Index: include/polly/ScopInfo.h
===================================================================
--- include/polly/ScopInfo.h
+++ include/polly/ScopInfo.h
@@ -1404,6 +1404,9 @@
   bool contains(Instruction *Inst) const {
     if (!Inst)
       return false;
+    if (isBlockStmt())
+      return std::find(Instructions.begin(), Instructions.end(), Inst) !=
+             Instructions.end();
     return represents(Inst->getParent());
   }
 
@@ -1748,6 +1751,9 @@
   /// vector comprises only of a single statement.
   DenseMap<BasicBlock *, std::vector<ScopStmt *>> StmtMap;
 
+  /// A map from instructions to SCoP statements.
+  DenseMap<Instruction *, ScopStmt *> InstStmtMap;
+
   /// A map from basic blocks to their domains.
   DenseMap<BasicBlock *, isl::set> DomainMap;
 
@@ -2707,7 +2713,7 @@
   /// Return the ScopStmt an instruction belongs to, or nullptr if it
   ///        does not belong to any statement in this Scop.
   ScopStmt *getStmtFor(Instruction *Inst) const {
-    return getStmtFor(Inst->getParent());
+    return InstStmtMap.lookup(Inst);
   }
 
   /// Return the number of statements in the SCoP.
Index: lib/Analysis/ScopInfo.cpp
===================================================================
--- lib/Analysis/ScopInfo.cpp
+++ lib/Analysis/ScopInfo.cpp
@@ -1289,7 +1289,6 @@
     MAL.emplace_front(Access);
   } else if (Access->isValueKind() && Access->isWrite()) {
     Instruction *AccessVal = cast<Instruction>(Access->getAccessValue());
-    assert(Parent.getStmtFor(AccessVal) == this);
     assert(!ValueWrites.lookup(AccessVal));
 
     ValueWrites[AccessVal] = Access;
@@ -3790,10 +3789,16 @@
 
 void Scop::removeFromStmtMap(ScopStmt &Stmt) {
   if (Stmt.isRegionStmt())
-    for (BasicBlock *BB : Stmt.getRegion()->blocks())
+    for (BasicBlock *BB : Stmt.getRegion()->blocks()) {
       StmtMap.erase(BB);
-  else
+      for (Instruction &Inst : *BB)
+        InstStmtMap.erase(&Inst);
+    }
+  else {
     StmtMap.erase(Stmt.getBasicBlock());
+    for (Instruction *Inst : Stmt.getInstructions())
+      InstStmtMap.erase(Inst);
+  }
 }
 
 void Scop::removeStmts(std::function<bool(ScopStmt &)> ShouldDelete) {
@@ -4123,11 +4128,11 @@
   auto &RIL = getRequiredInvariantLoads();
   for (LoadInst *LI : RIL) {
     assert(LI && contains(LI));
-    ScopStmt *Stmt = getStmtFor(LI);
-    if (Stmt && Stmt->getArrayAccessOrNULLFor(LI)) {
-      invalidate(INVARIANTLOAD, LI->getDebugLoc(), LI->getParent());
-      return;
-    }
+    for (ScopStmt &Stmt : Stmts)
+      if (Stmt.getArrayAccessOrNULLFor(LI)) {
+        invalidate(INVARIANTLOAD, LI->getDebugLoc(), LI->getParent());
+        return;
+      }
   }
 }
 
@@ -4859,14 +4864,25 @@
   Stmts.emplace_back(*this, *BB, SurroundingLoop, Instructions);
   auto *Stmt = &Stmts.back();
   StmtMap[BB].push_back(Stmt);
+  for (Instruction *Inst : Instructions) {
+    assert(!InstStmtMap.count(Inst) &&
+           "Unexpected statement corresponding to the instruction.");
+    InstStmtMap[Inst] = Stmt;
+  }
 }
 
 void Scop::addScopStmt(Region *R, Loop *SurroundingLoop) {
   assert(R && "Unexpected nullptr!");
   Stmts.emplace_back(*this, *R, SurroundingLoop);
   auto *Stmt = &Stmts.back();
-  for (BasicBlock *BB : R->blocks())
+  for (BasicBlock *BB : R->blocks()) {
     StmtMap[BB].push_back(Stmt);
+    for (Instruction &Inst : *BB) {
+      assert(!InstStmtMap.count(&Inst) &&
+             "Unexpected statement corresponding to the instruction.");
+      InstStmtMap[&Inst] = Stmt;
+    }
+  }
 }
 
 ScopStmt *Scop::addScopStmt(__isl_take isl_map *SourceRel,