diff --git a/polly/include/polly/CodeGen/BlockGenerators.h b/polly/include/polly/CodeGen/BlockGenerators.h
index f2c52c8fedcf..f02524a34254 100644
--- a/polly/include/polly/CodeGen/BlockGenerators.h
+++ b/polly/include/polly/CodeGen/BlockGenerators.h
@@ -21,7 +21,32 @@
 #include "isl/isl-noexceptions.h"
 
 namespace polly {
-using namespace llvm;
+using llvm::AllocaInst;
+using llvm::ArrayRef;
+using llvm::AssertingVH;
+using llvm::BasicBlock;
+using llvm::BinaryOperator;
+using llvm::CmpInst;
+using llvm::DataLayout;
+using llvm::DenseMap;
+using llvm::DominatorTree;
+using llvm::Function;
+using llvm::Instruction;
+using llvm::LoadInst;
+using llvm::Loop;
+using llvm::LoopInfo;
+using llvm::LoopToScevMapT;
+using llvm::MapVector;
+using llvm::PHINode;
+using llvm::ScalarEvolution;
+using llvm::SetVector;
+using llvm::SmallVector;
+using llvm::StoreInst;
+using llvm::StringRef;
+using llvm::Type;
+using llvm::UnaryInstruction;
+using llvm::Value;
+
 class MemoryAccess;
 class ScopArrayInfo;
 class IslExprBuilder;
diff --git a/polly/include/polly/CodeGen/IslAst.h b/polly/include/polly/CodeGen/IslAst.h
index 1a842b87d6d5..fc2a5e461fa1 100644
--- a/polly/include/polly/CodeGen/IslAst.h
+++ b/polly/include/polly/CodeGen/IslAst.h
@@ -27,6 +27,7 @@
 #include "isl/ctx.h"
 
 namespace polly {
+using llvm::SmallPtrSet;
 
 struct Dependences;
 
diff --git a/polly/include/polly/CodeGen/IslNodeBuilder.h b/polly/include/polly/CodeGen/IslNodeBuilder.h
index ac28af20a3d4..3177762c8802 100644
--- a/polly/include/polly/CodeGen/IslNodeBuilder.h
+++ b/polly/include/polly/CodeGen/IslNodeBuilder.h
@@ -23,13 +23,11 @@
 #include "isl/ctx.h"
 #include "isl/isl-noexceptions.h"
 
-using namespace llvm;
-using namespace polly;
-
 namespace polly {
+using llvm::LoopInfo;
+using llvm::SmallSet;
 
 struct InvariantEquivClassTy;
-} // namespace polly
 
 struct SubtreeReferences {
   LoopInfo &LI;
@@ -429,4 +427,6 @@ private:
   Value *materializeNonScopLoopInductionVariable(const Loop *L);
 };
 
+} // namespace polly
+
 #endif // POLLY_ISLNODEBUILDER_H
diff --git a/polly/include/polly/CodeGen/LoopGenerators.h b/polly/include/polly/CodeGen/LoopGenerators.h
index 09a0424525c9..bb73f229d87c 100644
--- a/polly/include/polly/CodeGen/LoopGenerators.h
+++ b/polly/include/polly/CodeGen/LoopGenerators.h
@@ -18,7 +18,17 @@
 #include "llvm/ADT/SetVector.h"
 
 namespace polly {
-using namespace llvm;
+using llvm::AllocaInst;
+using llvm::BasicBlock;
+using llvm::DataLayout;
+using llvm::DominatorTree;
+using llvm::Function;
+using llvm::ICmpInst;
+using llvm::LoopInfo;
+using llvm::Module;
+using llvm::SetVector;
+using llvm::Type;
+using llvm::Value;
 
