lib/Target/AMDGPU/AMDGPUImageIntrinsicOptimizer.cpp - llvm-project/llvm - Git at Google

 //===- AMDGPUImageIntrinsicOptimizer.cpp ----------------------------------===//
 //
 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
 // See https://llvm.org/LICENSE.txt for license information.
 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
 //
 //===----------------------------------------------------------------------===//
 //
 // This pass tries to combine multiple image_load intrinsics with dim=2dmsaa
 // or dim=2darraymsaa into a single image_msaa_load intrinsic if:
 //
 // - they refer to the same vaddr except for sample_id,
 // - they use a constant sample_id and they fall into the same group,
 // - they have the same dmask and the number of intrinsics and the number of
 //   vaddr/vdata dword transfers is reduced by the combine.
 //
 // Examples for the tradeoff (all are assuming 2DMsaa for vaddr):
 //
 // +----------+-----+-----+-------+---------+------------+---------+----------+
 // | popcount | a16 | d16 | #load | vaddr / | #msaa_load | vaddr / | combine? |
 // |  (dmask) |     |     |       | vdata   |            | vdata   |          |
 // +----------+-----+-----+-------+---------+------------+---------+----------+
 // |        1 |   0 |   0 |     4 |  12 / 4 |          1 |   3 / 4 | yes      |
 // +----------+-----+-----+-------+---------+------------+---------+----------+
 // |        1 |   0 |   0 |     2 |   6 / 2 |          1 |   3 / 4 | yes?     |
 // +----------+-----+-----+-------+---------+------------+---------+----------+
 // |        2 |   0 |   0 |     4 |  12 / 8 |          2 |   6 / 8 | yes      |
 // +----------+-----+-----+-------+---------+------------+---------+----------+
 // |        2 |   0 |   0 |     2 |   6 / 4 |          2 |   6 / 8 | no       |
 // +----------+-----+-----+-------+---------+------------+---------+----------+
 // |        1 |   0 |   1 |     2 |   6 / 2 |          1 |   3 / 2 | yes      |
 // +----------+-----+-----+-------+---------+------------+---------+----------+
 //
 // Some cases are of questionable benefit, like the one marked with "yes?"
 // above: fewer intrinsics and fewer vaddr and fewer total transfers between SP
 // and TX, but higher vdata. We start by erring on the side of converting these
 // to MSAA_LOAD.
 //
 // clang-format off
 //
 // This pass will combine intrinsics such as (not neccessarily consecutive):
 //  call float @llvm.amdgcn.image.load.2dmsaa.f32.i32(i32 1, i32 %s, i32 %t, i32 0, <8 x i32> %rsrc, i32 0, i32 0)
 //  call float @llvm.amdgcn.image.load.2dmsaa.f32.i32(i32 1, i32 %s, i32 %t, i32 1, <8 x i32> %rsrc, i32 0, i32 0)
 //  call float @llvm.amdgcn.image.load.2dmsaa.f32.i32(i32 1, i32 %s, i32 %t, i32 2, <8 x i32> %rsrc, i32 0, i32 0)
 //  call float @llvm.amdgcn.image.load.2dmsaa.f32.i32(i32 1, i32 %s, i32 %t, i32 3, <8 x i32> %rsrc, i32 0, i32 0)
 // ==>
 //  call <4 x float> @llvm.amdgcn.image.msaa.load.2dmsaa.v4f32.i32(i32 1, i32 %s, i32 %t, i32 0, <8 x i32> %rsrc, i32 0, i32 0)
 //
 // clang-format on
 //
 // Future improvements:
 //
 // - We may occasionally not want to do the combine if it increases the maximum
 //   register pressure.
 //
 // - Ensure clausing when multiple MSAA_LOAD are generated.
 //
 // Note: Even though the image_msaa_load intrinsic already exists on gfx10, this
 // combine only applies to gfx11, due to a limitation in gfx10: the gfx10
 // IMAGE_MSAA_LOAD only works correctly with single-channel texture formats, and
 // we don't know the format at compile time.
 //===----------------------------------------------------------------------===//

 #include "AMDGPU.h"
 #include "AMDGPUInstrInfo.h"
 #include "AMDGPUTargetMachine.h"
 #include "llvm/IR/Function.h"
 #include "llvm/IR/IRBuilder.h"
 #include "llvm/IR/IntrinsicInst.h"
 #include "llvm/IR/IntrinsicsAMDGPU.h"
 #include "llvm/Pass.h"
 #include "llvm/Support/raw_ostream.h"

 using namespace llvm;

