENTRY_SPLIT:%.*]]
+; CHECK:       entry.split.us:
+; CHECK-NEXT:    br label [[FOR_COND_US:%.*]]
+; CHECK:       for.cond.us:
+; CHECK-NEXT:    [[RES_US:%.*]] = phi i32 [ 0, [[ENTRY_SPLIT_US]] ], [ [[ADD_US:%.*]], [[TMP1:%.*]] ]
+; CHECK-NEXT:    [[I_US:%.*]] = phi i32 [ 0, [[ENTRY_SPLIT_US]] ], [ [[INC_US:%.*]], [[TMP1]] ]
+; CHECK-NEXT:    [[CMP_US:%.*]] = icmp slt i32 [[I_US]], [[N]]
+; CHECK-NEXT:    br i1 [[CMP_US]], label [[FOR_BODY_US:%.*]], label [[FOR_COND_CLEANUP_SPLIT_US:%.*]]
+; CHECK:       for.body.us:
+; CHECK-NEXT:    br label [[TMP0:%.*]]
+; CHECK:       0:
+; CHECK-NEXT:    br label [[TMP1]]
+; CHECK:       1:
+; CHECK-NEXT:    [[UNSWITCHED_SELECT_US:%.*]] = phi i32 [ [[I_US]], [[TMP0]] ]
+; CHECK-NEXT:    [[ADD_US]] = add nuw nsw i32 [[UNSWITCHED_SELECT_US]], [[RES_US]]
+; CHECK-NEXT:    [[INC_US]] = add nuw nsw i32 [[I_US]], 1
+; CHECK-NEXT:    br label [[FOR_COND_US]]
+; CHECK:       for.cond.cleanup.split.us:
+; CHECK-NEXT:    [[RES_LCSSA_US:%.*]] = phi i32 [ [[RES_US]], [[FOR_COND_US]] ]
+; CHECK-NEXT:    br label [[FOR_COND_CLEANUP:%.*]]
+; CHECK:       entry.split:
 ; CHECK-NEXT:    br label [[FOR_COND:%.*]]
 ; CHECK:       for.cond:
-; CHECK-NEXT:    [[RES:%.*]] = phi i32 [ 0, [[ENTRY:%.*]] ], [ [[ADD:%.*]], [[FOR_BODY:%.*]] ]
-; CHECK-NEXT:    [[I:%.*]] = phi i32 [ 0, [[ENTRY]] ], [ [[INC:%.*]], [[FOR_BODY]] ]
+; CHECK-NEXT:    [[RES:%.*]] = phi i32 [ 0, [[ENTRY_SPLIT]] ], [ [[ADD:%.*]], [[TMP2:%.*]] ]
+; CHECK-NEXT:    [[I:%.*]] = phi i32 [ 0, [[ENTRY_SPLIT]] ], [ [[INC:%.*]], [[TMP2]] ]
 ; CHECK-NEXT:    [[CMP:%.*]] = icmp slt i32 [[I]], [[N]]
-; CHECK-NEXT:    br i1 [[CMP]], label [[FOR_BODY]], label [[FOR_COND_CLEANUP:%.*]]
+; CHECK-NEXT:    br i1 [[CMP]], label [[FOR_BODY:%.*]], label [[FOR_COND_CLEANUP_SPLIT:%.*]]
 ; CHECK:       for.body:
-; CHECK-NEXT:    [[COND1:%.*]] = select i1 [[COND]], i32 [[I]], i32 42
-; CHECK-NEXT:    [[ADD]] = add nuw nsw i32 [[COND1]], [[RES]]
+; CHECK-NEXT:    br label [[TMP2]]
+; CHECK:       2:
+; CHECK-NEXT:    [[ADD]] = add nuw nsw i32 42, [[RES]]
 ; CHECK-NEXT:    [[INC]] = add nuw nsw i32 [[I]], 1
 ; CHECK-NEXT:    br label [[FOR_COND]]
-; CHECK:       for.cond.cleanup:
+; CHECK:       for.cond.cleanup.split:
 ; CHECK-NEXT:    [[RES_LCSSA:%.*]] = phi i32 [ [[RES]], [[FOR_COND]] ]
-; CHECK-NEXT:    ret i32 [[RES_LCSSA]]
+; CHECK-NEXT:    br label [[FOR_COND_CLEANUP]]
+; CHECK:       for.cond.cleanup:
+; CHECK-NEXT:    [[DOTUS_PHI:%.*]] = phi i32 [ [[RES_LCSSA]], [[FOR_COND_CLEANUP_SPLIT]] ], [ [[RES_LCSSA_US]], [[FOR_COND_CLEANUP_SPLIT_US]] ]
+; CHECK-NEXT:    ret i32 [[DOTUS_PHI]]
 ;
 entry:
   br label %for.cond
@@ -164,21 +245,115 @@
 ; CHECK-LABEL: define i32 @chained_select
 ; CHECK-SAME: (i32 [[N:%.*]], i1 [[COND:%.*]], i1 [[COND2:%.*]]) {
 ; CHECK-NEXT:  entry:
+; CHECK-NEXT:    [[COND_FR1:%.*]] = freeze i1 [[COND]]
+; CHECK-NEXT:    br i1 [[COND_FR1]], label [[ENTRY_SPLIT_US:%.*]], label [[ENTRY_SPLIT:%.*]]
+; CHECK:       entry.split.us:
+; CHECK-NEXT:    [[COND2_FR17:%.*]] = freeze i1 [[COND2]]
+; CHECK-NEXT:    br i1 [[COND2_FR17]], label [[ENTRY_SPLIT_US_SPLIT_US:%.*]], label [[ENTRY_SPLIT_US_SPLIT:%.*]]
+; CHECK:       entry.split.us.split.us:
+; CHECK-NEXT:    br label [[FOR_COND_US_US:%.*]]
+; CHECK:       for.cond.us.us:
+; CHECK-NEXT:    [[RES_US_US:%.*]] = phi i32 [ 0, [[ENTRY_SPLIT_US_SPLIT_US]] ], [ [[ADD_US_US:%.*]], [[TMP3:%.*]] ]
+; CHECK-NEXT:    [[I_US_US:%.*]] = phi i32 [ 0, [[ENTRY_SPLIT_US_SPLIT_US]] ], [ [[INC_US_US:%.*]], [[TMP3]] ]