 /// General scheduling types of parallel OpenMP for loops.
 /// Initialization values taken from OpenMP's enum in kmp.h: sched_type.
diff --git a/polly/include/polly/CodeGen/LoopGeneratorsGOMP.h b/polly/include/polly/CodeGen/LoopGeneratorsGOMP.h
index b3ff9825ff3b..1f47d38f0162 100644
--- a/polly/include/polly/CodeGen/LoopGeneratorsGOMP.h
+++ b/polly/include/polly/CodeGen/LoopGeneratorsGOMP.h
@@ -19,7 +19,6 @@
 #include "llvm/ADT/SetVector.h"
 
 namespace polly {
-using namespace llvm;
 
 /// This ParallelLoopGenerator subclass handles the generation of parallelized
 /// code, utilizing the GNU OpenMP library.
diff --git a/polly/include/polly/CodeGen/LoopGeneratorsKMP.h b/polly/include/polly/CodeGen/LoopGeneratorsKMP.h
index 470df6002bee..c4921aced766 100644
--- a/polly/include/polly/CodeGen/LoopGeneratorsKMP.h
+++ b/polly/include/polly/CodeGen/LoopGeneratorsKMP.h
@@ -19,7 +19,8 @@
 #include "llvm/ADT/SetVector.h"
 
 namespace polly {
-using namespace llvm;
+using llvm::GlobalValue;
+using llvm::GlobalVariable;
 
 /// This ParallelLoopGenerator subclass handles the generation of parallelized
 /// code, utilizing the LLVM OpenMP library.
diff --git a/polly/include/polly/DependenceInfo.h b/polly/include/polly/DependenceInfo.h
index d66be816349b..a8b11191d619 100644
--- a/polly/include/polly/DependenceInfo.h
+++ b/polly/include/polly/DependenceInfo.h
@@ -26,8 +26,6 @@
 #include "isl/ctx.h"
 #include "isl/isl-noexceptions.h"
 
-using namespace llvm;
-
 namespace polly {
 
 /// The accumulated dependence information for a SCoP.
diff --git a/polly/include/polly/ForwardOpTree.h b/polly/include/polly/ForwardOpTree.h
index dfa11bea9414..72c77c398ad5 100644
--- a/polly/include/polly/ForwardOpTree.h
+++ b/polly/include/polly/ForwardOpTree.h
@@ -22,7 +22,7 @@ void initializeForwardOpTreeWrapperPassPass(PassRegistry &);
 } // namespace llvm
 
 namespace polly {
-Pass *createForwardOpTreeWrapperPass();
+llvm::Pass *createForwardOpTreeWrapperPass();
 
 struct ForwardOpTreePass : llvm::PassInfoMixin<ForwardOpTreePass> {
   ForwardOpTreePass() {}
diff --git a/polly/include/polly/ScopBuilder.h b/polly/include/polly/ScopBuilder.h
index 7bed07c36c52..7c3a944dd5c9 100644
--- a/polly/include/polly/ScopBuilder.h
+++ b/polly/include/polly/ScopBuilder.h
@@ -22,6 +22,7 @@
 #include "llvm/ADT/SetVector.h"
 
 namespace polly {
+using llvm::SmallSetVector;
 
 class ScopDetection;
 
diff --git a/polly/include/polly/ScopDetection.h b/polly/include/polly/ScopDetection.h
index f28ab498c83f..835dd135d8c6 100644
--- a/polly/include/polly/ScopDetection.h
+++ b/polly/include/polly/ScopDetection.h
@@ -54,8 +54,6 @@
 #include "llvm/Pass.h"
 #include <set>
 
-using namespace llvm;
-
 namespace llvm {
 class AAResults;
 
@@ -63,6 +61,32 @@ void initializeScopDetectionWrapperPassPass(PassRegistry &);
 } // namespace llvm
 
 namespace polly {
+using llvm::AAResults;
+using llvm::AliasSetTracker;
+using llvm::AnalysisInfoMixin;
+using llvm::AnalysisKey;
+using llvm::AnalysisUsage;
+using llvm::BranchInst;
+using llvm::CallInst;
+using llvm::DenseMap;
+using llvm::DominatorTree;
+using llvm::Function;
+using llvm::FunctionAnalysisManager;
+using llvm::FunctionPass;
+using llvm::IntrinsicInst;
+using llvm::LoopInfo;
+using llvm::Module;
+using llvm::OptimizationRemarkEmitter;
+using llvm::PassInfoMixin;
+using llvm::PreservedAnalyses;
+using llvm::RegionInfo;
+using llvm::ScalarEvolution;
+using llvm::SCEVUnknown;
+using llvm::SetVector;
+using llvm::SmallSetVector;
+using llvm::SmallVectorImpl;
+using llvm::StringRef;
+using llvm::SwitchInst;
 
 using ParamSetType = std::set<const SCEV *>;
 
