1683 lines
60 KiB
C++
1683 lines
60 KiB
C++
//===- SIInsertWaitcnts.cpp - Insert Wait Instructions --------------------===//
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//
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// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
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// See https://llvm.org/LICENSE.txt for license information.
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// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
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//
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//===----------------------------------------------------------------------===//
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//
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/// \file
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/// Insert wait instructions for memory reads and writes.
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///
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/// Memory reads and writes are issued asynchronously, so we need to insert
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/// S_WAITCNT instructions when we want to access any of their results or
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/// overwrite any register that's used asynchronously.
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///
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/// TODO: This pass currently keeps one timeline per hardware counter. A more
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/// finely-grained approach that keeps one timeline per event type could
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/// sometimes get away with generating weaker s_waitcnt instructions. For
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/// example, when both SMEM and LDS are in flight and we need to wait for
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/// the i-th-last LDS instruction, then an lgkmcnt(i) is actually sufficient,
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/// but the pass will currently generate a conservative lgkmcnt(0) because
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/// multiple event types are in flight.
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//
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//===----------------------------------------------------------------------===//
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#include "AMDGPU.h"
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#include "GCNSubtarget.h"
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#include "MCTargetDesc/AMDGPUMCTargetDesc.h"
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#include "SIMachineFunctionInfo.h"
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#include "llvm/ADT/MapVector.h"
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#include "llvm/ADT/PostOrderIterator.h"
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#include "llvm/CodeGen/MachinePostDominators.h"
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#include "llvm/InitializePasses.h"
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#include "llvm/Support/DebugCounter.h"
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#include "llvm/Support/TargetParser.h"
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using namespace llvm;
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#define DEBUG_TYPE "si-insert-waitcnts"
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DEBUG_COUNTER(ForceExpCounter, DEBUG_TYPE"-forceexp",
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"Force emit s_waitcnt expcnt(0) instrs");
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DEBUG_COUNTER(ForceLgkmCounter, DEBUG_TYPE"-forcelgkm",
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"Force emit s_waitcnt lgkmcnt(0) instrs");
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DEBUG_COUNTER(ForceVMCounter, DEBUG_TYPE"-forcevm",
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"Force emit s_waitcnt vmcnt(0) instrs");
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static cl::opt<bool> ForceEmitZeroFlag(
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"amdgpu-waitcnt-forcezero",
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cl::desc("Force all waitcnt instrs to be emitted as s_waitcnt vmcnt(0) expcnt(0) lgkmcnt(0)"),
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cl::init(false), cl::Hidden);
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namespace {
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template <typename EnumT>
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class enum_iterator
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: public iterator_facade_base<enum_iterator<EnumT>,
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std::forward_iterator_tag, const EnumT> {
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EnumT Value;
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public:
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enum_iterator() = default;
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enum_iterator(EnumT Value) : Value(Value) {}
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enum_iterator &operator++() {
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Value = static_cast<EnumT>(Value + 1);
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return *this;
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}
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bool operator==(const enum_iterator &RHS) const { return Value == RHS.Value; }
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EnumT operator*() const { return Value; }
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};
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// Class of object that encapsulates latest instruction counter score
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// associated with the operand. Used for determining whether
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// s_waitcnt instruction needs to be emited.
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#define CNT_MASK(t) (1u << (t))
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enum InstCounterType { VM_CNT = 0, LGKM_CNT, EXP_CNT, VS_CNT, NUM_INST_CNTS };
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iterator_range<enum_iterator<InstCounterType>> inst_counter_types() {
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return make_range(enum_iterator<InstCounterType>(VM_CNT),
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enum_iterator<InstCounterType>(NUM_INST_CNTS));
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}
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using RegInterval = std::pair<int, int>;
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struct {
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unsigned VmcntMax;
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unsigned ExpcntMax;
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unsigned LgkmcntMax;
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unsigned VscntMax;
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} HardwareLimits;
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struct {
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unsigned VGPR0;
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unsigned VGPRL;
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unsigned SGPR0;
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unsigned SGPRL;
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} RegisterEncoding;
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enum WaitEventType {
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VMEM_ACCESS, // vector-memory read & write
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VMEM_READ_ACCESS, // vector-memory read
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VMEM_WRITE_ACCESS,// vector-memory write
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LDS_ACCESS, // lds read & write
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GDS_ACCESS, // gds read & write
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SQ_MESSAGE, // send message
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SMEM_ACCESS, // scalar-memory read & write
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EXP_GPR_LOCK, // export holding on its data src
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GDS_GPR_LOCK, // GDS holding on its data and addr src
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EXP_POS_ACCESS, // write to export position
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EXP_PARAM_ACCESS, // write to export parameter
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VMW_GPR_LOCK, // vector-memory write holding on its data src
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NUM_WAIT_EVENTS,
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};
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static const unsigned WaitEventMaskForInst[NUM_INST_CNTS] = {
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(1 << VMEM_ACCESS) | (1 << VMEM_READ_ACCESS),
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(1 << SMEM_ACCESS) | (1 << LDS_ACCESS) | (1 << GDS_ACCESS) |
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(1 << SQ_MESSAGE),
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(1 << EXP_GPR_LOCK) | (1 << GDS_GPR_LOCK) | (1 << VMW_GPR_LOCK) |
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(1 << EXP_PARAM_ACCESS) | (1 << EXP_POS_ACCESS),
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(1 << VMEM_WRITE_ACCESS)
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};
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// The mapping is:
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// 0 .. SQ_MAX_PGM_VGPRS-1 real VGPRs
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// SQ_MAX_PGM_VGPRS .. NUM_ALL_VGPRS-1 extra VGPR-like slots
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// NUM_ALL_VGPRS .. NUM_ALL_VGPRS+SQ_MAX_PGM_SGPRS-1 real SGPRs
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// We reserve a fixed number of VGPR slots in the scoring tables for
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// special tokens like SCMEM_LDS (needed for buffer load to LDS).
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enum RegisterMapping {
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SQ_MAX_PGM_VGPRS = 256, // Maximum programmable VGPRs across all targets.
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SQ_MAX_PGM_SGPRS = 256, // Maximum programmable SGPRs across all targets.
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NUM_EXTRA_VGPRS = 1, // A reserved slot for DS.
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EXTRA_VGPR_LDS = 0, // This is a placeholder the Shader algorithm uses.
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NUM_ALL_VGPRS = SQ_MAX_PGM_VGPRS + NUM_EXTRA_VGPRS, // Where SGPR starts.
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};
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// Enumerate different types of result-returning VMEM operations. Although
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// s_waitcnt orders them all with a single vmcnt counter, in the absence of
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// s_waitcnt only instructions of the same VmemType are guaranteed to write
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// their results in order -- so there is no need to insert an s_waitcnt between
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// two instructions of the same type that write the same vgpr.
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enum VmemType {
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// BUF instructions and MIMG instructions without a sampler.
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VMEM_NOSAMPLER,
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// MIMG instructions with a sampler.
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VMEM_SAMPLER,
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};
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VmemType getVmemType(const MachineInstr &Inst) {
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assert(SIInstrInfo::isVMEM(Inst));
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if (!SIInstrInfo::isMIMG(Inst))
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return VMEM_NOSAMPLER;
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const AMDGPU::MIMGInfo *Info = AMDGPU::getMIMGInfo(Inst.getOpcode());
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return AMDGPU::getMIMGBaseOpcodeInfo(Info->BaseOpcode)->Sampler
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? VMEM_SAMPLER
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: VMEM_NOSAMPLER;
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}
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void addWait(AMDGPU::Waitcnt &Wait, InstCounterType T, unsigned Count) {
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switch (T) {
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case VM_CNT:
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Wait.VmCnt = std::min(Wait.VmCnt, Count);
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break;
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case EXP_CNT:
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Wait.ExpCnt = std::min(Wait.ExpCnt, Count);
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break;
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case LGKM_CNT:
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Wait.LgkmCnt = std::min(Wait.LgkmCnt, Count);
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break;
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case VS_CNT:
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Wait.VsCnt = std::min(Wait.VsCnt, Count);
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break;
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default:
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llvm_unreachable("bad InstCounterType");
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}
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}
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// This objects maintains the current score brackets of each wait counter, and
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// a per-register scoreboard for each wait counter.
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//
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// We also maintain the latest score for every event type that can change the
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// waitcnt in order to know if there are multiple types of events within
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// the brackets. When multiple types of event happen in the bracket,
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// wait count may get decreased out of order, therefore we need to put in
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// "s_waitcnt 0" before use.
