[llvm] r263982 - AMDGPU: Add SIWholeQuadMode pass
Nicolai Hähnle via llvm-commits
llvm-commits at lists.llvm.org
Mon Mar 21 15:39:00 PDT 2016
I'm looking into it now.
On 21.03.2016 17:26, Vitaly Buka wrote:
> Probably caused by this CL:
> http://lab.llvm.org:8011/builders/sanitizer-x86_64-linux-fast/builds/11271
>
> http://lab.llvm.org:8011/builders/sanitizer-x86_64-linux-fast/builds/11271/steps/check-llvm%20msan/logs/stdio
> http://lab.llvm.org:8011/builders/sanitizer-x86_64-linux-fast/builds/11271/steps/check-llvm%20asan/logs/stdio
>
> On Mon, Mar 21, 2016 at 1:33 PM Nicolai Haehnle via llvm-commits
> <llvm-commits at lists.llvm.org <mailto:llvm-commits at lists.llvm.org>> wrote:
>
> Author: nha
> Date: Mon Mar 21 15:28:33 2016
> New Revision: 263982
>
> URL: http://llvm.org/viewvc/llvm-project?rev=263982&view=rev
> Log:
> AMDGPU: Add SIWholeQuadMode pass
>
> Summary:
> Whole quad mode is already enabled for pixel shaders that compute
> derivatives, but it must be suspended for instructions that cause a
> shader to have side effects (i.e. stores and atomics).
>
> This pass addresses the issue by storing the real (initial) live mask
> in a register, masking EXEC before instructions that require exact
> execution and (re-)enabling WQM where required.
>
> This pass is run before register coalescing so that we can use
> machine SSA for analysis.
>
> The changes in this patch expose a problem with the second machine
> scheduling pass: target independent instructions like COPY implicitly
> use EXEC when they operate on VGPRs, but this fact is not encoded in
> the MIR. This can lead to miscompilation because instructions are
> moved past changes to EXEC.
>
> This patch fixes the problem by adding use-implicit operands to
> target independent instructions. Some general codegen passes are
> relaxed to work with such implicit use operands.
>
> Reviewers: arsenm, tstellarAMD, mareko
>
> Subscribers: MatzeB, arsenm, llvm-commits
>
> Differential Revision: http://reviews.llvm.org/D18162
>
> Added:
> llvm/trunk/lib/Target/AMDGPU/SIWholeQuadMode.cpp
> llvm/trunk/test/CodeGen/AMDGPU/wqm.ll
> Modified:
> llvm/trunk/lib/Target/AMDGPU/AMDGPU.h
> llvm/trunk/lib/Target/AMDGPU/AMDGPUInstrInfo.h
> llvm/trunk/lib/Target/AMDGPU/AMDGPUTargetMachine.cpp
> llvm/trunk/lib/Target/AMDGPU/CMakeLists.txt
> llvm/trunk/lib/Target/AMDGPU/SIInstrInfo.cpp
> llvm/trunk/lib/Target/AMDGPU/SIInstrInfo.h
> llvm/trunk/lib/Target/AMDGPU/SILowerControlFlow.cpp
> llvm/trunk/lib/Target/AMDGPU/SIRegisterInfo.h
>
> Modified: llvm/trunk/lib/Target/AMDGPU/AMDGPU.h
> URL:
> http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Target/AMDGPU/AMDGPU.h?rev=263982&r1=263981&r2=263982&view=diff
> ==============================================================================
> --- llvm/trunk/lib/Target/AMDGPU/AMDGPU.h (original)
> +++ llvm/trunk/lib/Target/AMDGPU/AMDGPU.h Mon Mar 21 15:28:33 2016
> @@ -44,6 +44,7 @@ FunctionPass *createSIFoldOperandsPass()
> FunctionPass *createSILowerI1CopiesPass();
> FunctionPass *createSIShrinkInstructionsPass();
> FunctionPass *createSILoadStoreOptimizerPass(TargetMachine &tm);
> +FunctionPass *createSIWholeQuadModePass();
> FunctionPass *createSILowerControlFlowPass();
> FunctionPass *createSIFixControlFlowLiveIntervalsPass();
> FunctionPass *createSIFixSGPRCopiesPass();
> @@ -70,6 +71,9 @@ extern char &SILowerI1CopiesID;
> void initializeSILoadStoreOptimizerPass(PassRegistry &);
> extern char &SILoadStoreOptimizerID;
>
> +void initializeSIWholeQuadModePass(PassRegistry &);
> +extern char &SIWholeQuadModeID;
> +
> void initializeSILowerControlFlowPass(PassRegistry &);
> extern char &SILowerControlFlowPassID;
>
>
> Modified: llvm/trunk/lib/Target/AMDGPU/AMDGPUInstrInfo.h
> URL:
> http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Target/AMDGPU/AMDGPUInstrInfo.h?rev=263982&r1=263981&r2=263982&view=diff
> ==============================================================================
> --- llvm/trunk/lib/Target/AMDGPU/AMDGPUInstrInfo.h (original)
> +++ llvm/trunk/lib/Target/AMDGPU/AMDGPUInstrInfo.h Mon Mar 21
> 15:28:33 2016
> @@ -62,7 +62,6 @@ public:
> int64_t Offset1, int64_t Offset2,
> unsigned NumLoads) const override;
>
> -
> /// \brief Return a target-specific opcode if Opcode is a pseudo
> instruction.
> /// Return -1 if the target-specific opcode for the pseudo
> instruction does
> /// not exist. If Opcode is not a pseudo instruction, this is
> identity.
>
> Modified: llvm/trunk/lib/Target/AMDGPU/AMDGPUTargetMachine.cpp
> URL:
> http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Target/AMDGPU/AMDGPUTargetMachine.cpp?rev=263982&r1=263981&r2=263982&view=diff
> ==============================================================================
> --- llvm/trunk/lib/Target/AMDGPU/AMDGPUTargetMachine.cpp (original)
> +++ llvm/trunk/lib/Target/AMDGPU/AMDGPUTargetMachine.cpp Mon Mar 21
> 15:28:33 2016
> @@ -57,6 +57,7 @@ extern "C" void LLVMInitializeAMDGPUTarg
> initializeSIAnnotateControlFlowPass(*PR);
> initializeSIInsertNopsPass(*PR);
> initializeSIInsertWaitsPass(*PR);
> + initializeSIWholeQuadModePass(*PR);
> initializeSILowerControlFlowPass(*PR);
> }
>
> @@ -346,6 +347,7 @@ void GCNPassConfig::addPreRegAlloc() {
> insertPass(&MachineSchedulerID, &RegisterCoalescerID);
> }
> addPass(createSIShrinkInstructionsPass(), false);
> + addPass(createSIWholeQuadModePass());
> }
>
> void GCNPassConfig::addFastRegAlloc(FunctionPass *RegAllocPass) {
>
> Modified: llvm/trunk/lib/Target/AMDGPU/CMakeLists.txt
> URL:
> http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Target/AMDGPU/CMakeLists.txt?rev=263982&r1=263981&r2=263982&view=diff
> ==============================================================================
> --- llvm/trunk/lib/Target/AMDGPU/CMakeLists.txt (original)
> +++ llvm/trunk/lib/Target/AMDGPU/CMakeLists.txt Mon Mar 21 15:28:33 2016
> @@ -63,6 +63,7 @@ add_llvm_target(AMDGPUCodeGen
> SIRegisterInfo.cpp
> SIShrinkInstructions.cpp
> SITypeRewriter.cpp
> + SIWholeQuadMode.cpp
> )
>
> add_subdirectory(AsmParser)
>
> Modified: llvm/trunk/lib/Target/AMDGPU/SIInstrInfo.cpp
> URL:
> http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Target/AMDGPU/SIInstrInfo.cpp?rev=263982&r1=263981&r2=263982&view=diff
> ==============================================================================
> --- llvm/trunk/lib/Target/AMDGPU/SIInstrInfo.cpp (original)
> +++ llvm/trunk/lib/Target/AMDGPU/SIInstrInfo.cpp Mon Mar 21 15:28:33
> 2016
> @@ -1248,6 +1248,19 @@ MachineInstr *SIInstrInfo::convertToThre
> .addImm(0); // omod
> }
>
> +bool SIInstrInfo::isSchedulingBoundary(const MachineInstr *MI,
> + const MachineBasicBlock *MBB,
> + const MachineFunction &MF)
> const {
> + // Target-independent instructions do not have an implicit-use of
> EXEC, even
> + // when they operate on VGPRs. Treating EXEC modifications as
> scheduling
> + // boundaries prevents incorrect movements of such instructions.