 #define DEBUG_TYPE "amdgpu-image-intrinsic-opt"

 namespace {
 class AMDGPUImageIntrinsicOptimizer : public FunctionPass {
   const TargetMachine *TM;

 public:
   static char ID;

   AMDGPUImageIntrinsicOptimizer(const TargetMachine *TM = nullptr)
       : FunctionPass(ID), TM(TM) {}

   bool runOnFunction(Function &F) override;

 }; // End of class AMDGPUImageIntrinsicOptimizer
 } // End anonymous namespace

 INITIALIZE_PASS(AMDGPUImageIntrinsicOptimizer, DEBUG_TYPE,
                 "AMDGPU Image Intrinsic Optimizer", false, false)

 char AMDGPUImageIntrinsicOptimizer::ID = 0;

 void addInstToMergeableList(
     IntrinsicInst *II,
     SmallVector<SmallVector<IntrinsicInst *, 4>> &MergeableInsts,
     const AMDGPU::ImageDimIntrinsicInfo *ImageDimIntr) {
   for (SmallVector<IntrinsicInst *, 4> &IIList : MergeableInsts) {
     // Check Dim.
     if (IIList.front()->getIntrinsicID() != II->getIntrinsicID())
       continue;

     // Check D16.
     if (IIList.front()->getType() != II->getType())
       continue;

     // Check all arguments (DMask, VAddr, RSrc etc).
     bool AllEqual = true;
     assert(IIList.front()->arg_size() == II->arg_size());
     for (int I = 1, E = II->arg_size(); AllEqual && I != E; ++I) {
       Value *ArgList = IIList.front()->getArgOperand(I);
       Value *Arg = II->getArgOperand(I);
       if (I == ImageDimIntr->VAddrEnd - 1) {
         // Check FragId group.
         auto FragIdList = cast<ConstantInt>(IIList.front()->getArgOperand(I));
         auto FragId = cast<ConstantInt>(II->getArgOperand(I));
         AllEqual = FragIdList->getValue().udiv(4) == FragId->getValue().udiv(4);
       } else {
         // Check all arguments except FragId.
         AllEqual = ArgList == Arg;
       }
     }
     if (!AllEqual)
       continue;

     // Add to the list.
     IIList.emplace_back(II);
     return;
   }

   // Similar instruction not found, so add a new list.
   MergeableInsts.emplace_back(1, II);
   LLVM_DEBUG(dbgs() << "New: " << *II << "\n");
 }

 // Collect list of all instructions we know how to merge in a subset of the
 // block. It returns an iterator to the instruction after the last one analyzed.
 BasicBlock::iterator collectMergeableInsts(
     BasicBlock::iterator I, BasicBlock::iterator E,
     SmallVector<SmallVector<IntrinsicInst *, 4>> &MergeableInsts) {
   for (; I != E; ++I) {
     // Don't combine if there is a store in the middle or if there is a memory
     // barrier.
     if (I->mayHaveSideEffects()) {
       ++I;
       break;
     }

     // Ignore non-intrinsics.
     if (IntrinsicInst *II = dyn_cast<IntrinsicInst>(I)) {
       Intrinsic::ID IntrinID = II->getIntrinsicID();

       // Ignore other intrinsics.
       if (IntrinID != Intrinsic::amdgcn_image_load_2dmsaa &&
           IntrinID != Intrinsic::amdgcn_image_load_2darraymsaa)
         continue;

       // Check for constant FragId.
       const auto *ImageDimIntr = AMDGPU::getImageDimIntrinsicInfo(IntrinID);
       const uint8_t FragIdIndex = ImageDimIntr->VAddrEnd - 1;
       if (!isa<ConstantInt>(II->getArgOperand(FragIdIndex)))
         continue;

       LLVM_DEBUG(dbgs() << "Merge: " << *II << "\n");
       addInstToMergeableList(II, MergeableInsts, ImageDimIntr);
     }
   }

   return I;
 }

 bool optimizeSection(ArrayRef<SmallVector<IntrinsicInst *, 4>> MergeableInsts) {
   bool Modified = false;

   SmallVector<Instruction *, 4> InstrsToErase;
   for (const auto &IIList : MergeableInsts) {
     if (IIList.size() <= 1)
       continue;