+; CHECK-NEXT:    [[CMP_US_US:%.*]] = icmp slt i32 [[I_US_US]], [[N]]
+; CHECK-NEXT:    br i1 [[CMP_US_US]], label [[FOR_BODY_US_US:%.*]], label [[FOR_COND_CLEANUP_SPLIT_US_SPLIT_US:%.*]]
+; CHECK:       for.body.us.us:
+; CHECK-NEXT:    [[COND_FR_US_US:%.*]] = freeze i1 true
+; CHECK-NEXT:    br label [[TMP0:%.*]]
+; CHECK:       0:
+; CHECK-NEXT:    br label [[TMP1:%.*]]
+; CHECK:       1:
+; CHECK-NEXT:    [[UNSWITCHED_SELECT_US_US:%.*]] = phi i32 [ [[I_US_US]], [[TMP0]] ]
+; CHECK-NEXT:    [[COND2_FR14_US:%.*]] = freeze i1 true
+; CHECK-NEXT:    br label [[TMP2:%.*]]
+; CHECK:       2:
+; CHECK-NEXT:    br label [[TMP3]]
+; CHECK:       3:
+; CHECK-NEXT:    [[UNSWITCHED_SELECT_US15:%.*]] = phi i32 [ [[UNSWITCHED_SELECT_US_US]], [[TMP2]] ]
+; CHECK-NEXT:    [[ADD_US_US]] = add nuw nsw i32 [[UNSWITCHED_SELECT_US15]], [[RES_US_US]]
+; CHECK-NEXT:    [[INC_US_US]] = add nuw nsw i32 [[I_US_US]], 1
+; CHECK-NEXT:    br label [[FOR_COND_US_US]]
+; CHECK:       for.cond.cleanup.split.us.split.us:
+; CHECK-NEXT:    [[RES_LCSSA_US_US:%.*]] = phi i32 [ [[RES_US_US]], [[FOR_COND_US_US]] ]
+; CHECK-NEXT:    br label [[FOR_COND_CLEANUP_SPLIT_US:%.*]]
+; CHECK:       entry.split.us.split:
+; CHECK-NEXT:    br label [[FOR_COND_US:%.*]]
+; CHECK:       for.cond.us:
+; CHECK-NEXT:    [[RES_US:%.*]] = phi i32 [ 0, [[ENTRY_SPLIT_US_SPLIT]] ], [ [[ADD_US:%.*]], [[TMP6:%.*]] ]
+; CHECK-NEXT:    [[I_US:%.*]] = phi i32 [ 0, [[ENTRY_SPLIT_US_SPLIT]] ], [ [[INC_US:%.*]], [[TMP6]] ]
+; CHECK-NEXT:    [[CMP_US:%.*]] = icmp slt i32 [[I_US]], [[N]]
+; CHECK-NEXT:    br i1 [[CMP_US]], label [[FOR_BODY_US:%.*]], label [[FOR_COND_CLEANUP_SPLIT_US_SPLIT:%.*]]
+; CHECK:       for.body.us:
+; CHECK-NEXT:    [[COND_FR_US:%.*]] = freeze i1 true
+; CHECK-NEXT:    br label [[TMP4:%.*]]
+; CHECK:       4:
+; CHECK-NEXT:    br label [[TMP5:%.*]]
+; CHECK:       5:
+; CHECK-NEXT:    [[UNSWITCHED_SELECT_US:%.*]] = phi i32 [ [[I_US]], [[TMP4]] ]
+; CHECK-NEXT:    [[COND2_FR14:%.*]] = freeze i1 false
+; CHECK-NEXT:    br label [[TMP6]]
+; CHECK:       6:
+; CHECK-NEXT:    [[ADD_US]] = add nuw nsw i32 24, [[RES_US]]
+; CHECK-NEXT:    [[INC_US]] = add nuw nsw i32 [[I_US]], 1
+; CHECK-NEXT:    br label [[FOR_COND_US]]
+; CHECK:       for.cond.cleanup.split.us.split:
+; CHECK-NEXT:    [[RES_LCSSA_US:%.*]] = phi i32 [ [[RES_US]], [[FOR_COND_US]] ]
+; CHECK-NEXT:    br label [[FOR_COND_CLEANUP_SPLIT_US]]
+; CHECK:       for.cond.cleanup.split.us:
+; CHECK-NEXT:    [[DOTUS_PHI16:%.*]] = phi i32 [ [[RES_LCSSA_US]], [[FOR_COND_CLEANUP_SPLIT_US_SPLIT]] ], [ [[RES_LCSSA_US_US]], [[FOR_COND_CLEANUP_SPLIT_US_SPLIT_US]] ]
+; CHECK-NEXT:    br label [[FOR_COND_CLEANUP:%.*]]
+; CHECK:       entry.split:
+; CHECK-NEXT:    [[COND2_FR13:%.*]] = freeze i1 [[COND2]]
+; CHECK-NEXT:    br i1 [[COND2_FR13]], label [[ENTRY_SPLIT_SPLIT_US:%.*]], label [[ENTRY_SPLIT_SPLIT:%.*]]
+; CHECK:       entry.split.split.us:
+; CHECK-NEXT:    br label [[FOR_COND_US2:%.*]]
+; CHECK:       for.cond.us2:
+; CHECK-NEXT:    [[RES_US3:%.*]] = phi i32 [ 0, [[ENTRY_SPLIT_SPLIT_US]] ], [ [[ADD_US9:%.*]], [[TMP9:%.*]] ]
+; CHECK-NEXT:    [[I_US4:%.*]] = phi i32 [ 0, [[ENTRY_SPLIT_SPLIT_US]] ], [ [[INC_US10:%.*]], [[TMP9]] ]
+; CHECK-NEXT:    [[CMP_US5:%.*]] = icmp slt i32 [[I_US4]], [[N]]
+; CHECK-NEXT:    br i1 [[CMP_US5]], label [[FOR_BODY_US6:%.*]], label [[FOR_COND_CLEANUP_SPLIT_SPLIT_US:%.*]]