> + const TargetRegisterInfo *TRI = MF.getSubtarget().getRegisterInfo();
> + if (MI->modifiesRegister(AMDGPU::EXEC, TRI))
> + return true;
> +
> + return AMDGPUInstrInfo::isSchedulingBoundary(MI, MBB, MF);
> +}
> +
> bool SIInstrInfo::isInlineConstant(const APInt &Imm) const {
> int64_t SVal = Imm.getSExtValue();
> if (SVal >= -16 && SVal <= 64)
>
> Modified: llvm/trunk/lib/Target/AMDGPU/SIInstrInfo.h
> URL:
> http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Target/AMDGPU/SIInstrInfo.h?rev=263982&r1=263981&r2=263982&view=diff
> ==============================================================================
> --- llvm/trunk/lib/Target/AMDGPU/SIInstrInfo.h (original)
> +++ llvm/trunk/lib/Target/AMDGPU/SIInstrInfo.h Mon Mar 21 15:28:33 2016
> @@ -149,6 +149,10 @@ public:
> MachineBasicBlock::iterator &MI,
> LiveVariables *LV) const
> override;
>
> + bool isSchedulingBoundary(const MachineInstr *MI,
> + const MachineBasicBlock *MBB,
> + const MachineFunction &MF) const override;
> +
> static bool isSALU(const MachineInstr &MI) {
> return MI.getDesc().TSFlags & SIInstrFlags::SALU;
> }
>
> Modified: llvm/trunk/lib/Target/AMDGPU/SILowerControlFlow.cpp
> URL:
> http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Target/AMDGPU/SILowerControlFlow.cpp?rev=263982&r1=263981&r2=263982&view=diff
> ==============================================================================
> --- llvm/trunk/lib/Target/AMDGPU/SILowerControlFlow.cpp (original)
> +++ llvm/trunk/lib/Target/AMDGPU/SILowerControlFlow.cpp Mon Mar 21
> 15:28:33 2016
> @@ -78,7 +78,7 @@ private:
> void SkipIfDead(MachineInstr &MI);
>
> void If(MachineInstr &MI);
> - void Else(MachineInstr &MI);
> + void Else(MachineInstr &MI, bool ExecModified);
> void Break(MachineInstr &MI);
> void IfBreak(MachineInstr &MI);
> void ElseBreak(MachineInstr &MI);
> @@ -215,7 +215,7 @@ void SILowerControlFlow::If(MachineInstr
> MI.eraseFromParent();
> }
>
> -void SILowerControlFlow::Else(MachineInstr &MI) {
> +void SILowerControlFlow::Else(MachineInstr &MI, bool ExecModified) {
> MachineBasicBlock &MBB = *MI.getParent();
> DebugLoc DL = MI.getDebugLoc();
> unsigned Dst = MI.getOperand(0).getReg();
> @@ -225,6 +225,15 @@ void SILowerControlFlow::Else(MachineIns
> TII->get(AMDGPU::S_OR_SAVEEXEC_B64), Dst)
> .addReg(Src); // Saved EXEC
>
> + if (ExecModified) {
> + // Adjust the saved exec to account for the modifications
> during the flow
> + // block that contains the ELSE. This can happen when WQM mode
> is switched
> + // off.
> + BuildMI(MBB, &MI, DL, TII->get(AMDGPU::S_AND_B64), Dst)
> + .addReg(AMDGPU::EXEC)
> + .addReg(Dst);
> + }
> +
> BuildMI(MBB, &MI, DL, TII->get(AMDGPU::S_XOR_B64), AMDGPU::EXEC)
> .addReg(AMDGPU::EXEC)
> .addReg(Dst);
> @@ -488,7 +497,6 @@ bool SILowerControlFlow::runOnMachineFun
> SIMachineFunctionInfo *MFI = MF.getInfo<SIMachineFunctionInfo>();
>
> bool HaveKill = false;
> - bool NeedWQM = false;
> bool NeedFlat = false;
> unsigned Depth = 0;
>
> @@ -498,17 +506,24 @@ bool SILowerControlFlow::runOnMachineFun
> MachineBasicBlock *EmptyMBBAtEnd = NULL;
> MachineBasicBlock &MBB = *BI;
> MachineBasicBlock::iterator I, Next;
> + bool ExecModified = false;
> +
> for (I = MBB.begin(); I != MBB.end(); I = Next) {
> Next = std::next(I);
>
> MachineInstr &MI = *I;
> - if (TII->isWQM(MI) || TII->isDS(MI))
> - NeedWQM = true;
>
> // Flat uses m0 in case it needs to access LDS.
> if (TII->isFLAT(MI))
> NeedFlat = true;
>
> + for (const auto &Def : I->defs()) {
> + if (Def.isReg() && Def.isDef() && Def.getReg() ==
> AMDGPU::EXEC) {
> + ExecModified = true;
> + break;
> + }
> + }
> +
> switch (MI.getOpcode()) {
> default: break;
> case AMDGPU::SI_IF:
> @@ -517,7 +532,7 @@ bool SILowerControlFlow::runOnMachineFun
> break;
>
> case AMDGPU::SI_ELSE:
> - Else(MI);
> + Else(MI, ExecModified);
> break;
>
> case AMDGPU::SI_BREAK:
> @@ -599,12 +614,6 @@ bool SILowerControlFlow::runOnMachineFun
> }
> }
>
> - if (NeedWQM && MFI->getShaderType() == ShaderType::PIXEL) {
> - MachineBasicBlock &MBB = MF.front();
> - BuildMI(MBB, MBB.getFirstNonPHI(), DebugLoc(),
> TII->get(AMDGPU::S_WQM_B64),
> - AMDGPU::EXEC).addReg(AMDGPU::EXEC);
> - }
> -
> if (NeedFlat && MFI->IsKernel) {
> // TODO: What to use with function calls?