     // Assume the arguments are unchanged and later override them, if needed.
     SmallVector<Value *, 16> Args(IIList.front()->args());

     // Validate function argument and return types, extracting overloaded
     // types along the way.
     SmallVector<Type *, 6> OverloadTys;
     Function *F = IIList.front()->getCalledFunction();
     if (!Intrinsic::getIntrinsicSignature(F, OverloadTys))
       continue;

     Intrinsic::ID IntrinID = IIList.front()->getIntrinsicID();
     const AMDGPU::ImageDimIntrinsicInfo *ImageDimIntr =
         AMDGPU::getImageDimIntrinsicInfo(IntrinID);

     Type *EltTy = IIList.front()->getType()->getScalarType();
     Type *NewTy = FixedVectorType::get(EltTy, 4);
     OverloadTys[0] = NewTy;
     bool isD16 = EltTy->isHalfTy();

     ConstantInt *DMask = cast<ConstantInt>(
         IIList.front()->getArgOperand(ImageDimIntr->DMaskIndex));
     unsigned DMaskVal = DMask->getZExtValue() & 0xf;
     unsigned NumElts = popcount(DMaskVal);

     // Number of instructions and the number of vaddr/vdata dword transfers
     // should be reduced.
     unsigned NumLoads = IIList.size();
     unsigned NumMsaas = NumElts;
     unsigned NumVAddrLoads = 3 * NumLoads;
     unsigned NumVDataLoads = divideCeil(NumElts, isD16 ? 2 : 1) * NumLoads;
     unsigned NumVAddrMsaas = 3 * NumMsaas;
     unsigned NumVDataMsaas = divideCeil(4, isD16 ? 2 : 1) * NumMsaas;

     if (NumLoads < NumMsaas ||
         (NumVAddrLoads + NumVDataLoads < NumVAddrMsaas + NumVDataMsaas))
       continue;

     const uint8_t FragIdIndex = ImageDimIntr->VAddrEnd - 1;
     auto FragId = cast<ConstantInt>(IIList.front()->getArgOperand(FragIdIndex));
     const APInt &NewFragIdVal = FragId->getValue().udiv(4) * 4;

     // Create the new instructions.
     IRBuilder<> B(IIList.front());

     // Create the new image_msaa_load intrinsic.
     SmallVector<Instruction *, 4> NewCalls;
     while (DMaskVal != 0) {
       unsigned NewMaskVal = 1 << countr_zero(DMaskVal);

       Intrinsic::ID NewIntrinID;
       if (IntrinID == Intrinsic::amdgcn_image_load_2dmsaa)
         NewIntrinID = Intrinsic::amdgcn_image_msaa_load_2dmsaa;
       else
         NewIntrinID = Intrinsic::amdgcn_image_msaa_load_2darraymsaa;

       Function *NewIntrin = Intrinsic::getDeclaration(
           IIList.front()->getModule(), NewIntrinID, OverloadTys);
       Args[ImageDimIntr->DMaskIndex] =
           ConstantInt::get(DMask->getType(), NewMaskVal);
       Args[FragIdIndex] = ConstantInt::get(FragId->getType(), NewFragIdVal);
       CallInst *NewCall = B.CreateCall(NewIntrin, Args);
       LLVM_DEBUG(dbgs() << "Optimize: " << *NewCall << "\n");

       NewCalls.push_back(NewCall);
       DMaskVal -= NewMaskVal;
     }

     // Create the new extractelement instructions.
     for (auto &II : IIList) {
       Value *VecOp = nullptr;
       auto Idx = cast<ConstantInt>(II->getArgOperand(FragIdIndex));
       B.SetCurrentDebugLocation(II->getDebugLoc());
       if (NumElts == 1) {
         VecOp = B.CreateExtractElement(NewCalls[0], Idx->getValue().urem(4));
         LLVM_DEBUG(dbgs() << "Add: " << *VecOp << "\n");
       } else {
         VecOp = UndefValue::get(II->getType());
         for (unsigned I = 0; I < NumElts; ++I) {
           VecOp = B.CreateInsertElement(
               VecOp,
               B.CreateExtractElement(NewCalls[I], Idx->getValue().urem(4)), I);
           LLVM_DEBUG(dbgs() << "Add: " << *VecOp << "\n");
         }
       }

       // Replace the old instruction.
       II->replaceAllUsesWith(VecOp);
       VecOp->takeName(II);
       InstrsToErase.push_back(II);
     }