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class WaitcntBrackets {
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public:
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WaitcntBrackets(const GCNSubtarget *SubTarget) : ST(SubTarget) {}
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static unsigned getWaitCountMax(InstCounterType T) {
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switch (T) {
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case VM_CNT:
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return HardwareLimits.VmcntMax;
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case LGKM_CNT:
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return HardwareLimits.LgkmcntMax;
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case EXP_CNT:
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return HardwareLimits.ExpcntMax;
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case VS_CNT:
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return HardwareLimits.VscntMax;
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default:
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break;
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}
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return 0;
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}
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unsigned getScoreLB(InstCounterType T) const {
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assert(T < NUM_INST_CNTS);
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return ScoreLBs[T];
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}
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unsigned getScoreUB(InstCounterType T) const {
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assert(T < NUM_INST_CNTS);
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return ScoreUBs[T];
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}
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// Mapping from event to counter.
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InstCounterType eventCounter(WaitEventType E) {
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if (WaitEventMaskForInst[VM_CNT] & (1 << E))
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return VM_CNT;
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if (WaitEventMaskForInst[LGKM_CNT] & (1 << E))
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return LGKM_CNT;
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if (WaitEventMaskForInst[VS_CNT] & (1 << E))
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return VS_CNT;
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assert(WaitEventMaskForInst[EXP_CNT] & (1 << E));
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return EXP_CNT;
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}
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unsigned getRegScore(int GprNo, InstCounterType T) {
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if (GprNo < NUM_ALL_VGPRS) {
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return VgprScores[T][GprNo];
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}
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assert(T == LGKM_CNT);
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return SgprScores[GprNo - NUM_ALL_VGPRS];
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}
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bool merge(const WaitcntBrackets &Other);
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RegInterval getRegInterval(const MachineInstr *MI, const SIInstrInfo *TII,
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const MachineRegisterInfo *MRI,
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const SIRegisterInfo *TRI, unsigned OpNo) const;
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bool counterOutOfOrder(InstCounterType T) const;
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bool simplifyWaitcnt(AMDGPU::Waitcnt &Wait) const;
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bool simplifyWaitcnt(InstCounterType T, unsigned &Count) const;
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void determineWait(InstCounterType T, unsigned ScoreToWait,
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AMDGPU::Waitcnt &Wait) const;
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void applyWaitcnt(const AMDGPU::Waitcnt &Wait);
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void applyWaitcnt(InstCounterType T, unsigned Count);
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void updateByEvent(const SIInstrInfo *TII, const SIRegisterInfo *TRI,
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const MachineRegisterInfo *MRI, WaitEventType E,
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MachineInstr &MI);
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bool hasPending() const { return PendingEvents != 0; }
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bool hasPendingEvent(WaitEventType E) const {
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return PendingEvents & (1 << E);
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}
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bool hasMixedPendingEvents(InstCounterType T) const {
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unsigned Events = PendingEvents & WaitEventMaskForInst[T];
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// Return true if more than one bit is set in Events.
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return Events & (Events - 1);
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}
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bool hasPendingFlat() const {
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return ((LastFlat[LGKM_CNT] > ScoreLBs[LGKM_CNT] &&
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LastFlat[LGKM_CNT] <= ScoreUBs[LGKM_CNT]) ||
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(LastFlat[VM_CNT] > ScoreLBs[VM_CNT] &&
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LastFlat[VM_CNT] <= ScoreUBs[VM_CNT]));
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}
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void setPendingFlat() {
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LastFlat[VM_CNT] = ScoreUBs[VM_CNT];
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LastFlat[LGKM_CNT] = ScoreUBs[LGKM_CNT];
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}
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// Return true if there might be pending writes to the specified vgpr by VMEM
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// instructions with types different from V.
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bool hasOtherPendingVmemTypes(int GprNo, VmemType V) const {
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assert(GprNo < NUM_ALL_VGPRS);
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return VgprVmemTypes[GprNo] & ~(1 << V);
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}
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void clearVgprVmemTypes(int GprNo) {
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assert(GprNo < NUM_ALL_VGPRS);
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VgprVmemTypes[GprNo] = 0;
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}
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void print(raw_ostream &);
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void dump() { print(dbgs()); }
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private:
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struct MergeInfo {
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unsigned OldLB;
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unsigned OtherLB;
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unsigned MyShift;
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unsigned OtherShift;
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};
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static bool mergeScore(const MergeInfo &M, unsigned &Score,
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unsigned OtherScore);
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void setScoreLB(InstCounterType T, unsigned Val) {
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assert(T < NUM_INST_CNTS);
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ScoreLBs[T] = Val;
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}
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void setScoreUB(InstCounterType T, unsigned Val) {
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assert(T < NUM_INST_CNTS);
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ScoreUBs[T] = Val;
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if (T == EXP_CNT) {
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unsigned UB = ScoreUBs[T] - getWaitCountMax(EXP_CNT);
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if (ScoreLBs[T] < UB && UB < ScoreUBs[T])
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ScoreLBs[T] = UB;
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}
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}
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void setRegScore(int GprNo, InstCounterType T, unsigned Val) {
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if (GprNo < NUM_ALL_VGPRS) {
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VgprUB = std::max(VgprUB, GprNo);
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VgprScores[T][GprNo] = Val;
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} else {
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assert(T == LGKM_CNT);
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SgprUB = std::max(SgprUB, GprNo - NUM_ALL_VGPRS);
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SgprScores[GprNo - NUM_ALL_VGPRS] = Val;
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}
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}
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void setExpScore(const MachineInstr *MI, const SIInstrInfo *TII,
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const SIRegisterInfo *TRI, const MachineRegisterInfo *MRI,
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unsigned OpNo, unsigned Val);
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const GCNSubtarget *ST = nullptr;
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unsigned ScoreLBs[NUM_INST_CNTS] = {0};
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unsigned ScoreUBs[NUM_INST_CNTS] = {0};
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unsigned PendingEvents = 0;
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// Remember the last flat memory operation.
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unsigned LastFlat[NUM_INST_CNTS] = {0};
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// wait_cnt scores for every vgpr.
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// Keep track of the VgprUB and SgprUB to make merge at join efficient.
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int VgprUB = -1;
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int SgprUB = -1;
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unsigned VgprScores[NUM_INST_CNTS][NUM_ALL_VGPRS] = {{0}};
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// Wait cnt scores for every sgpr, only lgkmcnt is relevant.
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unsigned SgprScores[SQ_MAX_PGM_SGPRS] = {0};
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// Bitmask of the VmemTypes of VMEM instructions that might have a pending
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// write to each vgpr.