> // We will need to Initialize the flat scratch register pair.
>
> Modified: llvm/trunk/lib/Target/AMDGPU/SIRegisterInfo.h
> URL:
> http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Target/AMDGPU/SIRegisterInfo.h?rev=263982&r1=263981&r2=263982&view=diff
> ==============================================================================
> --- llvm/trunk/lib/Target/AMDGPU/SIRegisterInfo.h (original)
> +++ llvm/trunk/lib/Target/AMDGPU/SIRegisterInfo.h Mon Mar 21
> 15:28:33 2016
> @@ -72,9 +72,12 @@ public:
> }
>
> bool isSGPRReg(const MachineRegisterInfo &MRI, unsigned Reg) const {
> + const TargetRegisterClass *RC;
> if (TargetRegisterInfo::isVirtualRegister(Reg))
> - return isSGPRClass(MRI.getRegClass(Reg));
> - return getPhysRegClass(Reg);
> + RC = MRI.getRegClass(Reg);
> + else
> + RC = getPhysRegClass(Reg);
> + return isSGPRClass(RC);
> }
>
> /// \returns true if this class contains VGPR registers.
>
> Added: llvm/trunk/lib/Target/AMDGPU/SIWholeQuadMode.cpp
> URL:
> http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Target/AMDGPU/SIWholeQuadMode.cpp?rev=263982&view=auto
> ==============================================================================
> --- llvm/trunk/lib/Target/AMDGPU/SIWholeQuadMode.cpp (added)
> +++ llvm/trunk/lib/Target/AMDGPU/SIWholeQuadMode.cpp Mon Mar 21
> 15:28:33 2016
> @@ -0,0 +1,465 @@
> +//===-- SIWholeQuadMode.cpp - enter and suspend whole quad mode
> -----------===//
> +//
> +// The LLVM Compiler Infrastructure
> +//
> +// This file is distributed under the University of Illinois Open
> Source
> +// License. See LICENSE.TXT for details.
> +//
> +//===----------------------------------------------------------------------===//
> +//
> +/// \file
> +/// \brief This pass adds instructions to enable whole quad mode
> for pixel
> +/// shaders.
> +///
> +/// Whole quad mode is required for derivative computations, but it
> interferes
> +/// with shader side effects (stores and atomics). This pass is run
> on the
> +/// scheduled machine IR but before register coalescing, so that
> machine SSA is
> +/// available for analysis. It ensures that WQM is enabled when
> necessary, but
> +/// disabled around stores and atomics.
> +///
> +/// When necessary, this pass creates a function prolog
> +///
> +/// S_MOV_B64 LiveMask, EXEC
> +/// S_WQM_B64 EXEC, EXEC
> +///
> +/// to enter WQM at the top of the function and surrounds blocks of
> Exact
> +/// instructions by
> +///
> +/// S_AND_SAVEEXEC_B64 Tmp, LiveMask
> +/// ...
> +/// S_MOV_B64 EXEC, Tmp
> +///
> +/// In order to avoid excessive switching during sequences of Exact
> +/// instructions, the pass first analyzes which instructions must
> be run in WQM
> +/// (aka which instructions produce values that lead to derivative
> +/// computations).
> +///
> +/// Basic blocks are always exited in WQM as long as some successor
> needs WQM.
> +///
> +/// There is room for improvement given better control flow analysis:
> +///
> +/// (1) at the top level (outside of control flow statements, and
> as long as
> +/// kill hasn't been used), one SGPR can be saved by
> recovering WQM from
> +/// the LiveMask (this is implemented for the entry block).
> +///
> +/// (2) when entire regions (e.g. if-else blocks or entire loops) only
> +/// consist of exact and don't-care instructions, the switch
> only has to
> +/// be done at the entry and exit points rather than
> potentially in each
> +/// block of the region.
> +///
> +//===----------------------------------------------------------------------===//
> +
> +#include "AMDGPU.h"
> +#include "AMDGPUSubtarget.h"
> +#include "SIInstrInfo.h"
> +#include "SIMachineFunctionInfo.h"
> +#include "llvm/CodeGen/MachineDominanceFrontier.h"
> +#include "llvm/CodeGen/MachineDominators.h"
> +#include "llvm/CodeGen/MachineFunction.h"
> +#include "llvm/CodeGen/MachineFunctionPass.h"
> +#include "llvm/CodeGen/MachineInstrBuilder.h"
> +#include "llvm/CodeGen/MachineRegisterInfo.h"
> +#include "llvm/IR/Constants.h"
> +
> +using namespace llvm;
> +
> +#define DEBUG_TYPE "si-wqm"
> +
> +namespace {
> +
> +enum {
> + StateWQM = 0x1,
> + StateExact = 0x2,
> +};
> +
> +struct InstrInfo {
> + char Needs = 0;
> + char OutNeeds = 0;
> +};
> +
> +struct BlockInfo {
> + char Needs = 0;
> + char InNeeds = 0;
> + char OutNeeds = 0;
> +};
> +
> +struct WorkItem {
> + const MachineBasicBlock *MBB = nullptr;
> + const MachineInstr *MI = nullptr;
> +
> + WorkItem() {}
> + WorkItem(const MachineBasicBlock *MBB) : MBB(MBB) {}
> + WorkItem(const MachineInstr *MI) : MI(MI) {}
> +};
> +
> +class SIWholeQuadMode : public MachineFunctionPass {
> +private:
> + const SIInstrInfo *TII;
> + const SIRegisterInfo *TRI;
> + MachineRegisterInfo *MRI;
> +
> + DenseMap<const MachineInstr *, InstrInfo> Instructions;
> + DenseMap<const MachineBasicBlock *, BlockInfo> Blocks;
> + SmallVector<const MachineInstr *, 2> ExecExports;
> +
> + char scanInstructions(const MachineFunction &MF,
> std::vector<WorkItem>& Worklist);
> + void propagateInstruction(const MachineInstr &MI,
> std::vector<WorkItem>& Worklist);
> + void propagateBlock(const MachineBasicBlock &MBB,
> std::vector<WorkItem>& Worklist);
> + char analyzeFunction(const MachineFunction &MF);
> +
> + void toExact(MachineBasicBlock &MBB, MachineBasicBlock::iterator
> Before,
> + unsigned SaveWQM, unsigned LiveMaskReg);
> + void toWQM(MachineBasicBlock &MBB, MachineBasicBlock::iterator
> Before,
> + unsigned SavedWQM);
> + void processBlock(MachineBasicBlock &MBB, unsigned LiveMaskReg,
> bool isEntry);
> +
> +public:
> + static char ID;
> +
> + SIWholeQuadMode() :
> + MachineFunctionPass(ID) { }
> +
> + bool runOnMachineFunction(MachineFunction &MF) override;
> +
> + const char *getPassName() const override {
> + return "SI Whole Quad Mode";
> + }
> +
> + void getAnalysisUsage(AnalysisUsage &AU) const override {
> + AU.setPreservesCFG();
> + MachineFunctionPass::getAnalysisUsage(AU);
> + }
> +};
> +
> +} // End anonymous namespace
> +
> +char SIWholeQuadMode::ID = 0;
> +
> +INITIALIZE_PASS_BEGIN(SIWholeQuadMode, DEBUG_TYPE,
> + "SI Whole Quad Mode", false, false)
> +INITIALIZE_PASS_END(SIWholeQuadMode, DEBUG_TYPE,
> + "SI Whole Quad Mode", false, false)
> +
> +char &llvm::SIWholeQuadModeID = SIWholeQuadMode::ID;
> +
> +FunctionPass *llvm::createSIWholeQuadModePass() {
> + return new SIWholeQuadMode;
> +}
> +
> +// Scan instructions to determine which ones require an Exact
> execmask and
> +// which ones seed WQM requirements.