     Modified = true;
   }

   for (auto I : InstrsToErase)
     I->eraseFromParent();

   return Modified;
 }

 static bool imageIntrinsicOptimizerImpl(Function &F, const TargetMachine *TM) {
   if (!TM)
     return false;

   // This optimization only applies to GFX11 and beyond.
   const GCNSubtarget &ST = TM->getSubtarget<GCNSubtarget>(F);
   if (!AMDGPU::isGFX11Plus(ST) || ST.hasMSAALoadDstSelBug())
     return false;

   Module *M = F.getParent();

   // Early test to determine if the intrinsics are used.
   if (llvm::none_of(*M, [](Function &F) {
         return !F.users().empty() &&
                (F.getIntrinsicID() == Intrinsic::amdgcn_image_load_2dmsaa ||
                 F.getIntrinsicID() == Intrinsic::amdgcn_image_load_2darraymsaa);
       }))
     return false;

   bool Modified = false;
   for (auto &BB : F) {
     BasicBlock::iterator SectionEnd;
     for (BasicBlock::iterator I = BB.begin(), E = BB.end(); I != E;
          I = SectionEnd) {
       SmallVector<SmallVector<IntrinsicInst *, 4>> MergeableInsts;

       SectionEnd = collectMergeableInsts(I, E, MergeableInsts);
       Modified |= optimizeSection(MergeableInsts);
     }
   }

   return Modified;
 }

 bool AMDGPUImageIntrinsicOptimizer::runOnFunction(Function &F) {
   if (skipFunction(F))
     return false;

   return imageIntrinsicOptimizerImpl(F, TM);
 }

 FunctionPass *
 llvm::createAMDGPUImageIntrinsicOptimizerPass(const TargetMachine *TM) {
   return new AMDGPUImageIntrinsicOptimizer(TM);
 }

 PreservedAnalyses
 AMDGPUImageIntrinsicOptimizerPass::run(Function &F,
                                        FunctionAnalysisManager &AM) {

   bool Changed = imageIntrinsicOptimizerImpl(F, &TM);
   return Changed ? PreservedAnalyses::none() : PreservedAnalyses::all();
 }
	//===- AMDGPUImageIntrinsicOptimizer.cpp ----------------------------------===//
	//
	// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
	// See https://llvm.org/LICENSE.txt for license information.
	// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
	//
	//===----------------------------------------------------------------------===//
	//
	// This pass tries to combine multiple image_load intrinsics with dim=2dmsaa
	// or dim=2darraymsaa into a single image_msaa_load intrinsic if:
	//
	// - they refer to the same vaddr except for sample_id,
	// - they use a constant sample_id and they fall into the same group,
	// - they have the same dmask and the number of intrinsics and the number of
	// vaddr/vdata dword transfers is reduced by the combine.
	//
	// Examples for the tradeoff (all are assuming 2DMsaa for vaddr):
	//
	// +----------+-----+-----+-------+---------+------------+---------+----------+
	// \| popcount \| a16 \| d16 \| #load \| vaddr / \| #msaa_load \| vaddr / \| combine? \|
	// \| (dmask) \| \| \| \| vdata \| \| vdata \| \|
	// +----------+-----+-----+-------+---------+------------+---------+----------+
	// \| 1 \| 0 \| 0 \| 4 \| 12 / 4 \| 1 \| 3 / 4 \| yes \|
	// +----------+-----+-----+-------+---------+------------+---------+----------+
	// \| 1 \| 0 \| 0 \| 2 \| 6 / 2 \| 1 \| 3 / 4 \| yes? \|
	// +----------+-----+-----+-------+---------+------------+---------+----------+
	// \| 2 \| 0 \| 0 \| 4 \| 12 / 8 \| 2 \| 6 / 8 \| yes \|
	// +----------+-----+-----+-------+---------+------------+---------+----------+
	// \| 2 \| 0 \| 0 \| 2 \| 6 / 4 \| 2 \| 6 / 8 \| no \|
	// +----------+-----+-----+-------+---------+------------+---------+----------+
	// \| 1 \| 0 \| 1 \| 2 \| 6 / 2 \| 1 \| 3 / 2 \| yes \|
	// +----------+-----+-----+-------+---------+------------+---------+----------+
	//
	// Some cases are of questionable benefit, like the one marked with "yes?"
	// above: fewer intrinsics and fewer vaddr and fewer total transfers between SP
	// and TX, but higher vdata. We start by erring on the side of converting these
	// to MSAA_LOAD.
	//
	// clang-format off
	//
	// This pass will combine intrinsics such as (not neccessarily consecutive):
	// call float @llvm.amdgcn.image.load.2dmsaa.f32.i32(i32 1, i32 %s, i32 %t, i32 0, <8 x i32> %rsrc, i32 0, i32 0)
	// call float @llvm.amdgcn.image.load.2dmsaa.f32.i32(i32 1, i32 %s, i32 %t, i32 1, <8 x i32> %rsrc, i32 0, i32 0)
	// call float @llvm.amdgcn.image.load.2dmsaa.f32.i32(i32 1, i32 %s, i32 %t, i32 2, <8 x i32> %rsrc, i32 0, i32 0)
	// call float @llvm.amdgcn.image.load.2dmsaa.f32.i32(i32 1, i32 %s, i32 %t, i32 3, <8 x i32> %rsrc, i32 0, i32 0)
	// ==>
	// call <4 x float> @llvm.amdgcn.image.msaa.load.2dmsaa.v4f32.i32(i32 1, i32 %s, i32 %t, i32 0, <8 x i32> %rsrc, i32 0, i32 0)
	//
	// clang-format on
	//
	// Future improvements:
	//
	// - We may occasionally not want to do the combine if it increases the maximum
	// register pressure.
	//
	// - Ensure clausing when multiple MSAA_LOAD are generated.
	//
	// Note: Even though the image_msaa_load intrinsic already exists on gfx10, this
	// combine only applies to gfx11, due to a limitation in gfx10: the gfx10
	// IMAGE_MSAA_LOAD only works correctly with single-channel texture formats, and
	// we don't know the format at compile time.
	//===----------------------------------------------------------------------===//

