Index: llvm/include/llvm/Passes/StandardInstrumentations.h
===================================================================
--- llvm/include/llvm/Passes/StandardInstrumentations.h
+++ llvm/include/llvm/Passes/StandardInstrumentations.h
@@ -145,7 +145,7 @@
                     FunctionAnalysisManager::Invalidator &);
   };
 
-#ifndef NDEBUG
+#ifdef LLVM_ENABLE_ABI_BREAKING_CHECKS
   SmallVector<StringRef, 8> PassStack;
 #endif
 
Index: llvm/include/llvm/Support/GenericDomTreeConstruction.h
===================================================================
--- llvm/include/llvm/Support/GenericDomTreeConstruction.h
+++ llvm/include/llvm/Support/GenericDomTreeConstruction.h
@@ -643,7 +643,7 @@
         Bucket;
     SmallDenseSet<TreeNodePtr, 8> Visited;
     SmallVector<TreeNodePtr, 8> Affected;
-#ifndef NDEBUG
+#ifdef LLVM_ENABLE_ABI_BREAKING_CHECKS
     SmallVector<TreeNodePtr, 8> VisitedUnaffected;
 #endif
   };
@@ -852,7 +852,7 @@
       TN->setIDom(NCD);
     }
 
-#ifndef NDEBUG
+#ifdef LLVM_ENABLE_ABI_BREAKING_CHECKS
     for (const TreeNodePtr TN : II.VisitedUnaffected)
       assert(TN->getLevel() == TN->getIDom()->getLevel() + 1 &&
              "TN should have been updated by an affected ancestor");
@@ -918,7 +918,7 @@
     LLVM_DEBUG(dbgs() << "Deleting edge " << BlockNamePrinter(From) << " -> "
                       << BlockNamePrinter(To) << "\n");
 
-#ifndef NDEBUG
+#ifdef LLVM_ENABLE_ABI_BREAKING_CHECKS
     // Ensure that the edge was in fact deleted from the CFG before informing
     // the DomTree about it.
     // The check is O(N), so run it only in debug configuration.
Index: llvm/include/llvm/Transforms/Scalar/JumpThreading.h
===================================================================
--- llvm/include/llvm/Transforms/Scalar/JumpThreading.h
+++ llvm/include/llvm/Transforms/Scalar/JumpThreading.h
@@ -85,7 +85,7 @@
   std::unique_ptr<BranchProbabilityInfo> BPI;
   bool HasProfileData = false;
   bool HasGuards = false;
-#ifdef NDEBUG
+#ifndef LLVM_ENABLE_ABI_BREAKING_CHECKS
   SmallPtrSet<const BasicBlock *, 16> LoopHeaders;
 #else
   SmallSet<AssertingVH<const BasicBlock>, 16> LoopHeaders;
Index: llvm/include/llvm/Transforms/Scalar/LoopPassManager.h
===================================================================
--- llvm/include/llvm/Transforms/Scalar/LoopPassManager.h
+++ llvm/include/llvm/Transforms/Scalar/LoopPassManager.h
@@ -269,7 +269,7 @@
   }
 
   void setParentLoop(Loop *L) {
-#ifndef NDEBUG
+#ifdef LLVM_ENABLE_ABI_BREAKING_CHECKS
     ParentL = L;
 #endif
   }
@@ -308,7 +308,7 @@
   /// loops within them will be visited in postorder as usual for the loop pass
   /// manager.
   void addSiblingLoops(ArrayRef<Loop *> NewSibLoops) {
-#ifndef NDEBUG
+#if defined(LLVM_ENABLE_ABI_BREAKING_CHECKS) && !defined(NDEBUG)
     for (Loop *NewL : NewSibLoops)
       assert(NewL->getParentLoop() == ParentL &&
              "All of the new loops must be siblings of the current loop!");
@@ -349,7 +349,7 @@
   bool SkipCurrentLoop;
   const bool LoopNestMode;
 
-#ifndef NDEBUG
+#ifdef LLVM_ENABLE_ABI_BREAKING_CHECKS
   // In debug builds we also track the parent loop to implement asserts even in
   // the face of loop deletion.
   Loop *ParentL;
Index: llvm/include/llvm/Transforms/Utils/ScalarEvolutionExpander.h
===================================================================
--- llvm/include/llvm/Transforms/Utils/ScalarEvolutionExpander.h
+++ llvm/include/llvm/Transforms/Utils/ScalarEvolutionExpander.h
@@ -160,7 +160,7 @@
   /// consistent when instructions are moved.
   SmallVector<SCEVInsertPointGuard *, 8> InsertPointGuards;
 
-#ifndef NDEBUG
+#ifdef LLVM_ENABLE_ABI_BREAKING_CHECKS
   const char *DebugType;
 #endif
 