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unsigned char VgprVmemTypes[NUM_ALL_VGPRS] = {0};
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};
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class SIInsertWaitcnts : public MachineFunctionPass {
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private:
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const GCNSubtarget *ST = nullptr;
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const SIInstrInfo *TII = nullptr;
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const SIRegisterInfo *TRI = nullptr;
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const MachineRegisterInfo *MRI = nullptr;
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AMDGPU::IsaVersion IV;
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DenseSet<MachineInstr *> TrackedWaitcntSet;
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DenseMap<const Value *, MachineBasicBlock *> SLoadAddresses;
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MachinePostDominatorTree *PDT;
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struct BlockInfo {
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MachineBasicBlock *MBB;
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std::unique_ptr<WaitcntBrackets> Incoming;
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bool Dirty = true;
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explicit BlockInfo(MachineBasicBlock *MBB) : MBB(MBB) {}
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};
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MapVector<MachineBasicBlock *, BlockInfo> BlockInfos;
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// ForceEmitZeroWaitcnts: force all waitcnts insts to be s_waitcnt 0
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// because of amdgpu-waitcnt-forcezero flag
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bool ForceEmitZeroWaitcnts;
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bool ForceEmitWaitcnt[NUM_INST_CNTS];
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public:
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static char ID;
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SIInsertWaitcnts() : MachineFunctionPass(ID) {
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(void)ForceExpCounter;
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(void)ForceLgkmCounter;
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(void)ForceVMCounter;
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}
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bool runOnMachineFunction(MachineFunction &MF) override;
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StringRef getPassName() const override {
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return "SI insert wait instructions";
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}
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void getAnalysisUsage(AnalysisUsage &AU) const override {
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AU.setPreservesCFG();
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AU.addRequired<MachinePostDominatorTree>();
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MachineFunctionPass::getAnalysisUsage(AU);
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}
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bool isForceEmitWaitcnt() const {
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for (auto T : inst_counter_types())
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if (ForceEmitWaitcnt[T])
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return true;
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return false;
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}
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void setForceEmitWaitcnt() {
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// For non-debug builds, ForceEmitWaitcnt has been initialized to false;
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// For debug builds, get the debug counter info and adjust if need be
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#ifndef NDEBUG
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if (DebugCounter::isCounterSet(ForceExpCounter) &&
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DebugCounter::shouldExecute(ForceExpCounter)) {
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ForceEmitWaitcnt[EXP_CNT] = true;
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} else {
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ForceEmitWaitcnt[EXP_CNT] = false;
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}
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if (DebugCounter::isCounterSet(ForceLgkmCounter) &&
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DebugCounter::shouldExecute(ForceLgkmCounter)) {
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ForceEmitWaitcnt[LGKM_CNT] = true;
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} else {
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ForceEmitWaitcnt[LGKM_CNT] = false;
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}
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if (DebugCounter::isCounterSet(ForceVMCounter) &&
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DebugCounter::shouldExecute(ForceVMCounter)) {
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ForceEmitWaitcnt[VM_CNT] = true;
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} else {
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ForceEmitWaitcnt[VM_CNT] = false;
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}
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#endif // NDEBUG
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}
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bool mayAccessVMEMThroughFlat(const MachineInstr &MI) const;
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bool mayAccessLDSThroughFlat(const MachineInstr &MI) const;
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bool generateWaitcntInstBefore(MachineInstr &MI,
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WaitcntBrackets &ScoreBrackets,
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MachineInstr *OldWaitcntInstr);
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void updateEventWaitcntAfter(MachineInstr &Inst,
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WaitcntBrackets *ScoreBrackets);
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bool insertWaitcntInBlock(MachineFunction &MF, MachineBasicBlock &Block,
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WaitcntBrackets &ScoreBrackets);
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};
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} // end anonymous namespace
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RegInterval WaitcntBrackets::getRegInterval(const MachineInstr *MI,
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const SIInstrInfo *TII,
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const MachineRegisterInfo *MRI,
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const SIRegisterInfo *TRI,
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unsigned OpNo) const {
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const MachineOperand &Op = MI->getOperand(OpNo);
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assert(Op.isReg());
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if (!TRI->isInAllocatableClass(Op.getReg()) || TRI->isAGPR(*MRI, Op.getReg()))
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return {-1, -1};
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// A use via a PW operand does not need a waitcnt.
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// A partial write is not a WAW.
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assert(!Op.getSubReg() || !Op.isUndef());
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RegInterval Result;
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unsigned Reg = TRI->getEncodingValue(AMDGPU::getMCReg(Op.getReg(), *ST));
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if (TRI->isVGPR(*MRI, Op.getReg())) {
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assert(Reg >= RegisterEncoding.VGPR0 && Reg <= RegisterEncoding.VGPRL);
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Result.first = Reg - RegisterEncoding.VGPR0;
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assert(Result.first >= 0 && Result.first < SQ_MAX_PGM_VGPRS);
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} else if (TRI->isSGPRReg(*MRI, Op.getReg())) {
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assert(Reg >= RegisterEncoding.SGPR0 && Reg < SQ_MAX_PGM_SGPRS);
|
|
Result.first = Reg - RegisterEncoding.SGPR0 + NUM_ALL_VGPRS;
|
|
assert(Result.first >= NUM_ALL_VGPRS &&
|
|
Result.first < SQ_MAX_PGM_SGPRS + NUM_ALL_VGPRS);
|
|
}
|
|
// TODO: Handle TTMP
|
|
// else if (TRI->isTTMP(*MRI, Reg.getReg())) ...
|
|
else
|
|
return {-1, -1};
|
|
|
|
const TargetRegisterClass *RC = TII->getOpRegClass(*MI, OpNo);
|
|
unsigned Size = TRI->getRegSizeInBits(*RC);
|
|
Result.second = Result.first + ((Size + 16) / 32);
|
|
|
|
return Result;
|
|
}
|
|
|
|
void WaitcntBrackets::setExpScore(const MachineInstr *MI,
|
|
const SIInstrInfo *TII,
|
|
const SIRegisterInfo *TRI,
|
|
const MachineRegisterInfo *MRI, unsigned OpNo,
|
|
unsigned Val) {
|
|
RegInterval Interval = getRegInterval(MI, TII, MRI, TRI, OpNo);
|
|
assert(TRI->isVGPR(*MRI, MI->getOperand(OpNo).getReg()));
|
|
for (int RegNo = Interval.first; RegNo < Interval.second; ++RegNo) {
|
|
setRegScore(RegNo, EXP_CNT, Val);
|
|
}
|
|
}
|
|
|
|
void WaitcntBrackets::updateByEvent(const SIInstrInfo *TII,
|
|
const SIRegisterInfo *TRI,
|
|
const MachineRegisterInfo *MRI,
|
|
WaitEventType E, MachineInstr &Inst) {
|
|
InstCounterType T = eventCounter(E);
|
|
unsigned CurrScore = getScoreUB(T) + 1;
|
|
if (CurrScore == 0)
|
|
report_fatal_error("InsertWaitcnt score wraparound");
|
|
// PendingEvents and ScoreUB need to be update regardless if this event
|
|
// changes the score of a register or not.
|
|
// Examples including vm_cnt when buffer-store or lgkm_cnt when send-message.
|
|
PendingEvents |= 1 << E;
|
|
setScoreUB(T, CurrScore);
|
|
|
|
if (T == EXP_CNT) {
|
|
// Put score on the source vgprs. If this is a store, just use those
|
|
// specific register(s).
|
|
if (TII->isDS(Inst) && (Inst.mayStore() || Inst.mayLoad())) {
|
|
int AddrOpIdx =
|
|
AMDGPU::getNamedOperandIdx(Inst.getOpcode(), AMDGPU::OpName::addr);
|
|
// All GDS operations must protect their address register (same as
|
|
// export.)
|
|
if (AddrOpIdx != -1) {
|
|
setExpScore(&Inst, TII, TRI, MRI, AddrOpIdx, CurrScore);
|
|
}
|
|
|
|
if (Inst.mayStore()) {
|
|
if (AMDGPU::getNamedOperandIdx(Inst.getOpcode(),
|
|
AMDGPU::OpName::data0) != -1) {
|
|
setExpScore(
|
|
&Inst, TII, TRI, MRI,
|
|
AMDGPU::getNamedOperandIdx(Inst.getOpcode(), AMDGPU::OpName::data0),
|
|
CurrScore);
|
|
}
|
|
if (AMDGPU::getNamedOperandIdx(Inst.getOpcode(),
|
|
AMDGPU::OpName::data1) != -1) {
|
|
setExpScore(&Inst, TII, TRI, MRI,
|
|
AMDGPU::getNamedOperandIdx(Inst.getOpcode(),
|
|
AMDGPU::OpName::data1),
|
|
CurrScore);
|
|
}
|
|
} else if (AMDGPU::getAtomicNoRetOp(Inst.getOpcode()) != -1 &&
|
|
Inst.getOpcode() != AMDGPU::DS_GWS_INIT &&
|
|
Inst.getOpcode() != AMDGPU::DS_GWS_SEMA_V &&
|
|
Inst.getOpcode() != AMDGPU::DS_GWS_SEMA_BR &&
|
|
Inst.getOpcode() != AMDGPU::DS_GWS_SEMA_P &&
|
|
Inst.getOpcode() != AMDGPU::DS_GWS_BARRIER &&
|
|
Inst.getOpcode() != AMDGPU::DS_APPEND &&
|
|
Inst.getOpcode() != AMDGPU::DS_CONSUME &&
|
|
Inst.getOpcode() != AMDGPU::DS_ORDERED_COUNT) {
|
|
for (unsigned I = 0, E = Inst.getNumOperands(); I != E; ++I) {
|
|
const MachineOperand &Op = Inst.getOperand(I);
|
|
if (Op.isReg() && !Op.isDef() && TRI->isVGPR(*MRI, Op.getReg())) {
|
|
setExpScore(&Inst, TII, TRI, MRI, I, CurrScore);
|
|
}
|
|
}
|
|
}
|
|
} else if (TII->isFLAT(Inst)) {
|
|
if (Inst.mayStore()) {
|
|
setExpScore(
|
|
&Inst, TII, TRI, MRI,
|
|
AMDGPU::getNamedOperandIdx(Inst.getOpcode(), AMDGPU::OpName::data),
|
|
CurrScore);
|
|
} else if (AMDGPU::getAtomicNoRetOp(Inst.getOpcode()) != -1) {
|
|
setExpScore(
|
|
&Inst, TII, TRI, MRI,
|
|
AMDGPU::getNamedOperandIdx(Inst.getOpcode(), AMDGPU::OpName::data),
|
|
CurrScore);
|
|
}
|
|
} else if (TII->isMIMG(Inst)) {
|
|
if (Inst.mayStore()) {
|
|
setExpScore(&Inst, TII, TRI, MRI, 0, CurrScore);
|
|
} else if (AMDGPU::getAtomicNoRetOp(Inst.getOpcode()) != -1) {
|
|
setExpScore(
|
|
&Inst, TII, TRI, MRI,
|
|
AMDGPU::getNamedOperandIdx(Inst.getOpcode(), AMDGPU::OpName::data),
|
|
CurrScore);
|
|
}
|
|
} else if (TII->isMTBUF(Inst)) {
|
|
if (Inst.mayStore()) {
|
|
setExpScore(&Inst, TII, TRI, MRI, 0, CurrScore);
|
|
}
|
|
} else if (TII->isMUBUF(Inst)) {
|
|
if (Inst.mayStore()) {
|
|
setExpScore(&Inst, TII, TRI, MRI, 0, CurrScore);
|
|
} else if (AMDGPU::getAtomicNoRetOp(Inst.getOpcode()) != -1) {
|
|
setExpScore(
|
|
&Inst, TII, TRI, MRI,
|
|
AMDGPU::getNamedOperandIdx(Inst.getOpcode(), AMDGPU::OpName::data),
|
|
CurrScore);
|
|
}
|
|
} else {
|
|
if (TII->isEXP(Inst)) {
|
|
// For export the destination registers are really temps that
|
|
// can be used as the actual source after export patching, so
|
|
// we need to treat them like sources and set the EXP_CNT
|
|
// score.
