--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/lib/Target/NVPTX/NVPTXImageOptimizer.cpp	Mon Sep 08 22:06:00 2014 +0900
@@ -0,0 +1,178 @@
+//===-- NVPTXImageOptimizer.cpp - Image optimization pass -----------------===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source 
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+// This pass implements IR-level optimizations of image access code,
+// including:
+//
+// 1. Eliminate istypep intrinsics when image access qualifier is known
+//
+//===----------------------------------------------------------------------===//
+
+#include "NVPTX.h"
+#include "NVPTXUtilities.h"
+#include "llvm/IR/Instructions.h"
+#include "llvm/IR/Intrinsics.h"
+#include "llvm/IR/Module.h"
+#include "llvm/Pass.h"
+#include "llvm/Analysis/ConstantFolding.h"
+
+using namespace llvm;
+
+namespace {
+class NVPTXImageOptimizer : public FunctionPass {
+private:
+  static char ID;
+  SmallVector<Instruction*, 4> InstrToDelete;
+
+public:
+  NVPTXImageOptimizer();
+
+  bool runOnFunction(Function &F) override;
+
+private:
+  bool replaceIsTypePSampler(Instruction &I);
+  bool replaceIsTypePSurface(Instruction &I);
+  bool replaceIsTypePTexture(Instruction &I);
+  Value *cleanupValue(Value *V);
+  void replaceWith(Instruction *From, ConstantInt *To);
+};
+}
+
+char NVPTXImageOptimizer::ID = 0;
+
+NVPTXImageOptimizer::NVPTXImageOptimizer()
+  : FunctionPass(ID) {}
+
+bool NVPTXImageOptimizer::runOnFunction(Function &F) {
+  bool Changed = false;
+  InstrToDelete.clear();
+
+  // Look for call instructions in the function
+  for (Function::iterator BI = F.begin(), BE = F.end(); BI != BE;
+       ++BI) {
+    for (BasicBlock::iterator I = (*BI).begin(), E = (*BI).end();
+         I != E; ++I) {
+      Instruction &Instr = *I;
+      if (CallInst *CI = dyn_cast<CallInst>(I)) {
+        Function *CalledF = CI->getCalledFunction();
+        if (CalledF && CalledF->isIntrinsic()) {
+          // This is an intrinsic function call, check if its an istypep
+          switch (CalledF->getIntrinsicID()) {
+          default: break;
+          case Intrinsic::nvvm_istypep_sampler:
+            Changed |= replaceIsTypePSampler(Instr);
+            break;
+          case Intrinsic::nvvm_istypep_surface:
+            Changed |= replaceIsTypePSurface(Instr);
+            break;
+          case Intrinsic::nvvm_istypep_texture:
+            Changed |= replaceIsTypePTexture(Instr);
+            break;
+          }
+        }
+      }
+    }
+  }
+
+  // Delete any istypep instances we replaced in the IR
+  for (unsigned i = 0, e = InstrToDelete.size(); i != e; ++i)
+    InstrToDelete[i]->eraseFromParent();
+
+  return Changed;
+}
+
+bool NVPTXImageOptimizer::replaceIsTypePSampler(Instruction &I) {
+  Value *TexHandle = cleanupValue(I.getOperand(0));
+  if (isSampler(*TexHandle)) {
+    // This is an OpenCL sampler, so it must be a samplerref
+    replaceWith(&I, ConstantInt::getTrue(I.getContext()));
+    return true;
+  } else if (isImageWriteOnly(*TexHandle) ||
+             isImageReadWrite(*TexHandle) ||
+             isImageReadOnly(*TexHandle)) {
+    // This is an OpenCL image, so it cannot be a samplerref
+    replaceWith(&I, ConstantInt::getFalse(I.getContext()));
+    return true;
+  } else {
+    // The image type is unknown, so we cannot eliminate the intrinsic
+    return false;
+  }
+}
+
+bool NVPTXImageOptimizer::replaceIsTypePSurface(Instruction &I) {
+  Value *TexHandle = cleanupValue(I.getOperand(0));
+  if (isImageReadWrite(*TexHandle) ||
+      isImageWriteOnly(*TexHandle)) {
+    // This is an OpenCL read-only/read-write image, so it must be a surfref
+    replaceWith(&I, ConstantInt::getTrue(I.getContext()));
+    return true;
+  } else if (isImageReadOnly(*TexHandle) ||
+             isSampler(*TexHandle)) {
+    // This is an OpenCL read-only/ imageor sampler, so it cannot be
+    // a surfref
+    replaceWith(&I, ConstantInt::getFalse(I.getContext()));
+    return true;
+  } else {
+    // The image type is unknown, so we cannot eliminate the intrinsic
+    return false;
+  }
+}
+
+bool NVPTXImageOptimizer::replaceIsTypePTexture(Instruction &I) {
+  Value *TexHandle = cleanupValue(I.getOperand(0));
+  if (isImageReadOnly(*TexHandle)) {
+    // This is an OpenCL read-only image, so it must be a texref
+    replaceWith(&I, ConstantInt::getTrue(I.getContext()));
+    return true;
+  } else if (isImageWriteOnly(*TexHandle) ||
+             isImageReadWrite(*TexHandle) ||
+             isSampler(*TexHandle)) {
+    // This is an OpenCL read-write/write-only image or a sampler, so it
+    // cannot be a texref
+    replaceWith(&I, ConstantInt::getFalse(I.getContext()));
+    return true;
+  } else {
+    // The image type is unknown, so we cannot eliminate the intrinsic
+    return false;
+  }
+}
+
+void NVPTXImageOptimizer::replaceWith(Instruction *From, ConstantInt *To) {
+  // We implement "poor man's DCE" here to make sure any code that is no longer
+  // live is actually unreachable and can be trivially eliminated by the
+  // unreachable block elimination pass.
+  for (CallInst::use_iterator UI = From->use_begin(), UE = From->use_end();
+       UI != UE; ++UI) {
+    if (BranchInst *BI = dyn_cast<BranchInst>(*UI)) {
+      if (BI->isUnconditional()) continue;
+      BasicBlock *Dest;
+      if (To->isZero())
+        // Get false block
+        Dest = BI->getSuccessor(1);
+      else
+        // Get true block
+        Dest = BI->getSuccessor(0);
+      BranchInst::Create(Dest, BI);
+      InstrToDelete.push_back(BI);
+    }
+  }
+  From->replaceAllUsesWith(To);
+  InstrToDelete.push_back(From);
+}
+
+Value *NVPTXImageOptimizer::cleanupValue(Value *V) {
+  if (ExtractValueInst *EVI = dyn_cast<ExtractValueInst>(V)) {
+    return cleanupValue(EVI->getAggregateOperand());
+  }
+  return V;
+}
+
+FunctionPass *llvm::createNVPTXImageOptimizerPass() {
+  return new NVPTXImageOptimizer();
+}