+; CHECK:       for.body.us6:
+; CHECK-NEXT:    [[COND_FR_US7:%.*]] = freeze i1 false
+; CHECK-NEXT:    br label [[TMP7:%.*]]
+; CHECK:       7:
+; CHECK-NEXT:    [[COND2_FR_US:%.*]] = freeze i1 true
+; CHECK-NEXT:    br label [[TMP8:%.*]]
+; CHECK:       8:
+; CHECK-NEXT:    br label [[TMP9]]
+; CHECK:       9:
+; CHECK-NEXT:    [[UNSWITCHED_SELECT_US8:%.*]] = phi i32 [ 42, [[TMP8]] ]
+; CHECK-NEXT:    [[ADD_US9]] = add nuw nsw i32 [[UNSWITCHED_SELECT_US8]], [[RES_US3]]
+; CHECK-NEXT:    [[INC_US10]] = add nuw nsw i32 [[I_US4]], 1
+; CHECK-NEXT:    br label [[FOR_COND_US2]]
+; CHECK:       for.cond.cleanup.split.split.us:
+; CHECK-NEXT:    [[RES_LCSSA_US11:%.*]] = phi i32 [ [[RES_US3]], [[FOR_COND_US2]] ]
+; CHECK-NEXT:    br label [[FOR_COND_CLEANUP_SPLIT:%.*]]
+; CHECK:       entry.split.split:
 ; CHECK-NEXT:    br label [[FOR_COND:%.*]]
 ; CHECK:       for.cond:
-; CHECK-NEXT:    [[RES:%.*]] = phi i32 [ 0, [[ENTRY:%.*]] ], [ [[ADD:%.*]], [[FOR_BODY:%.*]] ]
-; CHECK-NEXT:    [[I:%.*]] = phi i32 [ 0, [[ENTRY]] ], [ [[INC:%.*]], [[FOR_BODY]] ]
+; CHECK-NEXT:    [[RES:%.*]] = phi i32 [ 0, [[ENTRY_SPLIT_SPLIT]] ], [ [[ADD:%.*]], [[TMP11:%.*]] ]
+; CHECK-NEXT:    [[I:%.*]] = phi i32 [ 0, [[ENTRY_SPLIT_SPLIT]] ], [ [[INC:%.*]], [[TMP11]] ]
 ; CHECK-NEXT:    [[CMP:%.*]] = icmp slt i32 [[I]], [[N]]
-; CHECK-NEXT:    br i1 [[CMP]], label [[FOR_BODY]], label [[FOR_COND_CLEANUP:%.*]]
+; CHECK-NEXT:    br i1 [[CMP]], label [[FOR_BODY:%.*]], label [[FOR_COND_CLEANUP_SPLIT_SPLIT:%.*]]
 ; CHECK:       for.body:
-; CHECK-NEXT:    [[SELECT1:%.*]] = select i1 [[COND]], i32 [[I]], i32 42
-; CHECK-NEXT:    [[SELECT2:%.*]] = select i1 [[COND2]], i32 [[SELECT1]], i32 24
-; CHECK-NEXT:    [[ADD]] = add nuw nsw i32 [[SELECT2]], [[RES]]
+; CHECK-NEXT:    [[COND_FR:%.*]] = freeze i1 false
+; CHECK-NEXT:    br label [[TMP10:%.*]]
+; CHECK:       10:
+; CHECK-NEXT:    [[COND2_FR:%.*]] = freeze i1 false
+; CHECK-NEXT:    br label [[TMP11]]
+; CHECK:       11:
+; CHECK-NEXT:    [[ADD]] = add nuw nsw i32 24, [[RES]]
 ; CHECK-NEXT:    [[INC]] = add nuw nsw i32 [[I]], 1
 ; CHECK-NEXT:    br label [[FOR_COND]]
-; CHECK:       for.cond.cleanup:
+; CHECK:       for.cond.cleanup.split.split:
 ; CHECK-NEXT:    [[RES_LCSSA:%.*]] = phi i32 [ [[RES]], [[FOR_COND]] ]
-; CHECK-NEXT:    ret i32 [[RES_LCSSA]]
+; CHECK-NEXT:    br label [[FOR_COND_CLEANUP_SPLIT]]
+; CHECK:       for.cond.cleanup.split:
+; CHECK-NEXT:    [[DOTUS_PHI12:%.*]] = phi i32 [ [[RES_LCSSA]], [[FOR_COND_CLEANUP_SPLIT_SPLIT]] ], [ [[RES_LCSSA_US11]], [[FOR_COND_CLEANUP_SPLIT_SPLIT_US]] ]
+; CHECK-NEXT:    br label [[FOR_COND_CLEANUP]]
+; CHECK:       for.cond.cleanup:
+; CHECK-NEXT:    [[DOTUS_PHI:%.*]] = phi i32 [ [[DOTUS_PHI12]], [[FOR_COND_CLEANUP_SPLIT]] ], [ [[DOTUS_PHI16]], [[FOR_COND_CLEANUP_SPLIT_US]] ]
+; CHECK-NEXT:    ret i32 [[DOTUS_PHI]]
 ;
 entry:
   br label %for.cond
@@ -204,27 +379,62 @@
 ; CHECK-LABEL: define i32 @select_in_if
 ; CHECK-SAME: (i32 [[N:%.*]], i1 [[COND:%.*]]) {
 ; CHECK-NEXT:  entry:
+; CHECK-NEXT:    [[COND_FR1:%.*]] = freeze i1 [[COND]]
+; CHECK-NEXT:    br i1 [[COND_FR1]], label [[ENTRY_SPLIT_US:%.*]], label [[ENTRY_SPLIT:%.*]]
+; CHECK:       entry.split.us:
+; CHECK-NEXT:    br label [[FOR_COND_US:%.*]]
+; CHECK:       for.cond.us:
+; CHECK-NEXT:    [[RES_US:%.*]] = phi i32 [ 0, [[ENTRY_SPLIT_US]] ], [ [[ADD_US:%.*]], [[FOR_BODY_END_US:%.*]] ]
+; CHECK-NEXT:    [[I_US:%.*]] = phi i32 [ 0, [[ENTRY_SPLIT_US]] ], [ [[INC_US:%.*]], [[FOR_BODY_END_US]] ]