|
|
for (unsigned I = 0, E = Inst.getNumOperands(); I != E; ++I) {
|
|
MachineOperand &DefMO = Inst.getOperand(I);
|
|
if (DefMO.isReg() && DefMO.isDef() &&
|
|
TRI->isVGPR(*MRI, DefMO.getReg())) {
|
|
setRegScore(
|
|
TRI->getEncodingValue(AMDGPU::getMCReg(DefMO.getReg(), *ST)),
|
|
EXP_CNT, CurrScore);
|
|
}
|
|
}
|
|
}
|
|
for (unsigned I = 0, E = Inst.getNumOperands(); I != E; ++I) {
|
|
MachineOperand &MO = Inst.getOperand(I);
|
|
if (MO.isReg() && !MO.isDef() && TRI->isVGPR(*MRI, MO.getReg())) {
|
|
setExpScore(&Inst, TII, TRI, MRI, I, CurrScore);
|
|
}
|
|
}
|
|
}
|
|
#if 0 // TODO: check if this is handled by MUBUF code above.
|
|
} else if (Inst.getOpcode() == AMDGPU::BUFFER_STORE_DWORD ||
|
|
Inst.getOpcode() == AMDGPU::BUFFER_STORE_DWORDX2 ||
|
|
Inst.getOpcode() == AMDGPU::BUFFER_STORE_DWORDX4) {
|
|
MachineOperand *MO = TII->getNamedOperand(Inst, AMDGPU::OpName::data);
|
|
unsigned OpNo;//TODO: find the OpNo for this operand;
|
|
RegInterval Interval = getRegInterval(&Inst, TII, MRI, TRI, OpNo);
|
|
for (int RegNo = Interval.first; RegNo < Interval.second;
|
|
++RegNo) {
|
|
setRegScore(RegNo + NUM_ALL_VGPRS, t, CurrScore);
|
|
}
|
|
#endif
|
|
} else {
|
|
// Match the score to the destination registers.
|
|
for (unsigned I = 0, E = Inst.getNumOperands(); I != E; ++I) {
|
|
auto &Op = Inst.getOperand(I);
|
|
if (!Op.isReg() || !Op.isDef())
|
|
continue;
|
|
RegInterval Interval = getRegInterval(&Inst, TII, MRI, TRI, I);
|
|
if (T == VM_CNT) {
|
|
if (Interval.first >= NUM_ALL_VGPRS)
|
|
continue;
|
|
if (SIInstrInfo::isVMEM(Inst)) {
|
|
VmemType V = getVmemType(Inst);
|
|
for (int RegNo = Interval.first; RegNo < Interval.second; ++RegNo)
|
|
VgprVmemTypes[RegNo] |= 1 << V;
|
|
}
|
|
}
|
|
for (int RegNo = Interval.first; RegNo < Interval.second; ++RegNo) {
|
|
setRegScore(RegNo, T, CurrScore);
|
|
}
|
|
}
|
|
if (TII->isDS(Inst) && Inst.mayStore()) {
|
|
setRegScore(SQ_MAX_PGM_VGPRS + EXTRA_VGPR_LDS, T, CurrScore);
|
|
}
|
|
}
|
|
}
|
|
|
|
void WaitcntBrackets::print(raw_ostream &OS) {
|
|
OS << '\n';
|
|
for (auto T : inst_counter_types()) {
|
|
unsigned LB = getScoreLB(T);
|
|
unsigned UB = getScoreUB(T);
|
|
|
|
switch (T) {
|
|
case VM_CNT:
|
|
OS << " VM_CNT(" << UB - LB << "): ";
|
|
break;
|
|
case LGKM_CNT:
|
|
OS << " LGKM_CNT(" << UB - LB << "): ";
|
|
break;
|
|
case EXP_CNT:
|
|
OS << " EXP_CNT(" << UB - LB << "): ";
|
|
break;
|
|
case VS_CNT:
|
|
OS << " VS_CNT(" << UB - LB << "): ";
|
|
break;
|
|
default:
|
|
OS << " UNKNOWN(" << UB - LB << "): ";
|
|
break;
|
|
}
|
|
|
|
if (LB < UB) {
|
|
// Print vgpr scores.
|
|
for (int J = 0; J <= VgprUB; J++) {
|
|
unsigned RegScore = getRegScore(J, T);
|
|
if (RegScore <= LB)
|
|
continue;
|
|
unsigned RelScore = RegScore - LB - 1;
|
|
if (J < SQ_MAX_PGM_VGPRS + EXTRA_VGPR_LDS) {
|
|
OS << RelScore << ":v" << J << " ";
|
|
} else {
|
|
OS << RelScore << ":ds ";
|
|
}
|
|
}
|
|
// Also need to print sgpr scores for lgkm_cnt.
|
|
if (T == LGKM_CNT) {
|
|
for (int J = 0; J <= SgprUB; J++) {
|
|
unsigned RegScore = getRegScore(J + NUM_ALL_VGPRS, LGKM_CNT);
|
|
if (RegScore <= LB)
|
|
continue;
|
|
unsigned RelScore = RegScore - LB - 1;
|
|
OS << RelScore << ":s" << J << " ";
|
|
}
|
|
}
|
|
}
|
|
OS << '\n';
|
|
}
|
|
OS << '\n';
|
|
}
|
|
|
|
/// Simplify the waitcnt, in the sense of removing redundant counts, and return
|
|
/// whether a waitcnt instruction is needed at all.
|
|
bool WaitcntBrackets::simplifyWaitcnt(AMDGPU::Waitcnt &Wait) const {
|
|
return simplifyWaitcnt(VM_CNT, Wait.VmCnt) |
|
|
simplifyWaitcnt(EXP_CNT, Wait.ExpCnt) |
|
|
simplifyWaitcnt(LGKM_CNT, Wait.LgkmCnt) |
|
|
simplifyWaitcnt(VS_CNT, Wait.VsCnt);
|
|
}
|
|
|
|
bool WaitcntBrackets::simplifyWaitcnt(InstCounterType T,
|
|
unsigned &Count) const {
|
|
const unsigned LB = getScoreLB(T);
|
|
const unsigned UB = getScoreUB(T);
|
|
if (Count < UB && UB - Count > LB)
|
|
return true;
|
|
|
|
Count = ~0u;
|
|
return false;
|
|
}
|
|
|
|
void WaitcntBrackets::determineWait(InstCounterType T, unsigned ScoreToWait,
|
|
AMDGPU::Waitcnt &Wait) const {
|
|
// If the score of src_operand falls within the bracket, we need an
|
|
// s_waitcnt instruction.
|
|
const unsigned LB = getScoreLB(T);
|
|
const unsigned UB = getScoreUB(T);
|
|
if ((UB >= ScoreToWait) && (ScoreToWait > LB)) {
|
|
if ((T == VM_CNT || T == LGKM_CNT) &&
|
|
hasPendingFlat() &&
|
|
!ST->hasFlatLgkmVMemCountInOrder()) {
|
|
// If there is a pending FLAT operation, and this is a VMem or LGKM
|
|
// waitcnt and the target can report early completion, then we need
|
|
// to force a waitcnt 0.