	#include "AMDGPU.h"
	#include "AMDGPUInstrInfo.h"
	#include "AMDGPUTargetMachine.h"
	#include "llvm/IR/Function.h"
	#include "llvm/IR/IRBuilder.h"
	#include "llvm/IR/IntrinsicInst.h"
	#include "llvm/IR/IntrinsicsAMDGPU.h"
	#include "llvm/Pass.h"
	#include "llvm/Support/raw_ostream.h"

	using namespace llvm;

	#define DEBUG_TYPE "amdgpu-image-intrinsic-opt"

	namespace {
	class AMDGPUImageIntrinsicOptimizer : public FunctionPass {
	const TargetMachine *TM;

	public:
	static char ID;

	AMDGPUImageIntrinsicOptimizer(const TargetMachine *TM = nullptr)
	: FunctionPass(ID), TM(TM) {}

	bool runOnFunction(Function &F) override;

	}; // End of class AMDGPUImageIntrinsicOptimizer
	} // End anonymous namespace

	INITIALIZE_PASS(AMDGPUImageIntrinsicOptimizer, DEBUG_TYPE,
	"AMDGPU Image Intrinsic Optimizer", false, false)

	char AMDGPUImageIntrinsicOptimizer::ID = 0;

	void addInstToMergeableList(
	IntrinsicInst *II,
	SmallVector<SmallVector<IntrinsicInst *, 4>> &MergeableInsts,
	const AMDGPU::ImageDimIntrinsicInfo *ImageDimIntr) {
	for (SmallVector<IntrinsicInst *, 4> &IIList : MergeableInsts) {
	// Check Dim.
	if (IIList.front()->getIntrinsicID() != II->getIntrinsicID())
	continue;

	// Check D16.
	if (IIList.front()->getType() != II->getType())
	continue;

	// Check all arguments (DMask, VAddr, RSrc etc).
	bool AllEqual = true;
	assert(IIList.front()->arg_size() == II->arg_size());
	for (int I = 1, E = II->arg_size(); AllEqual && I != E; ++I) {
	Value *ArgList = IIList.front()->getArgOperand(I);
	Value *Arg = II->getArgOperand(I);
	if (I == ImageDimIntr->VAddrEnd - 1) {
	// Check FragId group.
	auto FragIdList = cast<ConstantInt>(IIList.front()->getArgOperand(I));
	auto FragId = cast<ConstantInt>(II->getArgOperand(I));
	AllEqual = FragIdList->getValue().udiv(4) == FragId->getValue().udiv(4);
	} else {
	// Check all arguments except FragId.
	AllEqual = ArgList == Arg;
	}
	}
	if (!AllEqual)
	continue;