> +char SIWholeQuadMode::scanInstructions(const MachineFunction &MF,
> + std::vector<WorkItem>
> &Worklist) {
> + char GlobalFlags = 0;
> +
> + for (auto BI = MF.begin(), BE = MF.end(); BI != BE; ++BI) {
> + const MachineBasicBlock &MBB = *BI;
> +
> + for (auto II = MBB.begin(), IE = MBB.end(); II != IE; ++II) {
> + const MachineInstr &MI = *II;
> + unsigned Opcode = MI.getOpcode();
> + char Flags;
> +
> + if (TII->isWQM(Opcode) || TII->isDS(Opcode)) {
> + Flags = StateWQM;
> + } else if (TII->get(Opcode).mayStore() &&
> + (MI.getDesc().TSFlags & SIInstrFlags::VM_CNT)) {
> + Flags = StateExact;
> + } else {
> + // Handle export instructions with the exec mask valid flag set
> + if (Opcode == AMDGPU::EXP && MI.getOperand(4).getImm() != 0)
> + ExecExports.push_back(&MI);
> + continue;
> + }
> +
> + Instructions[&MI].Needs = Flags;
> + Worklist.push_back(&MI);
> + GlobalFlags |= Flags;
> + }
> + }
> +
> + return GlobalFlags;
> +}
> +
> +void SIWholeQuadMode::propagateInstruction(const MachineInstr &MI,
> + std::vector<WorkItem>&
> Worklist) {
> + const MachineBasicBlock &MBB = *MI.getParent();
> + InstrInfo &II = Instructions[&MI];
> + BlockInfo &BI = Blocks[&MBB];
> +
> + // Control flow-type instructions that are followed by WQM
> computations
> + // must themselves be in WQM.
> + if ((II.OutNeeds & StateWQM) && !(II.Needs & StateWQM) &&
> + (MI.isBranch() || MI.isTerminator() || MI.getOpcode() ==
> AMDGPU::SI_KILL))
> + II.Needs = StateWQM;
> +
> + // Propagate to block level
> + BI.Needs |= II.Needs;
> + if ((BI.InNeeds | II.Needs) != BI.InNeeds) {
> + BI.InNeeds |= II.Needs;
> + Worklist.push_back(&MBB);
> + }
> +
> + // Propagate backwards within block
> + if (const MachineInstr *PrevMI = MI.getPrevNode()) {
> + char InNeeds = II.Needs | II.OutNeeds;
> + if (!PrevMI->isPHI()) {
> + InstrInfo &PrevII = Instructions[PrevMI];
> + if ((PrevII.OutNeeds | InNeeds) != PrevII.OutNeeds) {
> + PrevII.OutNeeds |= InNeeds;
> + Worklist.push_back(PrevMI);
> + }
> + }
> + }
> +
> + // Propagate WQM flag to instruction inputs
> + assert(II.Needs != (StateWQM | StateExact));
> + if (II.Needs != StateWQM)
> + return;
> +
> + for (const MachineOperand &Use : MI.uses()) {
> + if (!Use.isReg() || !Use.isUse())
> + continue;
> +
> + // At this point, physical registers appear as inputs or outputs
> + // and following them makes no sense (and would in fact be
> incorrect
> + // when the same VGPR is used as both an output and an input
> that leads
> + // to a NeedsWQM instruction).
> + //
> + // Note: VCC appears e.g. in 64-bit addition with carry -
> theoretically we
> + // have to trace this, in practice it happens for 64-bit
> computations like
> + // pointers where both dwords are followed already anyway.
> + if (!TargetRegisterInfo::isVirtualRegister(Use.getReg()))
> + continue;
> +
> + for (const MachineOperand &Def : MRI->def_operands(Use.getReg())) {
> + const MachineInstr *DefMI = Def.getParent();
> + InstrInfo &DefII = Instructions[DefMI];
> +
> + // Obviously skip if DefMI is already flagged as NeedWQM.
> + //
> + // The instruction might also be flagged as NeedExact. This
> happens when
> + // the result of an atomic is used in a WQM computation. In
> this case,
> + // the atomic must not run for helper pixels and the WQM
> result is
> + // undefined.
> + if (DefII.Needs != 0)
> + continue;
> +
> + DefII.Needs = StateWQM;
> + Worklist.push_back(DefMI);
> + }
> + }
> +}
> +
> +void SIWholeQuadMode::propagateBlock(const MachineBasicBlock &MBB,
> + std::vector<WorkItem>& Worklist) {
> + BlockInfo &BI = Blocks[&MBB];
> +
> + // Propagate through instructions
> + if (!MBB.empty()) {
> + const MachineInstr *LastMI = &*MBB.rbegin();
> + InstrInfo &LastII = Instructions[LastMI];
> + if ((LastII.OutNeeds | BI.OutNeeds) != LastII.OutNeeds) {
> + LastII.OutNeeds |= BI.OutNeeds;
> + Worklist.push_back(LastMI);
> + }
> + }
> +
> + // Predecessor blocks must provide for our WQM/Exact needs.
> + for (const MachineBasicBlock *Pred : MBB.predecessors()) {
> + BlockInfo &PredBI = Blocks[Pred];
> + if ((PredBI.OutNeeds | BI.InNeeds) == PredBI.OutNeeds)
> + continue;
> +
> + PredBI.OutNeeds |= BI.InNeeds;
> + PredBI.InNeeds |= BI.InNeeds;
> + Worklist.push_back(Pred);
> + }
> +
> + // All successors must be prepared to accept the same set of
> WQM/Exact
> + // data.