|
|
addWait(Wait, T, 0);
|
|
} else if (counterOutOfOrder(T)) {
|
|
// Counter can get decremented out-of-order when there
|
|
// are multiple types event in the bracket. Also emit an s_wait counter
|
|
// with a conservative value of 0 for the counter.
|
|
addWait(Wait, T, 0);
|
|
} else {
|
|
// If a counter has been maxed out avoid overflow by waiting for
|
|
// MAX(CounterType) - 1 instead.
|
|
unsigned NeededWait = std::min(UB - ScoreToWait, getWaitCountMax(T) - 1);
|
|
addWait(Wait, T, NeededWait);
|
|
}
|
|
}
|
|
}
|
|
|
|
void WaitcntBrackets::applyWaitcnt(const AMDGPU::Waitcnt &Wait) {
|
|
applyWaitcnt(VM_CNT, Wait.VmCnt);
|
|
applyWaitcnt(EXP_CNT, Wait.ExpCnt);
|
|
applyWaitcnt(LGKM_CNT, Wait.LgkmCnt);
|
|
applyWaitcnt(VS_CNT, Wait.VsCnt);
|
|
}
|
|
|
|
void WaitcntBrackets::applyWaitcnt(InstCounterType T, unsigned Count) {
|
|
const unsigned UB = getScoreUB(T);
|
|
if (Count >= UB)
|
|
return;
|
|
if (Count != 0) {
|
|
if (counterOutOfOrder(T))
|
|
return;
|
|
setScoreLB(T, std::max(getScoreLB(T), UB - Count));
|
|
} else {
|
|
setScoreLB(T, UB);
|
|
PendingEvents &= ~WaitEventMaskForInst[T];
|
|
}
|
|
}
|
|
|
|
// Where there are multiple types of event in the bracket of a counter,
|
|
// the decrement may go out of order.
|
|
bool WaitcntBrackets::counterOutOfOrder(InstCounterType T) const {
|
|
// Scalar memory read always can go out of order.
|
|
if (T == LGKM_CNT && hasPendingEvent(SMEM_ACCESS))
|
|
return true;
|
|
return hasMixedPendingEvents(T);
|
|
}
|
|
|
|
INITIALIZE_PASS_BEGIN(SIInsertWaitcnts, DEBUG_TYPE, "SI Insert Waitcnts", false,
|
|
false)
|
|
INITIALIZE_PASS_DEPENDENCY(MachinePostDominatorTree)
|
|
INITIALIZE_PASS_END(SIInsertWaitcnts, DEBUG_TYPE, "SI Insert Waitcnts", false,
|
|
false)
|
|
|
|
char SIInsertWaitcnts::ID = 0;
|
|
|
|
char &llvm::SIInsertWaitcntsID = SIInsertWaitcnts::ID;
|
|
|
|
FunctionPass *llvm::createSIInsertWaitcntsPass() {
|
|
return new SIInsertWaitcnts();
|
|
}
|
|
|
|
static bool readsVCCZ(const MachineInstr &MI) {
|
|
unsigned Opc = MI.getOpcode();
|
|
return (Opc == AMDGPU::S_CBRANCH_VCCNZ || Opc == AMDGPU::S_CBRANCH_VCCZ) &&
|
|
!MI.getOperand(1).isUndef();
|
|
}
|
|
|
|
/// \returns true if the callee inserts an s_waitcnt 0 on function entry.
|
|
static bool callWaitsOnFunctionEntry(const MachineInstr &MI) {
|
|
// Currently all conventions wait, but this may not always be the case.
|
|
//
|
|
// TODO: If IPRA is enabled, and the callee is isSafeForNoCSROpt, it may make
|
|
// senses to omit the wait and do it in the caller.
|
|
return true;
|
|
}
|
|
|
|
/// \returns true if the callee is expected to wait for any outstanding waits
|
|
/// before returning.
|
|
static bool callWaitsOnFunctionReturn(const MachineInstr &MI) {
|
|
return true;
|
|
}
|
|
|
|
/// Generate s_waitcnt instruction to be placed before cur_Inst.
|
|
/// Instructions of a given type are returned in order,
|
|
/// but instructions of different types can complete out of order.
|
|
/// We rely on this in-order completion
|
|
/// and simply assign a score to the memory access instructions.
|
|
/// We keep track of the active "score bracket" to determine
|
|
/// if an access of a memory read requires an s_waitcnt
|
|
/// and if so what the value of each counter is.
|
|
/// The "score bracket" is bound by the lower bound and upper bound
|
|
/// scores (*_score_LB and *_score_ub respectively).
|
|
bool SIInsertWaitcnts::generateWaitcntInstBefore(
|
|
MachineInstr &MI, WaitcntBrackets &ScoreBrackets,
|
|
MachineInstr *OldWaitcntInstr) {
|
|
setForceEmitWaitcnt();
|
|
bool IsForceEmitWaitcnt = isForceEmitWaitcnt();
|
|
|
|
if (MI.isMetaInstruction())
|
|
return false;
|
|
|
|
AMDGPU::Waitcnt Wait;
|
|
|
|
// See if this instruction has a forced S_WAITCNT VM.
|
|
// TODO: Handle other cases of NeedsWaitcntVmBefore()
|
|
if (MI.getOpcode() == AMDGPU::BUFFER_WBINVL1 ||
|
|
MI.getOpcode() == AMDGPU::BUFFER_WBINVL1_SC ||
|
|
MI.getOpcode() == AMDGPU::BUFFER_WBINVL1_VOL ||
|
|
MI.getOpcode() == AMDGPU::BUFFER_GL0_INV ||
|
|
MI.getOpcode() == AMDGPU::BUFFER_GL1_INV) {
|
|
Wait.VmCnt = 0;
|
|
}
|
|
|
|
// All waits must be resolved at call return.
|
|
// NOTE: this could be improved with knowledge of all call sites or
|
|
// with knowledge of the called routines.
|
|
if (MI.getOpcode() == AMDGPU::SI_RETURN_TO_EPILOG ||
|
|
MI.getOpcode() == AMDGPU::S_SETPC_B64_return ||
|
|
(MI.isReturn() && MI.isCall() && !callWaitsOnFunctionEntry(MI))) {
|
|
Wait = Wait.combined(AMDGPU::Waitcnt::allZero(ST->hasVscnt()));
|
|
}
|
|
// Resolve vm waits before gs-done.
|
|
else if ((MI.getOpcode() == AMDGPU::S_SENDMSG ||
|
|
MI.getOpcode() == AMDGPU::S_SENDMSGHALT) &&
|
|
((MI.getOperand(0).getImm() & AMDGPU::SendMsg::ID_MASK_) ==
|
|
AMDGPU::SendMsg::ID_GS_DONE)) {
|
|
Wait.VmCnt = 0;
|
|
}
|
|
#if 0 // TODO: the following blocks of logic when we have fence.
|
|
else if (MI.getOpcode() == SC_FENCE) {
|
|
const unsigned int group_size =
|
|
context->shader_info->GetMaxThreadGroupSize();
|
|
// group_size == 0 means thread group size is unknown at compile time
|
|
const bool group_is_multi_wave =
|
|
(group_size == 0 || group_size > target_info->GetWaveFrontSize());
|
|
const bool fence_is_global = !((SCInstInternalMisc*)Inst)->IsGroupFence();
|
|
|
|
for (unsigned int i = 0; i < Inst->NumSrcOperands(); i++) {
|
|
SCRegType src_type = Inst->GetSrcType(i);
|
|
switch (src_type) {
|
|
case SCMEM_LDS:
|
|
if (group_is_multi_wave ||
|
|
context->OptFlagIsOn(OPT_R1100_LDSMEM_FENCE_CHICKEN_BIT)) {
|
|
EmitWaitcnt |= ScoreBrackets->updateByWait(LGKM_CNT,
|
|
ScoreBrackets->getScoreUB(LGKM_CNT));
|
|
// LDS may have to wait for VM_CNT after buffer load to LDS
|
|
if (target_info->HasBufferLoadToLDS()) {
|
|
EmitWaitcnt |= ScoreBrackets->updateByWait(VM_CNT,
|
|
ScoreBrackets->getScoreUB(VM_CNT));
|
|
}
|
|
}
|
|
break;
|
|
|
|
case SCMEM_GDS:
|
|
if (group_is_multi_wave || fence_is_global) {
|
|
EmitWaitcnt |= ScoreBrackets->updateByWait(EXP_CNT,
|
|
ScoreBrackets->getScoreUB(EXP_CNT));
|
|
EmitWaitcnt |= ScoreBrackets->updateByWait(LGKM_CNT,
|
|
ScoreBrackets->getScoreUB(LGKM_CNT));
|
|
}
|
|
break;
|
|
|
|
case SCMEM_UAV:
|
|
case SCMEM_TFBUF:
|
|
case SCMEM_RING:
|
|
case SCMEM_SCATTER:
|
|
if (group_is_multi_wave || fence_is_global) {
|
|
EmitWaitcnt |= ScoreBrackets->updateByWait(EXP_CNT,
|
|
ScoreBrackets->getScoreUB(EXP_CNT));
|
|
EmitWaitcnt |= ScoreBrackets->updateByWait(VM_CNT,
|
|
ScoreBrackets->getScoreUB(VM_CNT));
|
|
}
|
|
break;
|
|
|
|
case SCMEM_SCRATCH:
|
|
default:
|
|
break;
|
|
}
|
|
}
|
|
}
|
|
#endif
|
|
|
|
// Export & GDS instructions do not read the EXEC mask until after the export
|
|
// is granted (which can occur well after the instruction is issued).