	// Add to the list.
	IIList.emplace_back(II);
	return;
	}

	// Similar instruction not found, so add a new list.
	MergeableInsts.emplace_back(1, II);
	LLVM_DEBUG(dbgs() << "New: " << *II << "\n");
	}

	// Collect list of all instructions we know how to merge in a subset of the
	// block. It returns an iterator to the instruction after the last one analyzed.
	BasicBlock::iterator collectMergeableInsts(
	BasicBlock::iterator I, BasicBlock::iterator E,
	SmallVector<SmallVector<IntrinsicInst *, 4>> &MergeableInsts) {
	for (; I != E; ++I) {
	// Don't combine if there is a store in the middle or if there is a memory
	// barrier.
	if (I->mayHaveSideEffects()) {
	++I;
	break;
	}

	// Ignore non-intrinsics.
	if (IntrinsicInst *II = dyn_cast<IntrinsicInst>(I)) {
	Intrinsic::ID IntrinID = II->getIntrinsicID();

	// Ignore other intrinsics.
	if (IntrinID != Intrinsic::amdgcn_image_load_2dmsaa &&
	IntrinID != Intrinsic::amdgcn_image_load_2darraymsaa)
	continue;

	// Check for constant FragId.
	const auto *ImageDimIntr = AMDGPU::getImageDimIntrinsicInfo(IntrinID);
	const uint8_t FragIdIndex = ImageDimIntr->VAddrEnd - 1;
	if (!isa<ConstantInt>(II->getArgOperand(FragIdIndex)))
	continue;

	LLVM_DEBUG(dbgs() << "Merge: " << *II << "\n");
	addInstToMergeableList(II, MergeableInsts, ImageDimIntr);
	}
	}

	return I;
	}

	bool optimizeSection(ArrayRef<SmallVector<IntrinsicInst *, 4>> MergeableInsts) {
	bool Modified = false;

	SmallVector<Instruction *, 4> InstrsToErase;
	for (const auto &IIList : MergeableInsts) {
	if (IIList.size() <= 1)
	continue;

	// Assume the arguments are unchanged and later override them, if needed.
	SmallVector<Value *, 16> Args(IIList.front()->args());

	// Validate function argument and return types, extracting overloaded
	// types along the way.
	SmallVector<Type *, 6> OverloadTys;
	Function *F = IIList.front()->getCalledFunction();
	if (!Intrinsic::getIntrinsicSignature(F, OverloadTys))
	continue;

	Intrinsic::ID IntrinID = IIList.front()->getIntrinsicID();
	const AMDGPU::ImageDimIntrinsicInfo *ImageDimIntr =
	AMDGPU::getImageDimIntrinsicInfo(IntrinID);

	Type *EltTy = IIList.front()->getType()->getScalarType();
	Type *NewTy = FixedVectorType::get(EltTy, 4);
	OverloadTys[0] = NewTy;
	bool isD16 = EltTy->isHalfTy();

	ConstantInt *DMask = cast<ConstantInt>(
	IIList.front()->getArgOperand(ImageDimIntr->DMaskIndex));
	unsigned DMaskVal = DMask->getZExtValue() & 0xf;
	unsigned NumElts = popcount(DMaskVal);

	// Number of instructions and the number of vaddr/vdata dword transfers
	// should be reduced.
	unsigned NumLoads = IIList.size();
	unsigned NumMsaas = NumElts;
	unsigned NumVAddrLoads = 3 * NumLoads;
	unsigned NumVDataLoads = divideCeil(NumElts, isD16 ? 2 : 1) * NumLoads;
	unsigned NumVAddrMsaas = 3 * NumMsaas;
	unsigned NumVDataMsaas = divideCeil(4, isD16 ? 2 : 1) * NumMsaas;

	if (NumLoads < NumMsaas \|\|
	(NumVAddrLoads + NumVDataLoads < NumVAddrMsaas + NumVDataMsaas))
	continue;

	const uint8_t FragIdIndex = ImageDimIntr->VAddrEnd - 1;
	auto FragId = cast<ConstantInt>(IIList.front()->getArgOperand(FragIdIndex));
	const APInt &NewFragIdVal = FragId->getValue().udiv(4) * 4;

	// Create the new instructions.
	IRBuilder<> B(IIList.front());