> + for (const MachineBasicBlock *Succ : MBB.successors()) {
> + BlockInfo &SuccBI = Blocks[Succ];
> + if ((SuccBI.InNeeds | BI.OutNeeds) == SuccBI.InNeeds)
> + continue;
> +
> + SuccBI.InNeeds |= BI.OutNeeds;
> + Worklist.push_back(Succ);
> + }
> +}
> +
> +char SIWholeQuadMode::analyzeFunction(const MachineFunction &MF) {
> + std::vector<WorkItem> Worklist;
> + char GlobalFlags = scanInstructions(MF, Worklist);
> +
> + while (!Worklist.empty()) {
> + WorkItem WI = Worklist.back();
> + Worklist.pop_back();
> +
> + if (WI.MI)
> + propagateInstruction(*WI.MI, Worklist);
> + else
> + propagateBlock(*WI.MBB, Worklist);
> + }
> +
> + return GlobalFlags;
> +}
> +
> +void SIWholeQuadMode::toExact(MachineBasicBlock &MBB,
> + MachineBasicBlock::iterator Before,
> + unsigned SaveWQM, unsigned LiveMaskReg)
> +{
> + if (SaveWQM) {
> + BuildMI(MBB, Before, DebugLoc(),
> TII->get(AMDGPU::S_AND_SAVEEXEC_B64),
> + SaveWQM)
> + .addReg(LiveMaskReg);
> + } else {
> + BuildMI(MBB, Before, DebugLoc(), TII->get(AMDGPU::S_AND_B64),
> + AMDGPU::EXEC)
> + .addReg(AMDGPU::EXEC)
> + .addReg(LiveMaskReg);
> + }
> +}
> +
> +void SIWholeQuadMode::toWQM(MachineBasicBlock &MBB,
> + MachineBasicBlock::iterator Before,
> + unsigned SavedWQM)
> +{
> + if (SavedWQM) {
> + BuildMI(MBB, Before, DebugLoc(), TII->get(AMDGPU::COPY),
> AMDGPU::EXEC)
> + .addReg(SavedWQM);
> + } else {
> + BuildMI(MBB, Before, DebugLoc(), TII->get(AMDGPU::S_WQM_B64),
> + AMDGPU::EXEC)
> + .addReg(AMDGPU::EXEC);
> + }
> +}
> +
> +void SIWholeQuadMode::processBlock(MachineBasicBlock &MBB, unsigned
> LiveMaskReg,
> + bool isEntry) {
> + auto BII = Blocks.find(&MBB);
> + if (BII == Blocks.end())
> + return;
> +
> + const BlockInfo &BI = BII->second;
> +
> + if (!(BI.InNeeds & StateWQM))
> + return;
> +
> + // This is a non-entry block that is WQM throughout, so no need to do
> + // anything.
> + if (!isEntry && !(BI.Needs & StateExact) && BI.OutNeeds !=
> StateExact)
> + return;
> +
> + unsigned SavedWQMReg = 0;
> + bool WQMFromExec = isEntry;
> + char State = isEntry ? StateExact : StateWQM;
> +
> + auto II = MBB.getFirstNonPHI(), IE = MBB.end();
> + while (II != IE) {
> + MachineInstr &MI = *II;
> + ++II;
> +
> + // Skip instructions that are not affected by EXEC
> + if (MI.getDesc().TSFlags & (SIInstrFlags::SALU |
> SIInstrFlags::SMRD) &&
> + !MI.isBranch() && !MI.isTerminator())
> + continue;
> +
> + // Generic instructions such as COPY will either disappear by
> register
> + // coalescing or be lowered to SALU or VALU instructions.
> + if (TargetInstrInfo::isGenericOpcode(MI.getOpcode())) {
> + if (MI.getNumExplicitOperands() >= 1) {
> + const MachineOperand &Op = MI.getOperand(0);
> + if (Op.isReg()) {
> + if (TRI->isSGPRReg(*MRI, Op.getReg())) {
> + // SGPR instructions are not affected by EXEC
> + continue;
> + }
> + }
> + }
> + }
> +
> + char Needs = 0;
> + char OutNeeds = 0;
> + auto InstrInfoIt = Instructions.find(&MI);
> + if (InstrInfoIt != Instructions.end()) {
> + Needs = InstrInfoIt->second.Needs;
> + OutNeeds = InstrInfoIt->second.OutNeeds;
> +
> + // Make sure to switch to Exact mode before the end of the
> block when
> + // Exact and only Exact is needed further downstream.
> + if (OutNeeds == StateExact && (MI.isBranch() ||
> MI.isTerminator())) {
> + assert(Needs == 0);
> + Needs = StateExact;
> + }
> + }
> +
> + // State switching
> + if (Needs && State != Needs) {
> + if (Needs == StateExact) {
> + assert(!SavedWQMReg);
> +
> + if (!WQMFromExec && (OutNeeds & StateWQM))
> + SavedWQMReg =
> MRI->createVirtualRegister(&AMDGPU::SReg_64RegClass);
> +
> + toExact(MBB, &MI, SavedWQMReg, LiveMaskReg);
> + } else {
> + assert(WQMFromExec == (SavedWQMReg == 0));
> + toWQM(MBB, &MI, SavedWQMReg);
> + SavedWQMReg = 0;
> + }
> +
> + State = Needs;
> + }
> +
> + if (MI.getOpcode() == AMDGPU::SI_KILL)
> + WQMFromExec = false;
> + }
> +
> + if ((BI.OutNeeds & StateWQM) && State != StateWQM) {
> + assert(WQMFromExec == (SavedWQMReg == 0));
> + toWQM(MBB, MBB.end(), SavedWQMReg);
> + } else if (BI.OutNeeds == StateExact && State != StateExact) {
> + toExact(MBB, MBB.end(), 0, LiveMaskReg);
> + }
> +}
> +
> +bool SIWholeQuadMode::runOnMachineFunction(MachineFunction &MF) {
> + SIMachineFunctionInfo *MFI = MF.getInfo<SIMachineFunctionInfo>();
> +
> + if (MFI->getShaderType() != ShaderType::PIXEL)
> + return false;
> +
> + Instructions.clear();
> + Blocks.clear();
> + ExecExports.clear();
> +
> + TII = static_cast<const SIInstrInfo
> *>(MF.getSubtarget().getInstrInfo());
> + TRI = static_cast<const SIRegisterInfo
> *>(MF.getSubtarget().getRegisterInfo());
> + MRI = &MF.getRegInfo();
> +
> + char GlobalFlags = analyzeFunction(MF);
> + if (!(GlobalFlags & StateWQM))
> + return false;
> +
> + MachineBasicBlock &Entry = MF.front();
> + MachineInstr *EntryMI = Entry.getFirstNonPHI();
> +
> + if (GlobalFlags == StateWQM) {
> + // For a shader that needs only WQM, we can just set it once.
> + BuildMI(Entry, EntryMI, DebugLoc(), TII->get(AMDGPU::S_WQM_B64),
> + AMDGPU::EXEC).addReg(AMDGPU::EXEC);
> + return true;
> + }
> +
> + // Handle the general case
> + unsigned LiveMaskReg =
> MRI->createVirtualRegister(&AMDGPU::SReg_64RegClass);
> + BuildMI(Entry, EntryMI, DebugLoc(), TII->get(AMDGPU::COPY),
> LiveMaskReg)
> + .addReg(AMDGPU::EXEC);
> +
> + for (const auto &BII : Blocks)
> + processBlock(const_cast<MachineBasicBlock &>(*BII.first),
> LiveMaskReg,
> + BII.first == &*MF.begin());
> +
> + return true;
> +}
>
> Added: llvm/trunk/test/CodeGen/AMDGPU/wqm.ll
> URL:
> http://llvm.org/viewvc/llvm-project/llvm/trunk/test/CodeGen/AMDGPU/wqm.ll?rev=263982&view=auto
> ==============================================================================
> --- llvm/trunk/test/CodeGen/AMDGPU/wqm.ll (added)
> +++ llvm/trunk/test/CodeGen/AMDGPU/wqm.ll Mon Mar 21 15:28:33 2016
> @@ -0,0 +1,348 @@
> +;RUN: llc < %s -march=amdgcn -mcpu=verde -verify-machineinstrs |
> FileCheck %s --check-prefix=CHECK --check-prefix=SI
> +;RUN: llc < %s -march=amdgcn -mcpu=tonga -verify-machineinstrs |
> FileCheck %s --check-prefix=CHECK --check-prefix=VI
> +
> +; Check that WQM isn't triggered by image load/store intrinsics.