|
|
// The shader program must flush all EXP operations on the export-count
|
|
// before overwriting the EXEC mask.
|
|
else {
|
|
if (MI.modifiesRegister(AMDGPU::EXEC, TRI)) {
|
|
// Export and GDS are tracked individually, either may trigger a waitcnt
|
|
// for EXEC.
|
|
if (ScoreBrackets.hasPendingEvent(EXP_GPR_LOCK) ||
|
|
ScoreBrackets.hasPendingEvent(EXP_PARAM_ACCESS) ||
|
|
ScoreBrackets.hasPendingEvent(EXP_POS_ACCESS) ||
|
|
ScoreBrackets.hasPendingEvent(GDS_GPR_LOCK)) {
|
|
Wait.ExpCnt = 0;
|
|
}
|
|
}
|
|
|
|
if (MI.isCall() && callWaitsOnFunctionEntry(MI)) {
|
|
// The function is going to insert a wait on everything in its prolog.
|
|
// This still needs to be careful if the call target is a load (e.g. a GOT
|
|
// load). We also need to check WAW depenancy with saved PC.
|
|
Wait = AMDGPU::Waitcnt();
|
|
|
|
int CallAddrOpIdx =
|
|
AMDGPU::getNamedOperandIdx(MI.getOpcode(), AMDGPU::OpName::src0);
|
|
|
|
if (MI.getOperand(CallAddrOpIdx).isReg()) {
|
|
RegInterval CallAddrOpInterval =
|
|
ScoreBrackets.getRegInterval(&MI, TII, MRI, TRI, CallAddrOpIdx);
|
|
|
|
for (int RegNo = CallAddrOpInterval.first;
|
|
RegNo < CallAddrOpInterval.second; ++RegNo)
|
|
ScoreBrackets.determineWait(
|
|
LGKM_CNT, ScoreBrackets.getRegScore(RegNo, LGKM_CNT), Wait);
|
|
|
|
int RtnAddrOpIdx =
|
|
AMDGPU::getNamedOperandIdx(MI.getOpcode(), AMDGPU::OpName::dst);
|
|
if (RtnAddrOpIdx != -1) {
|
|
RegInterval RtnAddrOpInterval =
|
|
ScoreBrackets.getRegInterval(&MI, TII, MRI, TRI, RtnAddrOpIdx);
|
|
|
|
for (int RegNo = RtnAddrOpInterval.first;
|
|
RegNo < RtnAddrOpInterval.second; ++RegNo)
|
|
ScoreBrackets.determineWait(
|
|
LGKM_CNT, ScoreBrackets.getRegScore(RegNo, LGKM_CNT), Wait);
|
|
}
|
|
}
|
|
} else {
|
|
// FIXME: Should not be relying on memoperands.
|
|
// Look at the source operands of every instruction to see if
|
|
// any of them results from a previous memory operation that affects
|
|
// its current usage. If so, an s_waitcnt instruction needs to be
|
|
// emitted.
|
|
// If the source operand was defined by a load, add the s_waitcnt
|
|
// instruction.
|
|
//
|
|
// Two cases are handled for destination operands:
|
|
// 1) If the destination operand was defined by a load, add the s_waitcnt
|
|
// instruction to guarantee the right WAW order.
|
|
// 2) If a destination operand that was used by a recent export/store ins,
|
|
// add s_waitcnt on exp_cnt to guarantee the WAR order.
|
|
for (const MachineMemOperand *Memop : MI.memoperands()) {
|
|
const Value *Ptr = Memop->getValue();
|
|
if (Memop->isStore() && SLoadAddresses.count(Ptr)) {
|
|
addWait(Wait, LGKM_CNT, 0);
|
|
if (PDT->dominates(MI.getParent(), SLoadAddresses.find(Ptr)->second))
|
|
SLoadAddresses.erase(Ptr);
|
|
}
|
|
unsigned AS = Memop->getAddrSpace();
|
|
if (AS != AMDGPUAS::LOCAL_ADDRESS)
|
|
continue;
|
|
unsigned RegNo = SQ_MAX_PGM_VGPRS + EXTRA_VGPR_LDS;
|
|
// VM_CNT is only relevant to vgpr or LDS.
|
|
ScoreBrackets.determineWait(
|
|
VM_CNT, ScoreBrackets.getRegScore(RegNo, VM_CNT), Wait);
|
|
if (Memop->isStore()) {
|
|
ScoreBrackets.determineWait(
|
|
EXP_CNT, ScoreBrackets.getRegScore(RegNo, EXP_CNT), Wait);
|
|
}
|
|
}
|
|
|
|
// Loop over use and def operands.
|
|
for (unsigned I = 0, E = MI.getNumOperands(); I != E; ++I) {
|
|
MachineOperand &Op = MI.getOperand(I);
|
|
if (!Op.isReg())
|
|
continue;
|
|
RegInterval Interval =
|
|
ScoreBrackets.getRegInterval(&MI, TII, MRI, TRI, I);
|
|
|
|
const bool IsVGPR = TRI->isVGPR(*MRI, Op.getReg());
|
|
for (int RegNo = Interval.first; RegNo < Interval.second; ++RegNo) {
|
|
if (IsVGPR) {
|
|
// RAW always needs an s_waitcnt. WAW needs an s_waitcnt unless the
|
|
// previous write and this write are the same type of VMEM
|
|
// instruction, in which case they're guaranteed to write their
|
|
// results in order anyway.
|
|
if (Op.isUse() || !SIInstrInfo::isVMEM(MI) ||
|
|
ScoreBrackets.hasOtherPendingVmemTypes(RegNo,
|
|
getVmemType(MI))) {
|
|
ScoreBrackets.determineWait(
|
|
VM_CNT, ScoreBrackets.getRegScore(RegNo, VM_CNT), Wait);
|
|
ScoreBrackets.clearVgprVmemTypes(RegNo);
|
|
}
|
|
if (Op.isDef()) {
|
|
ScoreBrackets.determineWait(
|
|
EXP_CNT, ScoreBrackets.getRegScore(RegNo, EXP_CNT), Wait);
|
|
}
|
|
}
|
|
ScoreBrackets.determineWait(
|
|
LGKM_CNT, ScoreBrackets.getRegScore(RegNo, LGKM_CNT), Wait);
|
|
}
|
|
}
|
|
}
|
|
}
|
|
|
|
// Check to see if this is an S_BARRIER, and if an implicit S_WAITCNT 0
|
|
// occurs before the instruction. Doing it here prevents any additional
|
|
// S_WAITCNTs from being emitted if the instruction was marked as
|
|
// requiring a WAITCNT beforehand.
|
|
if (MI.getOpcode() == AMDGPU::S_BARRIER &&
|
|
!ST->hasAutoWaitcntBeforeBarrier()) {
|
|
Wait = Wait.combined(AMDGPU::Waitcnt::allZero(ST->hasVscnt()));
|
|
}
|
|
|
|
// TODO: Remove this work-around, enable the assert for Bug 457939
|
|
// after fixing the scheduler. Also, the Shader Compiler code is
|
|
// independent of target.
|
|
if (readsVCCZ(MI) && ST->hasReadVCCZBug()) {
|
|
if (ScoreBrackets.getScoreLB(LGKM_CNT) <
|
|
ScoreBrackets.getScoreUB(LGKM_CNT) &&
|
|
ScoreBrackets.hasPendingEvent(SMEM_ACCESS)) {
|
|
Wait.LgkmCnt = 0;
|
|
}
|
|
}
|
|
|
|
// Early-out if no wait is indicated.