+; CHECK-NEXT:    [[CMP_US:%.*]] = icmp slt i32 [[I_US]], [[N]]
+; CHECK-NEXT:    br i1 [[CMP_US]], label [[FOR_BODY_US:%.*]], label [[FOR_COND_CLEANUP_SPLIT_US:%.*]]
+; CHECK:       for.body.us:
+; CHECK-NEXT:    [[UREM_US:%.*]] = urem i32 [[I_US]], 2
+; CHECK-NEXT:    [[IF_COND_US:%.*]] = icmp eq i32 [[UREM_US]], 0
+; CHECK-NEXT:    br i1 [[IF_COND_US]], label [[FOR_BODY_IF_US:%.*]], label [[FOR_BODY_END_US]]
+; CHECK:       for.body.if.us:
+; CHECK-NEXT:    [[COND_FR_US:%.*]] = freeze i1 true
+; CHECK-NEXT:    br label [[TMP0:%.*]]
+; CHECK:       for.body.end.us:
+; CHECK-NEXT:    [[P_US:%.*]] = phi i32 [ [[UNSWITCHED_SELECT_US:%.*]], [[TMP1:%.*]] ], [ 24, [[FOR_BODY_US]] ]
+; CHECK-NEXT:    [[ADD_US]] = add nuw nsw i32 [[P_US]], [[RES_US]]
+; CHECK-NEXT:    [[INC_US]] = add nuw nsw i32 [[I_US]], 1
+; CHECK-NEXT:    br label [[FOR_COND_US]]
+; CHECK:       0:
+; CHECK-NEXT:    br label [[TMP1]]
+; CHECK:       1:
+; CHECK-NEXT:    [[UNSWITCHED_SELECT_US]] = phi i32 [ [[I_US]], [[TMP0]] ]
+; CHECK-NEXT:    br label [[FOR_BODY_END_US]]
+; CHECK:       for.cond.cleanup.split.us:
+; CHECK-NEXT:    [[RES_LCSSA_US:%.*]] = phi i32 [ [[RES_US]], [[FOR_COND_US]] ]
+; CHECK-NEXT:    br label [[FOR_COND_CLEANUP:%.*]]
+; CHECK:       entry.split:
 ; CHECK-NEXT:    br label [[FOR_COND:%.*]]
 ; CHECK:       for.cond:
-; CHECK-NEXT:    [[RES:%.*]] = phi i32 [ 0, [[ENTRY:%.*]] ], [ [[ADD:%.*]], [[FOR_BODY_END:%.*]] ]
-; CHECK-NEXT:    [[I:%.*]] = phi i32 [ 0, [[ENTRY]] ], [ [[INC:%.*]], [[FOR_BODY_END]] ]
+; CHECK-NEXT:    [[RES:%.*]] = phi i32 [ 0, [[ENTRY_SPLIT]] ], [ [[ADD:%.*]], [[FOR_BODY_END:%.*]] ]
+; CHECK-NEXT:    [[I:%.*]] = phi i32 [ 0, [[ENTRY_SPLIT]] ], [ [[INC:%.*]], [[FOR_BODY_END]] ]
 ; CHECK-NEXT:    [[CMP:%.*]] = icmp slt i32 [[I]], [[N]]
-; CHECK-NEXT:    br i1 [[CMP]], label [[FOR_BODY:%.*]], label [[FOR_COND_CLEANUP:%.*]]
+; CHECK-NEXT:    br i1 [[CMP]], label [[FOR_BODY:%.*]], label [[FOR_COND_CLEANUP_SPLIT:%.*]]
 ; CHECK:       for.body:
 ; CHECK-NEXT:    [[UREM:%.*]] = urem i32 [[I]], 2
 ; CHECK-NEXT:    [[IF_COND:%.*]] = icmp eq i32 [[UREM]], 0
 ; CHECK-NEXT:    br i1 [[IF_COND]], label [[FOR_BODY_IF:%.*]], label [[FOR_BODY_END]]
 ; CHECK:       for.body.if:
-; CHECK-NEXT:    [[COND1:%.*]] = select i1 [[COND]], i32 [[I]], i32 42
+; CHECK-NEXT:    [[COND_FR:%.*]] = freeze i1 false
+; CHECK-NEXT:    br label [[TMP2:%.*]]
+; CHECK:       2:
 ; CHECK-NEXT:    br label [[FOR_BODY_END]]
 ; CHECK:       for.body.end:
-; CHECK-NEXT:    [[P:%.*]] = phi i32 [ [[COND1]], [[FOR_BODY_IF]] ], [ 24, [[FOR_BODY]] ]
+; CHECK-NEXT:    [[P:%.*]] = phi i32 [ 42, [[TMP2]] ], [ 24, [[FOR_BODY]] ]
 ; CHECK-NEXT:    [[ADD]] = add nuw nsw i32 [[P]], [[RES]]
 ; CHECK-NEXT:    [[INC]] = add nuw nsw i32 [[I]], 1
 ; CHECK-NEXT:    br label [[FOR_COND]]
-; CHECK:       for.cond.cleanup:
+; CHECK:       for.cond.cleanup.split:
 ; CHECK-NEXT:    [[RES_LCSSA:%.*]] = phi i32 [ [[RES]], [[FOR_COND]] ]
-; CHECK-NEXT:    ret i32 [[RES_LCSSA]]
+; CHECK-NEXT:    br label [[FOR_COND_CLEANUP]]
+; CHECK:       for.cond.cleanup:
+; CHECK-NEXT:    [[DOTUS_PHI:%.*]] = phi i32 [ [[RES_LCSSA]], [[FOR_COND_CLEANUP_SPLIT]] ], [ [[RES_LCSSA_US]], [[FOR_COND_CLEANUP_SPLIT_US]] ]
+; CHECK-NEXT:    ret i32 [[DOTUS_PHI]]
 ;
 entry:
   br label %for.cond
@@ -258,30 +468,68 @@
 ; CHECK-LABEL: define i32 @select_in_if_else
 ; CHECK-SAME: (i32 [[N:%.*]], i1 [[COND:%.*]]) {
 ; CHECK-NEXT:  entry:
+; CHECK-NEXT:    [[COND_FR1:%.*]] = freeze i1 [[COND]]
+; CHECK-NEXT:    br i1 [[COND_FR1]], label [[ENTRY_SPLIT_US:%.*]], label [[ENTRY_SPLIT:%.*]]
+; CHECK:       entry.split.us:
+; CHECK-NEXT:    br label [[FOR_COND_US:%.*]]
+; CHECK:       for.cond.us:
+; CHECK-NEXT:    [[RES_US:%.*]] = phi i32 [ 0, [[ENTRY_SPLIT_US]] ], [ [[ADD_US:%.*]], [[FOR_BODY_END_US:%.*]] ]
+; CHECK-NEXT:    [[I_US:%.*]] = phi i32 [ 0, [[ENTRY_SPLIT_US]] ], [ [[INC_US:%.*]], [[FOR_BODY_END_US]] ]
+; CHECK-NEXT:    [[CMP_US:%.*]] = icmp slt i32 [[I_US]], [[N]]
+; CHECK-NEXT:    br i1 [[CMP_US]], label [[FOR_BODY_US:%.*]], label [[FOR_COND_CLEANUP_SPLIT_US:%.*]]
+; CHECK:       for.body.us:
+; CHECK-NEXT:    [[UREM_US:%.*]] = urem i32 [[I_US]], 2
+; CHECK-NEXT:    [[IF_COND_US:%.*]] = icmp eq i32 [[UREM_US]], 0
+; CHECK-NEXT:    br i1 [[IF_COND_US]], label [[FOR_BODY_IF_US:%.*]], label [[FOR_BODY_ELSE_US:%.*]]
+; CHECK:       for.body.else.us:
+; CHECK-NEXT:    [[COND_FR_US:%.*]] = freeze i1 true
+; CHECK-NEXT:    br label [[TMP0:%.*]]
+; CHECK:       for.body.if.us:
+; CHECK-NEXT:    [[COND1A_US:%.*]] = select i1 true, i32 [[I_US]], i32 42
+; CHECK-NEXT:    br label [[FOR_BODY_END_US]]
+; CHECK:       for.body.end.us:
+; CHECK-NEXT:    [[P_US:%.*]] = phi i32 [ [[COND1A_US]], [[FOR_BODY_IF_US]] ], [ [[UNSWITCHED_SELECT_US:%.*]], [[TMP1:%.*]] ]
+; CHECK-NEXT:    [[ADD_US]] = add nuw nsw i32 [[P_US]], [[RES_US]]
+; CHECK-NEXT:    [[INC_US]] = add nuw nsw i32 [[I_US]], 1
+; CHECK-NEXT:    br label [[FOR_COND_US]]
+; CHECK:       0:
+; CHECK-NEXT:    br label [[TMP1]]
+; CHECK:       1:
+; CHECK-NEXT:    [[UNSWITCHED_SELECT_US]] = phi i32 [ 24, [[TMP0]] ]
+; CHECK-NEXT:    br label [[FOR_BODY_END_US]]
+; CHECK:       for.cond.cleanup.split.us:
+; CHECK-NEXT:    [[RES_LCSSA_US:%.*]] = phi i32 [ [[RES_US]], [[FOR_COND_US]] ]
+; CHECK-NEXT:    br label [[FOR_COND_CLEANUP:%.*]]
+; CHECK:       entry.split:
 ; CHECK-NEXT:    br label [[FOR_COND:%.*]]
 ; CHECK:       for.cond:
-; CHECK-NEXT:    [[RES:%.*]] = phi i32 [ 0, [[ENTRY:%.*]] ], [ [[ADD:%.*]], [[FOR_BODY_END:%.*]] ]
-; CHECK-NEXT:    [[I:%.*]] = phi i32 [ 0, [[ENTRY]] ], [ [[INC:%.*]], [[FOR_BODY_END]] ]
+; CHECK-NEXT:    [[RES:%.*]] = phi i32 [ 0, [[ENTRY_SPLIT]] ], [ [[ADD:%.*]], [[FOR_BODY_END:%.*]] ]
+; CHECK-NEXT:    [[I:%.*]] = phi i32 [ 0, [[ENTRY_SPLIT]] ], [ [[INC:%.*]], [[FOR_BODY_END]] ]
 ; CHECK-NEXT:    [[CMP:%.*]] = icmp slt i32 [[I]], [[N]]
-; CHECK-NEXT:    br i1 [[CMP]], label [[FOR_BODY:%.*]], label [[FOR_COND_CLEANUP:%.*]]
+; CHECK-NEXT:    br i1 [[CMP]], label [[FOR_BODY:%.*]], label [[FOR_COND_CLEANUP_SPLIT:%.*]]
 ; CHECK:       for.body:
 ; CHECK-NEXT:    [[UREM:%.*]] = urem i32 [[I]], 2
 ; CHECK-NEXT:    [[IF_COND:%.*]] = icmp eq i32 [[UREM]], 0
 ; CHECK-NEXT:    br i1 [[IF_COND]], label [[FOR_BODY_IF:%.*]], label [[FOR_BODY_ELSE:%.*]]
 ; CHECK:       for.body.if:
-; CHECK-NEXT:    [[COND1A:%.*]] = select i1 [[COND]], i32 [[I]], i32 42
+; CHECK-NEXT:    [[COND1A:%.*]] = select i1 false, i32 [[I]], i32 42
 ; CHECK-NEXT:    br label [[FOR_BODY_END]]
 ; CHECK:       for.body.else:
-; CHECK-NEXT:    [[COND1B:%.*]] = select i1 [[COND]], i32 24, i32 [[I]]
+; CHECK-NEXT:    [[COND_FR:%.*]] = freeze i1 false
+; CHECK-NEXT:    br label [[TMP2:%.*]]
+; CHECK:       2:
 ; CHECK-NEXT:    br label [[FOR_BODY_END]]
 ; CHECK:       for.body.end:
-; CHECK-NEXT:    [[P:%.*]] = phi i32 [ [[COND1A]], [[FOR_BODY_IF]] ], [ [[COND1B]], [[FOR_BODY_ELSE]] ]