> +;
> +;CHECK-LABEL: {{^}}test1:
> +;CHECK-NOT: s_wqm
> +define <4 x float> @test1(<8 x i32> inreg %rsrc, <4 x i32> %c) #0 {
> +main_body:
> + %tex = call <4 x float> @llvm.amdgcn.image.load.v4i32(<4 x i32>
> %c, <8 x i32> %rsrc, i32 15, i1 0, i1 0, i1 0, i1 0)
> + call void @llvm.amdgcn.image.store.v4i32(<4 x float> %tex, <4 x
> i32> %c, <8 x i32> %rsrc, i32 15, i1 0, i1 0, i1 0, i1 0)
> + ret <4 x float> %tex
> +}
> +
> +; Check that WQM is triggered by image samples and left untouched
> for loads...
> +;
> +;CHECK-LABEL: {{^}}test2:
> +;CHECK-NEXT: ; %main_body
> +;CHECK-NEXT: s_wqm_b64 exec, exec
> +;CHECK: image_sample
> +;CHECK-NOT: exec
> +;CHECK: _load_dword v0,
> +define float @test2(<8 x i32> inreg %rsrc, <4 x i32> inreg
> %sampler, float addrspace(1)* inreg %ptr, <4 x i32> %c) #0 {
> +main_body:
> + %c.1 = call <4 x float> @llvm.SI.image.sample.v4i32(<4 x i32> %c,
> <8 x i32> %rsrc, <4 x i32> %sampler, i32 15, i32 0, i32 0, i32 0,
> i32 0, i32 0, i32 0, i32 0)
> + %c.2 = bitcast <4 x float> %c.1 to <4 x i32>
> + %c.3 = extractelement <4 x i32> %c.2, i32 0
> + %gep = getelementptr float, float addrspace(1)* %ptr, i32 %c.3
> + %data = load float, float addrspace(1)* %gep
> + ret float %data
> +}
> +
> +; ... but disabled for stores (and, in this simple case, not
> re-enabled).
> +;
> +;CHECK-LABEL: {{^}}test3:
> +;CHECK-NEXT: ; %main_body
> +;CHECK-NEXT: s_mov_b64 [[ORIG:s\[[0-9]+:[0-9]+\]]], exec
> +;CHECK-NEXT: s_wqm_b64 exec, exec
> +;CHECK: image_sample
> +;CHECK: s_and_b64 exec, exec, [[ORIG]]
> +;CHECK: store
> +;CHECK-NOT: exec
> +define <4 x float> @test3(<8 x i32> inreg %rsrc, <4 x i32> inreg
> %sampler, float addrspace(1)* inreg %ptr, <4 x i32> %c) #0 {
> +main_body:
> + %tex = call <4 x float> @llvm.SI.image.sample.v4i32(<4 x i32> %c,
> <8 x i32> %rsrc, <4 x i32> %sampler, i32 15, i32 0, i32 0, i32 0,
> i32 0, i32 0, i32 0, i32 0)
> + %tex.1 = bitcast <4 x float> %tex to <4 x i32>
> + %tex.2 = extractelement <4 x i32> %tex.1, i32 0
> + %gep = getelementptr float, float addrspace(1)* %ptr, i32 %tex.2
> + %wr = extractelement <4 x float> %tex, i32 1
> + store float %wr, float addrspace(1)* %gep
> + ret <4 x float> %tex
> +}
> +
> +; Check that WQM is re-enabled when required.
> +;
> +;CHECK-LABEL: {{^}}test4:
> +;CHECK-NEXT: ; %main_body
> +;CHECK-NEXT: s_mov_b64 [[ORIG:s\[[0-9]+:[0-9]+\]]], exec
> +;CHECK-NEXT: s_wqm_b64 exec, exec
> +;CHECK: v_mul_lo_i32 [[MUL:v[0-9]+]], v0, v1
> +;CHECK: s_and_b64 exec, exec, [[ORIG]]
> +;CHECK: store
> +;CHECK: s_wqm_b64 exec, exec
> +;CHECK: image_sample v[0:3], [[MUL]], s[0:7], s[8:11] dmask:0xf
> +define <4 x float> @test4(<8 x i32> inreg %rsrc, <4 x i32> inreg
> %sampler, float addrspace(1)* inreg %ptr, i32 %c, i32 %d, float
> %data) #0 {
> +main_body:
> + %c.1 = mul i32 %c, %d
> + %gep = getelementptr float, float addrspace(1)* %ptr, i32 %c.1
> + store float %data, float addrspace(1)* %gep
> + %tex = call <4 x float> @llvm.SI.image.sample.i32(i32 %c.1, <8 x
> i32> %rsrc, <4 x i32> %sampler, i32 15, i32 0, i32 0, i32 0, i32 0,
> i32 0, i32 0, i32 0)
> + ret <4 x float> %tex
> +}
> +
> +; Check a case of one branch of an if-else requiring WQM, the other
> requiring
> +; exact.
> +;
> +; Note: In this particular case, the save-and-restore could be
> avoided if the
> +; analysis understood that the two branches of the if-else are mutually
> +; exclusive.
> +;
> +;CHECK-LABEL: {{^}}test_control_flow_0:
> +;CHECK-NEXT: ; %main_body
> +;CHECK-NEXT: s_mov_b64 [[ORIG:s\[[0-9]+:[0-9]+\]]], exec
> +;CHECK-NEXT: s_wqm_b64 exec, exec
> +;CHECK: %ELSE
> +;CHECK: s_and_saveexec_b64 [[SAVED:s\[[0-9]+:[0-9]+\]]], [[ORIG]]
> +;CHECK: store
> +;CHECK: s_mov_b64 exec, [[SAVED]]
> +;CHECK: %IF
> +;CHECK: image_sample
> +define float @test_control_flow_0(<8 x i32> inreg %rsrc, <4 x i32>
> inreg %sampler, float addrspace(1)* inreg %ptr, i32 %c, i32 %z,
> float %data) #0 {
> +main_body:
> + %cmp = icmp eq i32 %z, 0
> + br i1 %cmp, label %IF, label %ELSE
> +
> +IF:
> + %tex = call <4 x float> @llvm.SI.image.sample.i32(i32 %c, <8 x
> i32> %rsrc, <4 x i32> %sampler, i32 15, i32 0, i32 0, i32 0, i32 0,
> i32 0, i32 0, i32 0)
> + %data.if = extractelement <4 x float> %tex, i32 0
> + br label %END
> +
> +ELSE:
> + %gep = getelementptr float, float addrspace(1)* %ptr, i32 %c
> + store float %data, float addrspace(1)* %gep
> + br label %END
> +
> +END:
> + %r = phi float [ %data.if, %IF ], [ %data, %ELSE ]
> + ret float %r
> +}
> +
> +; Reverse branch order compared to the previous test.