@@ -136,7 +160,7 @@ public:
     ///
     /// This set contains all base pointers and the locations where they are
     /// used for memory accesses that can not be detected as affine accesses.
-    SetVector<std::pair<const SCEVUnknown *, Loop *>> NonAffineAccesses;
+    llvm::SetVector<std::pair<const SCEVUnknown *, Loop *>> NonAffineAccesses;
     BaseToElSize ElementSize;
 
     /// The region has at least one load instruction.
diff --git a/polly/include/polly/ScopDetectionDiagnostic.h b/polly/include/polly/ScopDetectionDiagnostic.h
index 682461584617..200fb8f47d37 100644
--- a/polly/include/polly/ScopDetectionDiagnostic.h
+++ b/polly/include/polly/ScopDetectionDiagnostic.h
@@ -25,10 +25,7 @@
 #include "llvm/IR/Instruction.h"
 #include <cstddef>
 
-using namespace llvm;
-
 namespace llvm {
-
 class AliasSet;
 class BasicBlock;
 class OptimizationRemarkEmitter;
@@ -37,6 +34,17 @@ class SCEV;
 } // namespace llvm
 
 namespace polly {
+using llvm::AliasSet;
+using llvm::BasicBlock;
+using llvm::DebugLoc;
+using llvm::Instruction;
+using llvm::Loop;
+using llvm::OptimizationRemarkEmitter;
+using llvm::raw_ostream;
+using llvm::Region;
+using llvm::SCEV;
+using llvm::SmallVector;
+using llvm::Value;
 
 /// Type to hold region delimiters (entry & exit block).
 using BBPair = std::pair<BasicBlock *, BasicBlock *>;
diff --git a/polly/include/polly/ScopInfo.h b/polly/include/polly/ScopInfo.h
index dbebfb2aa40e..6ac029c32102 100644
--- a/polly/include/polly/ScopInfo.h
+++ b/polly/include/polly/ScopInfo.h
@@ -35,14 +35,42 @@
 #include <cstddef>
 #include <forward_list>
 
-using namespace llvm;
-
 namespace llvm {
 void initializeScopInfoRegionPassPass(PassRegistry &);
 void initializeScopInfoWrapperPassPass(PassRegistry &);
 } // end namespace llvm
 
 namespace polly {
+using llvm::AnalysisInfoMixin;
+using llvm::ArrayRef;
+using llvm::AssertingVH;
+using llvm::AssumptionCache;
+using llvm::cast;
+using llvm::DataLayout;
+using llvm::DenseMap;
+using llvm::DenseSet;
+using llvm::function_ref;
+using llvm::isa;
+using llvm::iterator_range;
+using llvm::LoadInst;
+using llvm::make_range;
+using llvm::MapVector;
+using llvm::MemIntrinsic;
+using llvm::Optional;
+using llvm::PassInfoMixin;
+using llvm::PHINode;
+using llvm::RegionNode;
+using llvm::RegionPass;
+using llvm::RGPassManager;
+using llvm::SetVector;
+using llvm::SmallPtrSetImpl;
+using llvm::SmallVector;
+using llvm::SmallVectorImpl;
+using llvm::StringMap;
+using llvm::Type;
+using llvm::Use;
+using llvm::Value;
+using llvm::ValueToValueMap;
 
 class MemoryAccess;
 