	// Create the new image_msaa_load intrinsic.
	SmallVector<Instruction *, 4> NewCalls;
	while (DMaskVal != 0) {
	unsigned NewMaskVal = 1 << countr_zero(DMaskVal);

	Intrinsic::ID NewIntrinID;
	if (IntrinID == Intrinsic::amdgcn_image_load_2dmsaa)
	NewIntrinID = Intrinsic::amdgcn_image_msaa_load_2dmsaa;
	else
	NewIntrinID = Intrinsic::amdgcn_image_msaa_load_2darraymsaa;

	Function *NewIntrin = Intrinsic::getDeclaration(
	IIList.front()->getModule(), NewIntrinID, OverloadTys);
	Args[ImageDimIntr->DMaskIndex] =
	ConstantInt::get(DMask->getType(), NewMaskVal);
	Args[FragIdIndex] = ConstantInt::get(FragId->getType(), NewFragIdVal);
	CallInst *NewCall = B.CreateCall(NewIntrin, Args);
	LLVM_DEBUG(dbgs() << "Optimize: " << *NewCall << "\n");

	NewCalls.push_back(NewCall);
	DMaskVal -= NewMaskVal;
	}

	// Create the new extractelement instructions.
	for (auto &II : IIList) {
	Value *VecOp = nullptr;
	auto Idx = cast<ConstantInt>(II->getArgOperand(FragIdIndex));
	B.SetCurrentDebugLocation(II->getDebugLoc());
	if (NumElts == 1) {
	VecOp = B.CreateExtractElement(NewCalls[0], Idx->getValue().urem(4));
	LLVM_DEBUG(dbgs() << "Add: " << *VecOp << "\n");
	} else {
	VecOp = UndefValue::get(II->getType());
	for (unsigned I = 0; I < NumElts; ++I) {
	VecOp = B.CreateInsertElement(
	VecOp,
	B.CreateExtractElement(NewCalls[I], Idx->getValue().urem(4)), I);
	LLVM_DEBUG(dbgs() << "Add: " << *VecOp << "\n");
	}
	}

	// Replace the old instruction.
	II->replaceAllUsesWith(VecOp);
	VecOp->takeName(II);
	InstrsToErase.push_back(II);
	}

	Modified = true;
	}

	for (auto I : InstrsToErase)
	I->eraseFromParent();

	return Modified;
	}

	static bool imageIntrinsicOptimizerImpl(Function &F, const TargetMachine *TM) {
	if (!TM)
	return false;

	// This optimization only applies to GFX11 and beyond.
	const GCNSubtarget &ST = TM->getSubtarget<GCNSubtarget>(F);
	if (!AMDGPU::isGFX11Plus(ST) \|\| ST.hasMSAALoadDstSelBug())
	return false;

	Module *M = F.getParent();

	// Early test to determine if the intrinsics are used.
	if (llvm::none_of(*M, [](Function &F) {
	return !F.users().empty() &&
	(F.getIntrinsicID() == Intrinsic::amdgcn_image_load_2dmsaa \|\|
	F.getIntrinsicID() == Intrinsic::amdgcn_image_load_2darraymsaa);
	}))
	return false;

	bool Modified = false;
	for (auto &BB : F) {
	BasicBlock::iterator SectionEnd;
	for (BasicBlock::iterator I = BB.begin(), E = BB.end(); I != E;
	I = SectionEnd) {
	SmallVector<SmallVector<IntrinsicInst *, 4>> MergeableInsts;

	SectionEnd = collectMergeableInsts(I, E, MergeableInsts);
	Modified \|= optimizeSection(MergeableInsts);
	}
	}

	return Modified;
	}

	bool AMDGPUImageIntrinsicOptimizer::runOnFunction(Function &F) {
	if (skipFunction(F))
	return false;

	return imageIntrinsicOptimizerImpl(F, TM);
	}

	FunctionPass *
	llvm::createAMDGPUImageIntrinsicOptimizerPass(const TargetMachine *TM) {
	return new AMDGPUImageIntrinsicOptimizer(TM);
	}

	PreservedAnalyses
	AMDGPUImageIntrinsicOptimizerPass::run(Function &F,
	FunctionAnalysisManager &AM) {

	bool Changed = imageIntrinsicOptimizerImpl(F, &TM);
	return Changed ? PreservedAnalyses::none() : PreservedAnalyses::all();
	}