> +;
> +;CHECK-LABEL: {{^}}test_control_flow_1:
> +;CHECK-NEXT: ; %main_body
> +;CHECK-NEXT: s_mov_b64 [[ORIG:s\[[0-9]+:[0-9]+\]]], exec
> +;CHECK-NEXT: s_wqm_b64 exec, exec
> +;CHECK: %IF
> +;CHECK: image_sample
> +;CHECK: %Flow
> +;CHECK-NEXT: s_or_saveexec_b64 [[SAVED:s\[[0-9]+:[0-9]+\]]],
> +;CHECK-NEXT: s_and_b64 exec, exec, [[ORIG]]
> +;CHECK-NEXT: s_and_b64 [[SAVED]], exec, [[SAVED]]
> +;CHECK-NEXT: s_xor_b64 exec, exec, [[SAVED]]
> +;CHECK-NEXT: %ELSE
> +;CHECK: store
> +;CHECK: %END
> +define float @test_control_flow_1(<8 x i32> inreg %rsrc, <4 x i32>
> inreg %sampler, float addrspace(1)* inreg %ptr, i32 %c, i32 %z,
> float %data) #0 {
> +main_body:
> + %cmp = icmp eq i32 %z, 0
> + br i1 %cmp, label %ELSE, label %IF
> +
> +IF:
> + %tex = call <4 x float> @llvm.SI.image.sample.i32(i32 %c, <8 x
> i32> %rsrc, <4 x i32> %sampler, i32 15, i32 0, i32 0, i32 0, i32 0,
> i32 0, i32 0, i32 0)
> + %data.if = extractelement <4 x float> %tex, i32 0
> + br label %END
> +
> +ELSE:
> + %gep = getelementptr float, float addrspace(1)* %ptr, i32 %c
> + store float %data, float addrspace(1)* %gep
> + br label %END
> +
> +END:
> + %r = phi float [ %data.if, %IF ], [ %data, %ELSE ]
> + ret float %r
> +}
> +
> +; Check that branch conditions are properly marked as needing WQM...
> +;
> +;CHECK-LABEL: {{^}}test_control_flow_2:
> +;CHECK-NEXT: ; %main_body
> +;CHECK-NEXT: s_mov_b64 [[ORIG:s\[[0-9]+:[0-9]+\]]], exec
> +;CHECK-NEXT: s_wqm_b64 exec, exec
> +;CHECK: s_and_b64 exec, exec, [[ORIG]]
> +;CHECK: store
> +;CHECK: s_wqm_b64 exec, exec
> +;CHECK: load
> +;CHECK: s_and_b64 exec, exec, [[ORIG]]
> +;CHECK: store
> +;CHECK: s_wqm_b64 exec, exec
> +;CHECK: v_cmp
> +define <4 x float> @test_control_flow_2(<8 x i32> inreg %rsrc, <4 x
> i32> inreg %sampler, float addrspace(1)* inreg %ptr, <3 x i32> %idx,
> <2 x float> %data, i32 %coord) #0 {
> +main_body:
> + %idx.1 = extractelement <3 x i32> %idx, i32 0
> + %gep.1 = getelementptr float, float addrspace(1)* %ptr, i32 %idx.1
> + %data.1 = extractelement <2 x float> %data, i32 0
> + store float %data.1, float addrspace(1)* %gep.1
> +
> + ; The load that determines the branch (and should therefore be
> WQM) is
> + ; surrounded by stores that require disabled WQM.
> + %idx.2 = extractelement <3 x i32> %idx, i32 1
> + %gep.2 = getelementptr float, float addrspace(1)* %ptr, i32 %idx.2
> + %z = load float, float addrspace(1)* %gep.2
> +
> + %idx.3 = extractelement <3 x i32> %idx, i32 2
> + %gep.3 = getelementptr float, float addrspace(1)* %ptr, i32 %idx.3
> + %data.3 = extractelement <2 x float> %data, i32 1
> + store float %data.3, float addrspace(1)* %gep.3
> +
> + %cc = fcmp ogt float %z, 0.0
> + br i1 %cc, label %IF, label %ELSE
> +
> +IF:
> + %coord.IF = mul i32 %coord, 3
> + br label %END
> +
> +ELSE:
> + %coord.ELSE = mul i32 %coord, 4
> + br label %END
> +
> +END:
> + %coord.END = phi i32 [ %coord.IF, %IF ], [ %coord.ELSE, %ELSE ]
> + %tex = call <4 x float> @llvm.SI.image.sample.i32(i32 %coord.END,
> <8 x i32> %rsrc, <4 x i32> %sampler, i32 15, i32 0, i32 0, i32 0,
> i32 0, i32 0, i32 0, i32 0)
> + ret <4 x float> %tex
> +}
> +
> +; ... but only if they really do need it.
> +;
> +;CHECK-LABEL: {{^}}test_control_flow_3:
> +;CHECK-NEXT: ; %main_body
> +;CHECK-NEXT: s_mov_b64 [[ORIG:s\[[0-9]+:[0-9]+\]]], exec
> +;CHECK-NEXT: s_wqm_b64 exec, exec
> +;CHECK: image_sample
> +;CHECK: s_and_b64 exec, exec, [[ORIG]]
> +;CHECK: store
> +;CHECK: load
> +;CHECK: store
> +;CHECK: v_cmp
> +define float @test_control_flow_3(<8 x i32> inreg %rsrc, <4 x i32>
> inreg %sampler, float addrspace(1)* inreg %ptr, <3 x i32> %idx, <2 x
> float> %data, i32 %coord) #0 {
> +main_body:
> + %tex = call <4 x float> @llvm.SI.image.sample.i32(i32 %coord, <8
> x i32> %rsrc, <4 x i32> %sampler, i32 15, i32 0, i32 0, i32 0, i32
> 0, i32 0, i32 0, i32 0)
> + %tex.1 = extractelement <4 x float> %tex, i32 0
> +
> + %idx.1 = extractelement <3 x i32> %idx, i32 0
> + %gep.1 = getelementptr float, float addrspace(1)* %ptr, i32 %idx.1
> + %data.1 = extractelement <2 x float> %data, i32 0
> + store float %data.1, float addrspace(1)* %gep.1
> +
> + %idx.2 = extractelement <3 x i32> %idx, i32 1
> + %gep.2 = getelementptr float, float addrspace(1)* %ptr, i32 %idx.2
> + %z = load float, float addrspace(1)* %gep.2
> +
> + %idx.3 = extractelement <3 x i32> %idx, i32 2
> + %gep.3 = getelementptr float, float addrspace(1)* %ptr, i32 %idx.3
> + %data.3 = extractelement <2 x float> %data, i32 1
> + store float %data.3, float addrspace(1)* %gep.3
> +
> + %cc = fcmp ogt float %z, 0.0
> + br i1 %cc, label %IF, label %ELSE
> +
> +IF:
> + %tex.IF = fmul float %tex.1, 3.0
> + br label %END
> +
> +ELSE:
> + %tex.ELSE = fmul float %tex.1, 4.0
> + br label %END
> +
> +END:
> + %tex.END = phi float [ %tex.IF, %IF ], [ %tex.ELSE, %ELSE ]
> + ret float %tex.END
> +}
> +
> +; Another test that failed at some point because of terminator
> handling.