|
|
if (!ScoreBrackets.simplifyWaitcnt(Wait) && !IsForceEmitWaitcnt) {
|
|
bool Modified = false;
|
|
if (OldWaitcntInstr) {
|
|
for (auto II = OldWaitcntInstr->getIterator(), NextI = std::next(II);
|
|
&*II != &MI; II = NextI, ++NextI) {
|
|
if (II->isDebugInstr())
|
|
continue;
|
|
|
|
if (TrackedWaitcntSet.count(&*II)) {
|
|
TrackedWaitcntSet.erase(&*II);
|
|
II->eraseFromParent();
|
|
Modified = true;
|
|
} else if (II->getOpcode() == AMDGPU::S_WAITCNT) {
|
|
int64_t Imm = II->getOperand(0).getImm();
|
|
ScoreBrackets.applyWaitcnt(AMDGPU::decodeWaitcnt(IV, Imm));
|
|
} else {
|
|
assert(II->getOpcode() == AMDGPU::S_WAITCNT_VSCNT);
|
|
assert(II->getOperand(0).getReg() == AMDGPU::SGPR_NULL);
|
|
auto W = TII->getNamedOperand(*II, AMDGPU::OpName::simm16)->getImm();
|
|
ScoreBrackets.applyWaitcnt(AMDGPU::Waitcnt(~0u, ~0u, ~0u, W));
|
|
}
|
|
}
|
|
}
|
|
return Modified;
|
|
}
|
|
|
|
if (ForceEmitZeroWaitcnts)
|
|
Wait = AMDGPU::Waitcnt::allZero(ST->hasVscnt());
|
|
|
|
if (ForceEmitWaitcnt[VM_CNT])
|
|
Wait.VmCnt = 0;
|
|
if (ForceEmitWaitcnt[EXP_CNT])
|
|
Wait.ExpCnt = 0;
|
|
if (ForceEmitWaitcnt[LGKM_CNT])
|
|
Wait.LgkmCnt = 0;
|
|
if (ForceEmitWaitcnt[VS_CNT])
|
|
Wait.VsCnt = 0;
|
|
|
|
ScoreBrackets.applyWaitcnt(Wait);
|
|
|
|
AMDGPU::Waitcnt OldWait;
|
|
bool Modified = false;
|
|
|
|
if (OldWaitcntInstr) {
|
|
for (auto II = OldWaitcntInstr->getIterator(), NextI = std::next(II);
|
|
&*II != &MI; II = NextI, NextI++) {
|
|
if (II->isDebugInstr())
|
|
continue;
|
|
|
|
if (II->getOpcode() == AMDGPU::S_WAITCNT) {
|
|
unsigned IEnc = II->getOperand(0).getImm();
|
|
AMDGPU::Waitcnt IWait = AMDGPU::decodeWaitcnt(IV, IEnc);
|
|
OldWait = OldWait.combined(IWait);
|
|
if (!TrackedWaitcntSet.count(&*II))
|
|
Wait = Wait.combined(IWait);
|
|
unsigned NewEnc = AMDGPU::encodeWaitcnt(IV, Wait);
|
|
if (IEnc != NewEnc) {
|
|
II->getOperand(0).setImm(NewEnc);
|
|
Modified = true;
|
|
}
|
|
Wait.VmCnt = ~0u;
|
|
Wait.LgkmCnt = ~0u;
|
|
Wait.ExpCnt = ~0u;
|
|
} else {
|
|
assert(II->getOpcode() == AMDGPU::S_WAITCNT_VSCNT);
|
|
assert(II->getOperand(0).getReg() == AMDGPU::SGPR_NULL);
|
|
|
|
unsigned ICnt = TII->getNamedOperand(*II, AMDGPU::OpName::simm16)
|
|
->getImm();
|
|
OldWait.VsCnt = std::min(OldWait.VsCnt, ICnt);
|
|
if (!TrackedWaitcntSet.count(&*II))
|
|
Wait.VsCnt = std::min(Wait.VsCnt, ICnt);
|
|
if (Wait.VsCnt != ICnt) {
|
|
TII->getNamedOperand(*II, AMDGPU::OpName::simm16)->setImm(Wait.VsCnt);
|
|
Modified = true;
|
|
}
|
|
Wait.VsCnt = ~0u;
|
|
}
|
|
|
|
LLVM_DEBUG(dbgs() << "generateWaitcntInstBefore\n"
|
|
<< "Old Instr: " << MI
|
|
<< "New Instr: " << *II << '\n');
|
|
|
|
if (!Wait.hasWait())
|
|
return Modified;
|
|
}
|
|
}
|
|
|
|
if (Wait.VmCnt != ~0u || Wait.LgkmCnt != ~0u || Wait.ExpCnt != ~0u) {
|
|
unsigned Enc = AMDGPU::encodeWaitcnt(IV, Wait);
|
|
auto SWaitInst = BuildMI(*MI.getParent(), MI.getIterator(),
|
|
MI.getDebugLoc(), TII->get(AMDGPU::S_WAITCNT))
|
|
.addImm(Enc);
|
|
TrackedWaitcntSet.insert(SWaitInst);
|
|
Modified = true;
|
|
|
|
LLVM_DEBUG(dbgs() << "generateWaitcntInstBefore\n"
|
|
<< "Old Instr: " << MI
|
|
<< "New Instr: " << *SWaitInst << '\n');
|
|
}
|
|
|
|
if (Wait.VsCnt != ~0u) {
|
|
assert(ST->hasVscnt());
|
|
|
|
auto SWaitInst =
|
|
BuildMI(*MI.getParent(), MI.getIterator(), MI.getDebugLoc(),
|
|
TII->get(AMDGPU::S_WAITCNT_VSCNT))
|
|
.addReg(AMDGPU::SGPR_NULL, RegState::Undef)
|
|
.addImm(Wait.VsCnt);
|
|
TrackedWaitcntSet.insert(SWaitInst);
|
|
Modified = true;
|
|
|
|
LLVM_DEBUG(dbgs() << "generateWaitcntInstBefore\n"
|
|
<< "Old Instr: " << MI
|
|
<< "New Instr: " << *SWaitInst << '\n');
|
|
}
|
|
|
|
return Modified;
|
|
}
|
|
|
|
// This is a flat memory operation. Check to see if it has memory tokens other
|
|
// than LDS. Other address spaces supported by flat memory operations involve
|
|
// global memory.
|
|
bool SIInsertWaitcnts::mayAccessVMEMThroughFlat(const MachineInstr &MI) const {
|
|
assert(TII->isFLAT(MI));
|
|
|
|
// All flat instructions use the VMEM counter.
|
|
assert(TII->usesVM_CNT(MI));
|
|
|
|
// If there are no memory operands then conservatively assume the flat
|
|
// operation may access VMEM.
|
|
if (MI.memoperands_empty())
|
|
return true;
|
|
|
|
// See if any memory operand specifies an address space that involves VMEM.
|
|
// Flat operations only supported FLAT, LOCAL (LDS), or address spaces
|
|
// involving VMEM such as GLOBAL, CONSTANT, PRIVATE (SCRATCH), etc. The REGION
|
|
// (GDS) address space is not supported by flat operations. Therefore, simply
|
|
// return true unless only the LDS address space is found.
|
|
for (const MachineMemOperand *Memop : MI.memoperands()) {
|
|
unsigned AS = Memop->getAddrSpace();
|
|
assert(AS != AMDGPUAS::REGION_ADDRESS);
|
|
if (AS != AMDGPUAS::LOCAL_ADDRESS)
|
|
return true;
|
|
}
|
|
|
|
return false;
|
|
}
|
|
|
|
// This is a flat memory operation. Check to see if it has memory tokens for
|
|
// either LDS or FLAT.
|
|
bool SIInsertWaitcnts::mayAccessLDSThroughFlat(const MachineInstr &MI) const {
|
|
assert(TII->isFLAT(MI));
|
|
|
|
// Flat instruction such as SCRATCH and GLOBAL do not use the lgkm counter.
|
|
if (!TII->usesLGKM_CNT(MI))
|
|
return false;
|
|
|
|
// If there are no memory operands then conservatively assume the flat
|
|
// operation may access LDS.
|
|
if (MI.memoperands_empty())
|
|
return true;
|
|
|
|
// See if any memory operand specifies an address space that involves LDS.