@@ -176,7 +176,7 @@
         Builder(se.getContext(), TargetFolder(DL),
                 IRBuilderCallbackInserter(
                     [this](Instruction *I) { rememberInstruction(I); })) {
-#ifndef NDEBUG
+#ifdef LLVM_ENABLE_ABI_BREAKING_CHECKS
     DebugType = "";
 #endif
   }
@@ -186,7 +186,7 @@
     assert(InsertPointGuards.empty());
   }
 
-#ifndef NDEBUG
+#ifdef LLVM_ENABLE_ABI_BREAKING_CHECKS
   void setDebugType(const char *s) { DebugType = s; }
 #endif
 
Index: llvm/lib/Passes/StandardInstrumentations.cpp
===================================================================
--- llvm/lib/Passes/StandardInstrumentations.cpp
+++ llvm/lib/Passes/StandardInstrumentations.cpp
@@ -1086,7 +1086,9 @@
 
   PIC.registerBeforeNonSkippedPassCallback(
       [this, &FAM](StringRef P, Any IR) {
+#ifdef LLVM_ENABLE_ABI_BREAKING_CHECKS
         assert(&PassStack.emplace_back(P));
+#endif
         (void)this;
         if (!any_isa<const Function *>(IR))
           return;
@@ -1098,16 +1100,20 @@
 
   PIC.registerAfterPassInvalidatedCallback(
       [this](StringRef P, const PreservedAnalyses &PassPA) {
+#ifdef LLVM_ENABLE_ABI_BREAKING_CHECKS
         assert(PassStack.pop_back_val() == P &&
                "Before and After callbacks must correspond");
+#endif
         (void)this;
       });
 
   PIC.registerAfterPassCallback([this, &FAM,
                                  checkCFG](StringRef P, Any IR,
                                            const PreservedAnalyses &PassPA) {
+#ifdef LLVM_ENABLE_ABI_BREAKING_CHECKS
     assert(PassStack.pop_back_val() == P &&
            "Before and After callbacks must correspond");
+#endif
     (void)this;
 
     if (!any_isa<const Function *>(IR))
Index: llvm/lib/Transforms/Utils/ScalarEvolutionExpander.cpp
===================================================================
--- llvm/lib/Transforms/Utils/ScalarEvolutionExpander.cpp
+++ llvm/lib/Transforms/Utils/ScalarEvolutionExpander.cpp
@@ -29,6 +29,12 @@
 #include "llvm/Support/raw_ostream.h"
 #include "llvm/Transforms/Utils/LoopUtils.h"
 
+#ifdef LLVM_ENABLE_ABI_BREAKING_CHECKS
+#define SCEV_DEBUG_WITH_TYPE(TYPE, X) DEBUG_WITH_TYPE(TYPE, X)
+#else
+#define SCEV_DEBUG_WITH_TYPE(TYPE, X)
+#endif
+
 using namespace llvm;
 
 cl::opt<unsigned> llvm::SCEVCheapExpansionBudget(
@@ -1225,7 +1231,7 @@
       // We should not look for a incomplete PHI. Getting SCEV for a incomplete
       // PHI has no meaning at all.
       if (!PN.isComplete()) {
-        DEBUG_WITH_TYPE(
+        SCEV_DEBUG_WITH_TYPE(
             DebugType, dbgs() << "One incomplete PHI is found: " << PN << "\n");
         continue;
       }
@@ -2086,8 +2092,9 @@
       Phi->replaceAllUsesWith(V);
       DeadInsts.emplace_back(Phi);
       ++NumElim;
-      DEBUG_WITH_TYPE(DebugType, dbgs()
-                      << "INDVARS: Eliminated constant iv: " << *Phi << '\n');
+      SCEV_DEBUG_WITH_TYPE(DebugType,
+                           dbgs() << "INDVARS: Eliminated congruent iv.inc: "
+                                  << *IsomorphicInc << '\n');
       continue;
     }
 
@@ -2144,7 +2151,7 @@
             TruncExpr == SE.getSCEV(IsomorphicInc) &&
             SE.LI.replacementPreservesLCSSAForm(IsomorphicInc, OrigInc) &&
             hoistIVInc(OrigInc, IsomorphicInc)) {
-          DEBUG_WITH_TYPE(DebugType,
+          SCEV_DEBUG_WITH_TYPE(DebugType,
                           dbgs() << "INDVARS: Eliminated congruent iv.inc: "
                                  << *IsomorphicInc << '\n');
           Value *NewInc = OrigInc;
@@ -2165,9 +2172,9 @@
         }
       }
     }
-    DEBUG_WITH_TYPE(DebugType, dbgs() << "INDVARS: Eliminated congruent iv: "
+    SCEV_DEBUG_WITH_TYPE(DebugType, dbgs() << "INDVARS: Eliminated congruent iv: "
                                       << *Phi << '\n');
-    DEBUG_WITH_TYPE(DebugType, dbgs() << "INDVARS: Original iv: "
+    SCEV_DEBUG_WITH_TYPE(DebugType, dbgs() << "INDVARS: Original iv: "
                                       << *OrigPhiRef << '\n');
     ++NumElim;
     Value *NewIV = OrigPhiRef;