+; CHECK-NEXT:    [[P:%.*]] = phi i32 [ [[COND1A]], [[FOR_BODY_IF]] ], [ [[I]], [[TMP2]] ]
 ; CHECK-NEXT:    [[ADD]] = add nuw nsw i32 [[P]], [[RES]]
 ; CHECK-NEXT:    [[INC]] = add nuw nsw i32 [[I]], 1
 ; CHECK-NEXT:    br label [[FOR_COND]]
-; CHECK:       for.cond.cleanup:
+; CHECK:       for.cond.cleanup.split:
 ; CHECK-NEXT:    [[RES_LCSSA:%.*]] = phi i32 [ [[RES]], [[FOR_COND]] ]
-; CHECK-NEXT:    ret i32 [[RES_LCSSA]]
+; CHECK-NEXT:    br label [[FOR_COND_CLEANUP]]
+; CHECK:       for.cond.cleanup:
+; CHECK-NEXT:    [[DOTUS_PHI:%.*]] = phi i32 [ [[RES_LCSSA]], [[FOR_COND_CLEANUP_SPLIT]] ], [ [[RES_LCSSA_US]], [[FOR_COND_CLEANUP_SPLIT_US]] ]
+; CHECK-NEXT:    ret i32 [[DOTUS_PHI]]
 ;
 entry:
   br label %for.cond
@@ -324,21 +572,56 @@
 ; CHECK-NEXT:    [[OR_COND:%.*]] = or i1 [[CMP17_NOT]], [[CMP215_NOT]]
 ; CHECK-NEXT:    br i1 [[OR_COND]], label [[FOR_COND_CLEANUP:%.*]], label [[FOR_COND1_PREHEADER_US_PREHEADER:%.*]]
 ; CHECK:       for.cond1.preheader.us.preheader:
+; CHECK-NEXT:    br i1 [[COND]], label [[FOR_COND1_PREHEADER_US_PREHEADER_SPLIT_US:%.*]], label [[FOR_COND1_PREHEADER_US_PREHEADER_SPLIT:%.*]]
+; CHECK:       for.cond1.preheader.us.preheader.split.us:
+; CHECK-NEXT:    br label [[FOR_COND1_PREHEADER_US_US:%.*]]
+; CHECK:       for.cond1.preheader.us.us:
+; CHECK-NEXT:    [[I_018_US_US:%.*]] = phi i32 [ [[INC7_US_US:%.*]], [[FOR_COND1_FOR_COND_CLEANUP3_CRIT_EDGE_US_US:%.*]] ], [ 0, [[FOR_COND1_PREHEADER_US_PREHEADER_SPLIT_US]] ]
+; CHECK-NEXT:    br label [[FOR_COND1_PREHEADER_US_SPLIT_US_US:%.*]]
+; CHECK:       for.cond1.for.cond.cleanup3_crit_edge.us.us:
+; CHECK-NEXT:    [[INC7_US_US]] = add nuw i32 [[I_018_US_US]], 1
+; CHECK-NEXT:    [[EXITCOND21_NOT_US:%.*]] = icmp eq i32 [[INC7_US_US]], [[N]]
+; CHECK-NEXT:    br i1 [[EXITCOND21_NOT_US]], label [[FOR_COND_CLEANUP_LOOPEXIT_SPLIT_US:%.*]], label [[FOR_COND1_PREHEADER_US_US]]
+; CHECK:       for.cond1.preheader.us.split.us.us:
+; CHECK-NEXT:    br label [[FOR_BODY4_US_US_US:%.*]]
+; CHECK:       for.body4.us.us.us:
+; CHECK-NEXT:    [[J_016_US_US_US:%.*]] = phi i32 [ 0, [[FOR_COND1_PREHEADER_US_SPLIT_US_US]] ], [ [[INC_US_US_US:%.*]], [[TMP1:%.*]] ]
+; CHECK-NEXT:    br label [[TMP0:%.*]]
+; CHECK:       0:
+; CHECK-NEXT:    br label [[TMP1]]
+; CHECK:       1:
+; CHECK-NEXT:    [[UNSWITCHED_SELECT_US_US:%.*]] = phi i32 [ [[I_018_US_US]], [[TMP0]] ]
+; CHECK-NEXT:    tail call void @bar(i32 noundef [[UNSWITCHED_SELECT_US_US]])
+; CHECK-NEXT:    [[INC_US_US_US]] = add nuw i32 [[J_016_US_US_US]], 1
+; CHECK-NEXT:    [[EXITCOND_NOT_US_US:%.*]] = icmp eq i32 [[INC_US_US_US]], [[M]]
+; CHECK-NEXT:    br i1 [[EXITCOND_NOT_US_US]], label [[FOR_COND1_FOR_COND_CLEANUP3_CRIT_EDGE_US_SPLIT_US_US:%.*]], label [[FOR_BODY4_US_US_US]]
+; CHECK:       for.cond1.for.cond.cleanup3_crit_edge.us.split.us.us:
+; CHECK-NEXT:    br label [[FOR_COND1_FOR_COND_CLEANUP3_CRIT_EDGE_US_US]]
+; CHECK:       for.cond.cleanup.loopexit.split.us:
+; CHECK-NEXT:    br label [[FOR_COND_CLEANUP_LOOPEXIT:%.*]]
+; CHECK:       for.cond1.preheader.us.preheader.split:
 ; CHECK-NEXT:    br label [[FOR_COND1_PREHEADER_US:%.*]]
 ; CHECK:       for.cond1.preheader.us:
-; CHECK-NEXT:    [[I_018_US:%.*]] = phi i32 [ [[INC7_US:%.*]], [[FOR_COND1_FOR_COND_CLEANUP3_CRIT_EDGE_US:%.*]] ], [ 0, [[FOR_COND1_PREHEADER_US_PREHEADER]] ]
+; CHECK-NEXT:    [[I_018_US:%.*]] = phi i32 [ [[INC7_US:%.*]], [[FOR_COND1_FOR_COND_CLEANUP3_CRIT_EDGE_US:%.*]] ], [ 0, [[FOR_COND1_PREHEADER_US_PREHEADER_SPLIT]] ]