> +;
> +;CHECK-LABEL: {{^}}test_control_flow_4:
> +;CHECK-NEXT: ; %main_body
> +;CHECK-NEXT: s_mov_b64 [[ORIG:s\[[0-9]+:[0-9]+\]]], exec
> +;CHECK-NEXT: s_wqm_b64 exec, exec
> +;CHECK: %IF
> +;CHECK: load
> +;CHECK: s_and_saveexec_b64 [[SAVE:s\[[0-9]+:[0-9]+\]]], [[ORIG]]
> +;CHECK: store
> +;CHECK: s_mov_b64 exec, [[SAVE]]
> +;CHECK: %END
> +;CHECK: image_sample
> +define <4 x float> @test_control_flow_4(<8 x i32> inreg %rsrc, <4 x
> i32> inreg %sampler, float addrspace(1)* inreg %ptr, i32 %coord, i32
> %y, float %z) #0 {
> +main_body:
> + %cond = icmp eq i32 %y, 0
> + br i1 %cond, label %IF, label %END
> +
> +IF:
> + %data = load float, float addrspace(1)* %ptr
> + %gep = getelementptr float, float addrspace(1)* %ptr, i32 1
> + store float %data, float addrspace(1)* %gep
> + br label %END
> +
> +END:
> + %tex = call <4 x float> @llvm.SI.image.sample.i32(i32 %coord, <8
> x i32> %rsrc, <4 x i32> %sampler, i32 15, i32 0, i32 0, i32 0, i32
> 0, i32 0, i32 0, i32 0)
> + ret <4 x float> %tex
> +}
> +
> +; Kill is performed in WQM mode so that uniform kill behaves
> correctly ...
> +;
> +;CHECK-LABEL: {{^}}test_kill_0:
> +;CHECK-NEXT: ; %main_body
> +;CHECK-NEXT: s_mov_b64 [[ORIG:s\[[0-9]+:[0-9]+\]]], exec
> +;CHECK-NEXT: s_wqm_b64 exec, exec
> +;CHECK: image_sample
> +;CHECK: s_and_b64 exec, exec, [[ORIG]]
> +;SI: buffer_store_dword
> +;VI: flat_store_dword
> +;CHECK: s_wqm_b64 exec, exec
> +;CHECK: v_cmpx_
> +;CHECK: s_and_saveexec_b64 [[SAVE:s\[[0-9]+:[0-9]+\]]], [[ORIG]]
> +;SI: buffer_store_dword
> +;VI: flat_store_dword
> +;CHECK: s_mov_b64 exec, [[SAVE]]
> +;CHECK: image_sample
> +define <4 x float> @test_kill_0(<8 x i32> inreg %rsrc, <4 x i32>
> inreg %sampler, float addrspace(1)* inreg %ptr, <2 x i32> %idx, <2 x
> float> %data, i32 %coord, i32 %coord2, float %z) #0 {
> +main_body:
> + %tex = call <4 x float> @llvm.SI.image.sample.i32(i32 %coord, <8
> x i32> %rsrc, <4 x i32> %sampler, i32 15, i32 0, i32 0, i32 0, i32
> 0, i32 0, i32 0, i32 0)
> +
> + %idx.0 = extractelement <2 x i32> %idx, i32 0
> + %gep.0 = getelementptr float, float addrspace(1)* %ptr, i32 %idx.0
> + %data.0 = extractelement <2 x float> %data, i32 0
> + store float %data.0, float addrspace(1)* %gep.0
> +
> + call void @llvm.AMDGPU.kill(float %z)
> +
> + %idx.1 = extractelement <2 x i32> %idx, i32 1
> + %gep.1 = getelementptr float, float addrspace(1)* %ptr, i32 %idx.1
> + %data.1 = extractelement <2 x float> %data, i32 1
> + store float %data.1, float addrspace(1)* %gep.1
> +
> + %tex2 = call <4 x float> @llvm.SI.image.sample.i32(i32 %coord2,
> <8 x i32> %rsrc, <4 x i32> %sampler, i32 15, i32 0, i32 0, i32 0,
> i32 0, i32 0, i32 0, i32 0)
> + %out = fadd <4 x float> %tex, %tex2
> +
> + ret <4 x float> %out
> +}
> +
> +; ... but only if WQM is necessary.
> +;
> +;CHECK-LABEL: {{^}}test_kill_1:
> +;CHECK-NEXT: ; %main_body
> +;CHECK-NEXT: s_mov_b64 [[ORIG:s\[[0-9]+:[0-9]+\]]], exec
> +;CHECK-NEXT: s_wqm_b64 exec, exec
> +;CHECK: image_sample
> +;CHECK: s_and_b64 exec, exec, [[ORIG]]
> +;SI: buffer_store_dword
> +;VI: flat_store_dword
> +;CHECK-NOT: wqm
> +;CHECK: v_cmpx_
> +define <4 x float> @test_kill_1(<8 x i32> inreg %rsrc, <4 x i32>
> inreg %sampler, float addrspace(1)* inreg %ptr, i32 %idx, float
> %data, i32 %coord, i32 %coord2, float %z) #0 {
> +main_body:
> + %tex = call <4 x float> @llvm.SI.image.sample.i32(i32 %coord, <8
> x i32> %rsrc, <4 x i32> %sampler, i32 15, i32 0, i32 0, i32 0, i32
> 0, i32 0, i32 0, i32 0)
> +
> + %gep = getelementptr float, float addrspace(1)* %ptr, i32 %idx
> + store float %data, float addrspace(1)* %gep
> +
> + call void @llvm.AMDGPU.kill(float %z)
> +
> + ret <4 x float> %tex
> +}
> +
> +declare void @llvm.amdgcn.image.store.v4i32(<4 x float>, <4 x i32>,
> <8 x i32>, i32, i1, i1, i1, i1) #1
> +
> +declare <4 x float> @llvm.amdgcn.image.load.v4i32(<4 x i32>, <8 x
> i32>, i32, i1, i1, i1, i1) #2
> +
> +declare <4 x float> @llvm.SI.image.sample.i32(i32, <8 x i32>, <4 x
> i32>, i32, i32, i32, i32, i32, i32, i32, i32) #3
> +declare <4 x float> @llvm.SI.image.sample.v4i32(<4 x i32>, <8 x
> i32>, <4 x i32>, i32, i32, i32, i32, i32, i32, i32, i32) #3
> +
> +declare void @llvm.AMDGPU.kill(float)
> +declare void @llvm.SI.export(i32, i32, i32, i32, i32, float, float,
> float, float)
> +
> +attributes #0 = { "ShaderType"="0" }
> +attributes #1 = { nounwind }
> +attributes #2 = { nounwind readonly }
> +attributes #3 = { nounwind readnone }
>
>
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