Index: lib/Transforms/Scalar/InductiveRangeCheckElimination.cpp
===================================================================
--- lib/Transforms/Scalar/InductiveRangeCheckElimination.cpp
+++ lib/Transforms/Scalar/InductiveRangeCheckElimination.cpp
@@ -199,7 +199,10 @@
 class InductiveRangeCheckElimination : public LoopPass {
 public:
   static char ID;
-  InductiveRangeCheckElimination() : LoopPass(ID) {
+  InductiveRangeCheckElimination(bool AllowPreLoopInsertion = true,
+                                 bool AllowPostLoopInsertion = true)
+      : LoopPass(ID), AllowPreLoopInsertion(AllowPreLoopInsertion),
+        AllowPostLoopInsertion(AllowPostLoopInsertion) {
     initializeInductiveRangeCheckEliminationPass(
         *PassRegistry::getPassRegistry());
   }
@@ -210,6 +213,13 @@
   }
 
   bool runOnLoop(Loop *L, LPPassManager &LPM) override;
+
+private:
+  // Whether or not this pass run allows inserting of pre- and postloop. In case
+  // if either of them is not allowed but required, the whole transform gets
+  // rejected.
+  bool AllowPreLoopInsertion;
+  bool AllowPostLoopInsertion;
 };
 
 char InductiveRangeCheckElimination::ID = 0;
@@ -644,14 +654,21 @@
   // for a definition)
   LoopStructure MainLoopStructure;
 
+  // Whether or not we are allowed to insert pre- and postloop constraining.
+  bool AllowPreLoopInsertion;
+  bool AllowPostLoopInsertion;
+
 public:
   LoopConstrainer(Loop &L, LoopInfo &LI, LPPassManager &LPM,
                   const LoopStructure &LS, ScalarEvolution &SE,
-                  DominatorTree &DT, InductiveRangeCheck::Range R)
+                  DominatorTree &DT, InductiveRangeCheck::Range R,
+                  bool AllowPreLoopInsertion, bool AllowPostLoopInsertion)
       : F(*L.getHeader()->getParent()), Ctx(L.getHeader()->getContext()),
         SE(SE), DT(DT), LPM(LPM), LI(LI), OriginalLoop(L),
         LatchTakenCount(nullptr), OriginalPreheader(nullptr),
-        MainLoopPreheader(nullptr), Range(R), MainLoopStructure(LS) {}
+        MainLoopPreheader(nullptr), Range(R), MainLoopStructure(LS),
+        AllowPreLoopInsertion(AllowPreLoopInsertion),
+        AllowPostLoopInsertion(AllowPostLoopInsertion) {}
 
   // Entry point for the algorithm.  Returns true on success.
   bool run();
@@ -1473,6 +1490,19 @@
   bool NeedsPostLoop =
       Increasing ? SR.HighLimit.hasValue() : SR.LowLimit.hasValue();
 
+  // Check if we have prohibited insertion of pre- and postloop explicitly.
+  if (NeedsPreLoop && !AllowPreLoopInsertion) {
+    DEBUG(dbgs() << "irce: could not insert a preloop because it was explicitly"
+                 << " prohibited\n");
+    return false;
+  }
+
+  if (NeedsPostLoop && !AllowPostLoopInsertion) {
+    DEBUG(dbgs() << "irce: could not insert a postloop because it was"
+                 << " explicitly prohibited\n");
+    return false;
+  }
+
   Value *ExitPreLoopAt = nullptr;
   Value *ExitMainLoopAt = nullptr;
   const SCEVConstant *MinusOneS =
@@ -1763,7 +1793,8 @@
 
   auto &DT = getAnalysis<DominatorTreeWrapperPass>().getDomTree();
   LoopConstrainer LC(*L, getAnalysis<LoopInfoWrapperPass>().getLoopInfo(), LPM,
-                     LS, SE, DT, SafeIterRange.getValue());
+                     LS, SE, DT, SafeIterRange.getValue(),
+                     AllowPreLoopInsertion, AllowPostLoopInsertion);
   bool Changed = LC.run();
 
   if (Changed) {