+; CHECK-NEXT:    br label [[FOR_COND1_PREHEADER_US_SPLIT:%.*]]
+; CHECK:       for.cond1.preheader.us.split:
 ; CHECK-NEXT:    br label [[FOR_BODY4_US:%.*]]
 ; CHECK:       for.body4.us:
-; CHECK-NEXT:    [[J_016_US:%.*]] = phi i32 [ 0, [[FOR_COND1_PREHEADER_US]] ], [ [[INC_US:%.*]], [[FOR_BODY4_US]] ]
-; CHECK-NEXT:    [[COND5_US:%.*]] = select i1 [[COND]], i32 [[I_018_US]], i32 [[J_016_US]]
-; CHECK-NEXT:    tail call void @bar(i32 noundef [[COND5_US]])
+; CHECK-NEXT:    [[J_016_US:%.*]] = phi i32 [ 0, [[FOR_COND1_PREHEADER_US_SPLIT]] ], [ [[INC_US:%.*]], [[TMP2:%.*]] ]
+; CHECK-NEXT:    br label [[TMP2]]
+; CHECK:       2:
+; CHECK-NEXT:    tail call void @bar(i32 noundef [[J_016_US]])
 ; CHECK-NEXT:    [[INC_US]] = add nuw i32 [[J_016_US]], 1
 ; CHECK-NEXT:    [[EXITCOND_NOT:%.*]] = icmp eq i32 [[INC_US]], [[M]]
-; CHECK-NEXT:    br i1 [[EXITCOND_NOT]], label [[FOR_COND1_FOR_COND_CLEANUP3_CRIT_EDGE_US]], label [[FOR_BODY4_US]]
+; CHECK-NEXT:    br i1 [[EXITCOND_NOT]], label [[FOR_COND1_FOR_COND_CLEANUP3_CRIT_EDGE_US_SPLIT:%.*]], label [[FOR_BODY4_US]]
+; CHECK:       for.cond1.for.cond.cleanup3_crit_edge.us.split:
+; CHECK-NEXT:    br label [[FOR_COND1_FOR_COND_CLEANUP3_CRIT_EDGE_US]]
 ; CHECK:       for.cond1.for.cond.cleanup3_crit_edge.us:
 ; CHECK-NEXT:    [[INC7_US]] = add nuw i32 [[I_018_US]], 1
 ; CHECK-NEXT:    [[EXITCOND21_NOT:%.*]] = icmp eq i32 [[INC7_US]], [[N]]
-; CHECK-NEXT:    br i1 [[EXITCOND21_NOT]], label [[FOR_COND_CLEANUP_LOOPEXIT:%.*]], label [[FOR_COND1_PREHEADER_US]]
+; CHECK-NEXT:    br i1 [[EXITCOND21_NOT]], label [[FOR_COND_CLEANUP_LOOPEXIT_SPLIT:%.*]], label [[FOR_COND1_PREHEADER_US]]
+; CHECK:       for.cond.cleanup.loopexit.split:
+; CHECK-NEXT:    br label [[FOR_COND_CLEANUP_LOOPEXIT]]
 ; CHECK:       for.cond.cleanup.loopexit:
 ; CHECK-NEXT:    br label [[FOR_COND_CLEANUP]]
 ; CHECK:       for.cond.cleanup:
@@ -385,14 +668,36 @@
 ; CHECK-NEXT:    [[I_021_US:%.*]] = phi i32 [ [[INC9_US:%.*]], [[FOR_COND1_FOR_COND_CLEANUP3_CRIT_EDGE_US:%.*]] ], [ 0, [[FOR_COND1_PREHEADER_US_PREHEADER]] ]
 ; CHECK-NEXT:    [[REM_US:%.*]] = and i32 [[I_021_US]], 1
 ; CHECK-NEXT:    [[CMP5_US:%.*]] = icmp eq i32 [[REM_US]], 0
+; CHECK-NEXT:    br i1 [[CMP5_US]], label [[FOR_COND1_PREHEADER_US_SPLIT_US:%.*]], label [[FOR_COND1_PREHEADER_US_SPLIT:%.*]]
+; CHECK:       for.cond1.preheader.us.split.us:
+; CHECK-NEXT:    br label [[FOR_BODY4_US_US:%.*]]
+; CHECK:       for.body4.us.us:
+; CHECK-NEXT:    [[J_019_US_US:%.*]] = phi i32 [ 0, [[FOR_COND1_PREHEADER_US_SPLIT_US]] ], [ [[INC_US_US:%.*]], [[TMP1:%.*]] ]
+; CHECK-NEXT:    [[CMP5_US_FR_US:%.*]] = freeze i1 true
+; CHECK-NEXT:    br label [[TMP0:%.*]]
+; CHECK:       0:
+; CHECK-NEXT:    br label [[TMP1]]
+; CHECK:       1:
+; CHECK-NEXT:    [[UNSWITCHED_SELECT_US:%.*]] = phi i32 [ [[I_021_US]], [[TMP0]] ]
+; CHECK-NEXT:    tail call void @bar(i32 noundef [[UNSWITCHED_SELECT_US]])
+; CHECK-NEXT:    [[INC_US_US]] = add nuw i32 [[J_019_US_US]], 1
+; CHECK-NEXT:    [[EXITCOND_NOT_US:%.*]] = icmp eq i32 [[INC_US_US]], [[M]]
+; CHECK-NEXT:    br i1 [[EXITCOND_NOT_US]], label [[FOR_COND1_FOR_COND_CLEANUP3_CRIT_EDGE_US_SPLIT_US:%.*]], label [[FOR_BODY4_US_US]]
+; CHECK:       for.cond1.for.cond.cleanup3_crit_edge.us.split.us:
+; CHECK-NEXT:    br label [[FOR_COND1_FOR_COND_CLEANUP3_CRIT_EDGE_US]]
+; CHECK:       for.cond1.preheader.us.split:
 ; CHECK-NEXT:    br label [[FOR_BODY4_US:%.*]]
