[AMDGPU] Add address space based alias analysis pass

This is direct port of HSAILAliasAnalysis pass, just cleaned for
style and renamed.

Differential Revision: https://reviews.llvm.org/D31103

llvm-svn: 298172

1 files changed, 86 insertions, 0 deletions

diff --git a/llvm/lib/Target/AMDGPU/AMDGPUAliasAnalysis.h b/llvm/lib/Target/AMDGPU/AMDGPUAliasAnalysis.h
new file mode 100644
index 00000000000..943b4a68b25
--- /dev/null
+++ b/llvm/lib/Target/AMDGPU/AMDGPUAliasAnalysis.h
@@ -0,0 +1,86 @@
+//===- AMDGPUAliasAnalysis ---------------------------------------*- C++ -*-==//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+/// \file
+/// This is the AMGPU address space based alias analysis pass.
+//===----------------------------------------------------------------------===//
+
+#ifndef LLVM_ANALYSIS_AMDGPUALIASANALYSIS_H
+#define LLVM_ANALYSIS_AMDGPUALIASANALYSIS_H
+
+#include "llvm/Analysis/AliasAnalysis.h"
+#include "llvm/IR/Function.h"
+#include "llvm/IR/Module.h"
+#include "llvm/Pass.h"
+
+namespace llvm {
+
+/// A simple AA result that uses TBAA metadata to answer queries.
+class AMDGPUAAResult : public AAResultBase<AMDGPUAAResult> {
+  friend AAResultBase<AMDGPUAAResult>;
+
+  const DataLayout &DL;
+
+public:
+  explicit AMDGPUAAResult(const DataLayout &DL) : AAResultBase(), DL(DL) {}
+  AMDGPUAAResult(AMDGPUAAResult &&Arg)
+      : AAResultBase(std::move(Arg)), DL(Arg.DL){}
+
+  /// Handle invalidation events from the new pass manager.
+  ///
+  /// By definition, this result is stateless and so remains valid.
+  bool invalidate(Function &, const PreservedAnalyses &) { return false; }
+
+  AliasResult alias(const MemoryLocation &LocA, const MemoryLocation &LocB);
+  bool pointsToConstantMemory(const MemoryLocation &Loc, bool OrLocal);
+
+private:
+  bool Aliases(const MDNode *A, const MDNode *B) const;
+  bool PathAliases(const MDNode *A, const MDNode *B) const;
+};
+
+/// Analysis pass providing a never-invalidated alias analysis result.
+class AMDGPUAA : public AnalysisInfoMixin<AMDGPUAA> {
+  friend AnalysisInfoMixin<AMDGPUAA>;
+  static char PassID;
+
+public:
+  typedef AMDGPUAAResult Result;
+
+  AMDGPUAAResult run(Function &F, AnalysisManager<Function> &AM) {
+    return AMDGPUAAResult(F.getParent()->getDataLayout());
+  }
+};
+
+/// Legacy wrapper pass to provide the AMDGPUAAResult object.
+class AMDGPUAAWrapperPass : public ImmutablePass {
+  std::unique_ptr<AMDGPUAAResult> Result;
+
+public:
+  static char ID;
+
+  AMDGPUAAWrapperPass() : ImmutablePass(ID) {
+    initializeAMDGPUAAWrapperPassPass(*PassRegistry::getPassRegistry());
+  }
+
+  AMDGPUAAResult &getResult() { return *Result; }
+  const AMDGPUAAResult &getResult() const { return *Result; }
+
+  bool doInitialization(Module &M) override {
+    Result.reset(new AMDGPUAAResult(M.getDataLayout()));
+    return false;
+  }
+  bool doFinalization(Module &M) override {
+    Result.reset();
+    return false;
+  }
+  void getAnalysisUsage(AnalysisUsage &AU) const override;
+};
+
+}
+#endif // LLVM_ANALYSIS_AMDGPUALIASANALYSIS_H