@@ -1212,7 +1240,7 @@ private:
   /// The memory accesses of this statement.
   ///
   /// The only side effects of a statement are its memory accesses.
-  using MemoryAccessVec = SmallVector<MemoryAccess *, 8>;
+  using MemoryAccessVec = llvm::SmallVector<MemoryAccess *, 8>;
   MemoryAccessVec MemAccs;
 
   /// Mapping from instructions to (scalar) memory accesses.
diff --git a/polly/include/polly/ScopPass.h b/polly/include/polly/ScopPass.h
index e091a39c8190..ccd6da143843 100644
--- a/polly/include/polly/ScopPass.h
+++ b/polly/include/polly/ScopPass.h
@@ -24,9 +24,20 @@
 #include "llvm/IR/PassManager.h"
 #include "llvm/IR/PassManagerImpl.h"
 
-using namespace llvm;
-
 namespace polly {
+using llvm::AllAnalysesOn;
+using llvm::AnalysisManager;
+using llvm::DominatorTreeAnalysis;
+using llvm::InnerAnalysisManagerProxy;
+using llvm::LoopAnalysis;
+using llvm::OuterAnalysisManagerProxy;
+using llvm::PassManager;
+using llvm::RegionInfoAnalysis;
+using llvm::ScalarEvolutionAnalysis;
+using llvm::SmallPriorityWorklist;
+using llvm::TargetIRAnalysis;
+using llvm::TargetTransformInfo;
+
 class Scop;
 class SPMUpdater;
 struct ScopStandardAnalysisResults;
diff --git a/polly/include/polly/Support/VirtualInstruction.h b/polly/include/polly/Support/VirtualInstruction.h
index 90bf04f5bf46..4faf66e6caf9 100644
--- a/polly/include/polly/Support/VirtualInstruction.h
+++ b/polly/include/polly/Support/VirtualInstruction.h
@@ -17,6 +17,7 @@
 #include "polly/ScopInfo.h"
 
 namespace polly {
+using llvm::User;
 
 /// Determine the nature of a value's use within a statement.
 ///
diff --git a/polly/lib/CodeGen/IslNodeBuilder.cpp b/polly/lib/CodeGen/IslNodeBuilder.cpp
index a329661feddf..688618e23be0 100644
--- a/polly/lib/CodeGen/IslNodeBuilder.cpp
+++ b/polly/lib/CodeGen/IslNodeBuilder.cpp
@@ -225,8 +225,8 @@ static int findReferencesInBlock(struct SubtreeReferences &References,
   return 0;
 }
 
-void addReferencesFromStmt(const ScopStmt *Stmt, void *UserPtr,
-                           bool CreateScalarRefs) {
+void polly::addReferencesFromStmt(const ScopStmt *Stmt, void *UserPtr,
+                                  bool CreateScalarRefs) {
   auto &References = *static_cast<struct SubtreeReferences *>(UserPtr);
 
   if (Stmt->isBlockStmt())
diff --git a/polly/lib/CodeGen/ManagedMemoryRewrite.cpp b/polly/lib/CodeGen/ManagedMemoryRewrite.cpp
index 72ad0264b5bd..64bfa8dd8b1b 100644
--- a/polly/lib/CodeGen/ManagedMemoryRewrite.cpp
+++ b/polly/lib/CodeGen/ManagedMemoryRewrite.cpp
@@ -26,6 +26,7 @@
 #include "llvm/InitializePasses.h"
 #include "llvm/Transforms/Utils/ModuleUtils.h"
 
+using namespace llvm;
 using namespace polly;
 
 static cl::opt<bool> RewriteAllocas(
diff --git a/polly/lib/Transform/ScopInliner.cpp b/polly/lib/Transform/ScopInliner.cpp
index 3d0737f13cde..83c3b8d350ba 100644
--- a/polly/lib/Transform/ScopInliner.cpp
+++ b/polly/lib/Transform/ScopInliner.cpp
@@ -23,7 +23,9 @@
 
 #define DEBUG_TYPE "polly-scop-inliner"
 
+using namespace llvm;
 using namespace polly;
+
 extern bool polly::PollyAllowFullFunction;
 
 namespace {