 ; CHECK:       for.body4.us:
-; CHECK-NEXT:    [[J_019_US:%.*]] = phi i32 [ 0, [[FOR_COND1_PREHEADER_US]] ], [ [[INC_US:%.*]], [[FOR_BODY4_US]] ]
-; CHECK-NEXT:    [[COND7_US:%.*]] = select i1 [[CMP5_US]], i32 [[I_021_US]], i32 [[J_019_US]]
-; CHECK-NEXT:    tail call void @bar(i32 noundef [[COND7_US]])
+; CHECK-NEXT:    [[J_019_US:%.*]] = phi i32 [ 0, [[FOR_COND1_PREHEADER_US_SPLIT]] ], [ [[INC_US:%.*]], [[TMP2:%.*]] ]
+; CHECK-NEXT:    [[CMP5_US_FR:%.*]] = freeze i1 false
+; CHECK-NEXT:    br label [[TMP2]]
+; CHECK:       2:
+; CHECK-NEXT:    tail call void @bar(i32 noundef [[J_019_US]])
 ; CHECK-NEXT:    [[INC_US]] = add nuw i32 [[J_019_US]], 1
 ; CHECK-NEXT:    [[EXITCOND_NOT:%.*]] = icmp eq i32 [[INC_US]], [[M]]
-; CHECK-NEXT:    br i1 [[EXITCOND_NOT]], label [[FOR_COND1_FOR_COND_CLEANUP3_CRIT_EDGE_US]], label [[FOR_BODY4_US]]
+; CHECK-NEXT:    br i1 [[EXITCOND_NOT]], label [[FOR_COND1_FOR_COND_CLEANUP3_CRIT_EDGE_US_SPLIT:%.*]], label [[FOR_BODY4_US]]
+; CHECK:       for.cond1.for.cond.cleanup3_crit_edge.us.split:
+; CHECK-NEXT:    br label [[FOR_COND1_FOR_COND_CLEANUP3_CRIT_EDGE_US]]
 ; CHECK:       for.cond1.for.cond.cleanup3_crit_edge.us:
 ; CHECK-NEXT:    [[INC9_US]] = add nuw i32 [[I_021_US]], 1
 ; CHECK-NEXT:    [[EXITCOND24_NOT:%.*]] = icmp eq i32 [[INC9_US]], [[N]]
diff --git a/llvm/test/Transforms/SimpleLoopUnswitch/nontrivial-unswitch-trivial-select.ll b/llvm/test/Transforms/SimpleLoopUnswitch/nontrivial-unswitch-trivial-select.ll
--- a/llvm/test/Transforms/SimpleLoopUnswitch/nontrivial-unswitch-trivial-select.ll
+++ b/llvm/test/Transforms/SimpleLoopUnswitch/nontrivial-unswitch-trivial-select.ll
@@ -92,17 +92,31 @@
 ; CHECK:       entry.split.us:
 ; CHECK-NEXT:    br label [[LOOP_US:%.*]]
 ; CHECK:       loop.us:
-; CHECK-NEXT:    [[P_US:%.*]] = phi i32 [ 0, [[ENTRY_SPLIT_US]] ], [ 35, [[LOOP_US]] ]
-; CHECK-NEXT:    br label [[LOOP_US]]
+; CHECK-NEXT:    [[P_US:%.*]] = phi i32 [ 0, [[ENTRY_SPLIT_US]] ], [ 35, [[TMP1:%.*]] ]
+; CHECK-NEXT:    [[C_FR_US:%.*]] = freeze i1 true
+; CHECK-NEXT:    br label [[TMP0:%.*]]
+; CHECK:       0:
+; CHECK-NEXT:    br label [[TMP1]]
+; CHECK:       1:
+; CHECK-NEXT:    [[UNSWITCHED_SELECT_US:%.*]] = phi i1 [ true, [[TMP0]] ]
+; CHECK-NEXT:    br i1 [[UNSWITCHED_SELECT_US]], label [[LOOP_US]], label [[EXIT_SPLIT_US:%.*]]
+; CHECK:       exit.split.us:
+; CHECK-NEXT:    [[LCSSA_US:%.*]] = phi i32 [ [[P_US]], [[TMP1]] ]
+; CHECK-NEXT:    br label [[EXIT:%.*]]
 ; CHECK:       entry.split:
 ; CHECK-NEXT:    br label [[LOOP:%.*]]
 ; CHECK:       loop:
-; CHECK-NEXT:    [[P:%.*]] = phi i32 [ 0, [[ENTRY_SPLIT]] ]
-; CHECK-NEXT:    [[SPEC_SELECT:%.*]] = select i1 false, i1 true, i1 false
-; CHECK-NEXT:    br label [[EXIT:%.*]]
+; CHECK-NEXT:    [[P:%.*]] = phi i32 [ 0, [[ENTRY_SPLIT]] ], [ 35, [[TMP2:%.*]] ]
+; CHECK-NEXT:    [[C_FR:%.*]] = freeze i1 false
+; CHECK-NEXT:    br label [[TMP2]]
+; CHECK:       2:
+; CHECK-NEXT:    br i1 false, label [[LOOP]], label [[EXIT_SPLIT:%.*]]
+; CHECK:       exit.split:
+; CHECK-NEXT:    [[LCSSA:%.*]] = phi i32 [ [[P]], [[TMP2]] ]
+; CHECK-NEXT:    br label [[EXIT]]
 ; CHECK:       exit:
-; CHECK-NEXT:    [[LCSSA:%.*]] = phi i32 [ [[P]], [[LOOP]] ]
-; CHECK-NEXT:    ret i32 [[LCSSA]]
+; CHECK-NEXT:    [[DOTUS_PHI:%.*]] = phi i32 [ [[LCSSA]], [[EXIT_SPLIT]] ], [ [[LCSSA_US]], [[EXIT_SPLIT_US]] ]
+; CHECK-NEXT:    ret i32 [[DOTUS_PHI]]
 ;
 entry:
   %c = icmp ult i32 %x, 100