1 files changed, 53 insertions, 5 deletions

diff --git a/llvm/include/llvm/Transforms/Scalar/GVN.h b/llvm/include/llvm/Transforms/Scalar/GVN.h
index 5a3d30de16a3..f2818c6b792e 100644
--- a/llvm/include/llvm/Transforms/Scalar/GVN.h
+++ b/llvm/include/llvm/Transforms/Scalar/GVN.h
@@ -20,7 +20,6 @@
 #include "llvm/ADT/PostOrderIterator.h"
 #include "llvm/ADT/SetVector.h"
 #include "llvm/ADT/SmallVector.h"
-#include "llvm/Analysis/AliasAnalysis.h"
 #include "llvm/Analysis/InstructionPrecedenceTracking.h"
 #include "llvm/Analysis/MemoryDependenceAnalysis.h"
 #include "llvm/IR/Dominators.h"
@@ -35,6 +34,7 @@
 
 namespace llvm {
 
+class AAResults;
 class AssumptionCache;
 class BasicBlock;
 class BranchInst;
@@ -61,14 +61,57 @@ class GVNLegacyPass;
 
 } // end namespace gvn
 
+/// A set of parameters to control various transforms performed by GVN pass.
+//  Each of the optional boolean parameters can be set to:
+///      true - enabling the transformation.
+///      false - disabling the transformation.
+///      None - relying on a global default.
+/// Intended use is to create a default object, modify parameters with
+/// additional setters and then pass it to GVN.
+struct GVNOptions {
+  Optional<bool> AllowPRE = None;
+  Optional<bool> AllowLoadPRE = None;
+  Optional<bool> AllowLoadInLoopPRE = None;
+  Optional<bool> AllowMemDep = None;
+
+  GVNOptions() = default;
+
+  /// Enables or disables PRE in GVN.
+  GVNOptions &setPRE(bool PRE) {
+    AllowPRE = PRE;
+    return *this;
+  }
+
+  /// Enables or disables PRE of loads in GVN.
+  GVNOptions &setLoadPRE(bool LoadPRE) {
+    AllowLoadPRE = LoadPRE;
+    return *this;
+  }
+
+  GVNOptions &setLoadInLoopPRE(bool LoadInLoopPRE) {
+    AllowLoadInLoopPRE = LoadInLoopPRE;
+    return *this;
+  }
+
+  /// Enables or disables use of MemDepAnalysis.
+  GVNOptions &setMemDep(bool MemDep) {
+    AllowMemDep = MemDep;
+    return *this;
+  }
+};
+
 /// The core GVN pass object.
 ///
 /// FIXME: We should have a good summary of the GVN algorithm implemented by
 /// this particular pass here.
 class GVN : public PassInfoMixin<GVN> {
+  GVNOptions Options;
+
 public:
   struct Expression;
 
+  GVN(GVNOptions Options = {}) : Options(Options) {}
+
   /// Run the pass over the function.
   PreservedAnalyses run(Function &F, FunctionAnalysisManager &AM);
 
@@ -80,9 +123,14 @@ public:
   }
 
   DominatorTree &getDominatorTree() const { return *DT; }
-  AliasAnalysis *getAliasAnalysis() const { return VN.getAliasAnalysis(); }
+  AAResults *getAliasAnalysis() const { return VN.getAliasAnalysis(); }
   MemoryDependenceResults &getMemDep() const { return *MD; }
 
+  bool isPREEnabled() const;
+  bool isLoadPREEnabled() const;
+  bool isLoadInLoopPREEnabled() const;
+  bool isMemDepEnabled() const;
+
   /// This class holds the mapping between values and value numbers.  It is used
   /// as an efficient mechanism to determine the expression-wise equivalence of
   /// two values.
@@ -107,7 +155,7 @@ public:
         DenseMap<std::pair<uint32_t, const BasicBlock *>, uint32_t>;
     PhiTranslateMap PhiTranslateTable;
 
-    AliasAnalysis *AA = nullptr;
+    AAResults *AA = nullptr;
     MemoryDependenceResults *MD = nullptr;
     DominatorTree *DT = nullptr;
 
@@ -143,8 +191,8 @@ public:
     void add(Value *V, uint32_t num);
     void clear();
     void erase(Value *v);
-    void setAliasAnalysis(AliasAnalysis *A) { AA = A; }
-    AliasAnalysis *getAliasAnalysis() const { return AA; }
+    void setAliasAnalysis(AAResults *A) { AA = A; }
+    AAResults *getAliasAnalysis() const { return AA; }
     void setMemDep(MemoryDependenceResults *M) { MD = M; }
     void setDomTree(DominatorTree *D) { DT = D; }
     uint32_t getNextUnusedValueNumber() { return nextValueNumber; }