[NVPTX] Add an NVPTX-specific TargetTransformInfo

Summary:
It currently only implements hasBranchDivergence, and will be extended
in later diffs.

Split from D6188.

Test Plan: make check-all

Reviewers: jholewinski

Reviewed By: jholewinski

Subscribers: llvm-commits, meheff, eliben, jholewinski

Differential Revision: http://reviews.llvm.org/D6195

llvm-svn: 221619
diff --git a/llvm/lib/Target/NVPTX/NVPTXTargetTransformInfo.cpp b/llvm/lib/Target/NVPTX/NVPTXTargetTransformInfo.cpp
new file mode 100644
index 0000000..b3a5b60
--- /dev/null
+++ b/llvm/lib/Target/NVPTX/NVPTXTargetTransformInfo.cpp
@@ -0,0 +1,90 @@
+//===-- NVPTXTargetTransformInfo.cpp - NVPTX specific TTI pass ---------===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+// \file
+// This file implements a TargetTransformInfo analysis pass specific to the
+// NVPTX target machine. It uses the target's detailed information to provide
+// more precise answers to certain TTI queries, while letting the target
+// independent and default TTI implementations handle the rest.
+//
+//===----------------------------------------------------------------------===//
+
+#include "NVPTXTargetMachine.h"
+#include "llvm/Analysis/LoopInfo.h"
+#include "llvm/Analysis/TargetTransformInfo.h"
+#include "llvm/Analysis/ValueTracking.h"
+#include "llvm/Support/Debug.h"
+#include "llvm/Target/CostTable.h"
+#include "llvm/Target/TargetLowering.h"
+using namespace llvm;
+
+#define DEBUG_TYPE "NVPTXtti"
+
+// Declare the pass initialization routine locally as target-specific passes
+// don't have a target-wide initialization entry point, and so we rely on the
+// pass constructor initialization.
+namespace llvm {
+void initializeNVPTXTTIPass(PassRegistry &);
+}
+
+namespace {
+
+class NVPTXTTI final : public ImmutablePass, public TargetTransformInfo {
+  const NVPTXTargetMachine *TM;
+  const NVPTXSubtarget *ST;
+  const NVPTXTargetLowering *TLI;
+
+  /// Estimate the overhead of scalarizing an instruction. Insert and Extract
+  /// are set if the result needs to be inserted and/or extracted from vectors.
+  unsigned getScalarizationOverhead(Type *Ty, bool Insert, bool Extract) const;
+
+public:
+  NVPTXTTI() : ImmutablePass(ID), TM(nullptr), ST(nullptr), TLI(nullptr) {
+    llvm_unreachable("This pass cannot be directly constructed");
+  }
+
+  NVPTXTTI(const NVPTXTargetMachine *TM)
+      : ImmutablePass(ID), TM(TM), ST(TM->getSubtargetImpl()),
+        TLI(TM->getSubtargetImpl()->getTargetLowering()) {
+    initializeNVPTXTTIPass(*PassRegistry::getPassRegistry());
+  }
+
+  void initializePass() override { pushTTIStack(this); }
+
+  void getAnalysisUsage(AnalysisUsage &AU) const override {
+    TargetTransformInfo::getAnalysisUsage(AU);
+  }
+
+  /// Pass identification.
+  static char ID;
+
+  /// Provide necessary pointer adjustments for the two base classes.
+  void *getAdjustedAnalysisPointer(const void *ID) override {
+    if (ID == &TargetTransformInfo::ID)
+      return (TargetTransformInfo *)this;
+    return this;
+  }
+
+  bool hasBranchDivergence() const override;
+
+  /// @}
+};
+
+} // end anonymous namespace
+
+INITIALIZE_AG_PASS(NVPTXTTI, TargetTransformInfo, "NVPTXtti",
+                   "NVPTX Target Transform Info", true, true, false)
+char NVPTXTTI::ID = 0;
+
+ImmutablePass *
+llvm::createNVPTXTargetTransformInfoPass(const NVPTXTargetMachine *TM) {
+  return new NVPTXTTI(TM);
+}
+
+bool NVPTXTTI::hasBranchDivergence() const { return true; }