|
|
for (const MachineMemOperand *Memop : MI.memoperands()) {
|
|
unsigned AS = Memop->getAddrSpace();
|
|
if (AS == AMDGPUAS::LOCAL_ADDRESS || AS == AMDGPUAS::FLAT_ADDRESS)
|
|
return true;
|
|
}
|
|
|
|
return false;
|
|
}
|
|
|
|
void SIInsertWaitcnts::updateEventWaitcntAfter(MachineInstr &Inst,
|
|
WaitcntBrackets *ScoreBrackets) {
|
|
// Now look at the instruction opcode. If it is a memory access
|
|
// instruction, update the upper-bound of the appropriate counter's
|
|
// bracket and the destination operand scores.
|
|
// TODO: Use the (TSFlags & SIInstrFlags::LGKM_CNT) property everywhere.
|
|
if (TII->isDS(Inst) && TII->usesLGKM_CNT(Inst)) {
|
|
if (TII->isAlwaysGDS(Inst.getOpcode()) ||
|
|
TII->hasModifiersSet(Inst, AMDGPU::OpName::gds)) {
|
|
ScoreBrackets->updateByEvent(TII, TRI, MRI, GDS_ACCESS, Inst);
|
|
ScoreBrackets->updateByEvent(TII, TRI, MRI, GDS_GPR_LOCK, Inst);
|
|
} else {
|
|
ScoreBrackets->updateByEvent(TII, TRI, MRI, LDS_ACCESS, Inst);
|
|
}
|
|
} else if (TII->isFLAT(Inst)) {
|
|
assert(Inst.mayLoadOrStore());
|
|
|
|
int FlatASCount = 0;
|
|
|
|
if (mayAccessVMEMThroughFlat(Inst)) {
|
|
++FlatASCount;
|
|
if (!ST->hasVscnt())
|
|
ScoreBrackets->updateByEvent(TII, TRI, MRI, VMEM_ACCESS, Inst);
|
|
else if (Inst.mayLoad() &&
|
|
AMDGPU::getAtomicRetOp(Inst.getOpcode()) == -1)
|
|
ScoreBrackets->updateByEvent(TII, TRI, MRI, VMEM_READ_ACCESS, Inst);
|
|
else
|
|
ScoreBrackets->updateByEvent(TII, TRI, MRI, VMEM_WRITE_ACCESS, Inst);
|
|
}
|
|
|
|
if (mayAccessLDSThroughFlat(Inst)) {
|
|
++FlatASCount;
|
|
ScoreBrackets->updateByEvent(TII, TRI, MRI, LDS_ACCESS, Inst);
|
|
}
|
|
|
|
// A Flat memory operation must access at least one address space.
|
|
assert(FlatASCount);
|
|
|
|
// This is a flat memory operation that access both VMEM and LDS, so note it
|
|
// - it will require that both the VM and LGKM be flushed to zero if it is
|
|
// pending when a VM or LGKM dependency occurs.
|
|
if (FlatASCount > 1)
|
|
ScoreBrackets->setPendingFlat();
|
|
} else if (SIInstrInfo::isVMEM(Inst) &&
|
|
// TODO: get a better carve out.
|
|
Inst.getOpcode() != AMDGPU::BUFFER_WBINVL1 &&
|
|
Inst.getOpcode() != AMDGPU::BUFFER_WBINVL1_SC &&
|
|
Inst.getOpcode() != AMDGPU::BUFFER_WBINVL1_VOL &&
|
|
Inst.getOpcode() != AMDGPU::BUFFER_GL0_INV &&
|
|
Inst.getOpcode() != AMDGPU::BUFFER_GL1_INV) {
|
|
if (!ST->hasVscnt())
|
|
ScoreBrackets->updateByEvent(TII, TRI, MRI, VMEM_ACCESS, Inst);
|
|
else if ((Inst.mayLoad() &&
|
|
AMDGPU::getAtomicRetOp(Inst.getOpcode()) == -1) ||
|
|
/* IMAGE_GET_RESINFO / IMAGE_GET_LOD */
|
|
(TII->isMIMG(Inst) && !Inst.mayLoad() && !Inst.mayStore()))
|
|
ScoreBrackets->updateByEvent(TII, TRI, MRI, VMEM_READ_ACCESS, Inst);
|
|
else if (Inst.mayStore())
|
|
ScoreBrackets->updateByEvent(TII, TRI, MRI, VMEM_WRITE_ACCESS, Inst);
|
|
|
|
if (ST->vmemWriteNeedsExpWaitcnt() &&
|
|
(Inst.mayStore() || AMDGPU::getAtomicNoRetOp(Inst.getOpcode()) != -1)) {
|
|
ScoreBrackets->updateByEvent(TII, TRI, MRI, VMW_GPR_LOCK, Inst);
|
|
}
|
|
} else if (TII->isSMRD(Inst)) {
|
|
ScoreBrackets->updateByEvent(TII, TRI, MRI, SMEM_ACCESS, Inst);
|
|
} else if (Inst.isCall()) {
|
|
if (callWaitsOnFunctionReturn(Inst)) {
|
|
// Act as a wait on everything
|
|
ScoreBrackets->applyWaitcnt(AMDGPU::Waitcnt::allZero(ST->hasVscnt()));
|
|
} else {
|
|
// May need to way wait for anything.
|
|
ScoreBrackets->applyWaitcnt(AMDGPU::Waitcnt());
|
|
}
|
|
} else if (SIInstrInfo::isEXP(Inst)) {
|
|
unsigned Imm = TII->getNamedOperand(Inst, AMDGPU::OpName::tgt)->getImm();
|
|
if (Imm >= AMDGPU::Exp::ET_PARAM0 && Imm <= AMDGPU::Exp::ET_PARAM31)
|
|
ScoreBrackets->updateByEvent(TII, TRI, MRI, EXP_PARAM_ACCESS, Inst);
|
|
else if (Imm >= AMDGPU::Exp::ET_POS0 && Imm <= AMDGPU::Exp::ET_POS_LAST)
|
|
ScoreBrackets->updateByEvent(TII, TRI, MRI, EXP_POS_ACCESS, Inst);
|
|
else
|
|
ScoreBrackets->updateByEvent(TII, TRI, MRI, EXP_GPR_LOCK, Inst);
|
|
} else {
|
|
switch (Inst.getOpcode()) {
|
|
case AMDGPU::S_SENDMSG:
|
|
case AMDGPU::S_SENDMSGHALT:
|
|
ScoreBrackets->updateByEvent(TII, TRI, MRI, SQ_MESSAGE, Inst);
|
|
break;
|
|
case AMDGPU::S_MEMTIME:
|
|
case AMDGPU::S_MEMREALTIME:
|
|
ScoreBrackets->updateByEvent(TII, TRI, MRI, SMEM_ACCESS, Inst);
|
|
break;
|
|
}
|
|
}
|
|
}
|
|
|
|
bool WaitcntBrackets::mergeScore(const MergeInfo &M, unsigned &Score,
|
|
unsigned OtherScore) {
|
|
unsigned MyShifted = Score <= M.OldLB ? 0 : Score + M.MyShift;
|
|
unsigned OtherShifted =
|
|
OtherScore <= M.OtherLB ? 0 : OtherScore + M.OtherShift;
|
|
Score = std::max(MyShifted, OtherShifted);
|
|
return OtherShifted > MyShifted;
|
|
}
|
|
|
|
/// Merge the pending events and associater score brackets of \p Other into
|
|
/// this brackets status.
|
|
///
|
|
/// Returns whether the merge resulted in a change that requires tighter waits
|
|
/// (i.e. the merged brackets strictly dominate the original brackets).
|
|
bool WaitcntBrackets::merge(const WaitcntBrackets &Other) {
|
|
bool StrictDom = false;
|
|
|
|
VgprUB = std::max(VgprUB, Other.VgprUB);
|
|
SgprUB = std::max(SgprUB, Other.SgprUB);
|
|
|
|
for (auto T : inst_counter_types()) {
|
|
// Merge event flags for this counter
|
|
const bool OldOutOfOrder = counterOutOfOrder(T);
|
|
const unsigned OldEvents = PendingEvents & WaitEventMaskForInst[T];
|
|
const unsigned OtherEvents = Other.PendingEvents & WaitEventMaskForInst[T];
|
|
if (OtherEvents & ~OldEvents)
|
|
StrictDom = true;
|
|
PendingEvents |= OtherEvents;
|
|
|
|
// Merge scores for this counter
|
|
const unsigned MyPending = ScoreUBs[T] - ScoreLBs[T];
|
|
const unsigned OtherPending = Other.ScoreUBs[T] - Other.ScoreLBs[T];
|
|
const unsigned NewUB = ScoreLBs[T] + std::max(MyPending, OtherPending);
|
|
if (NewUB < ScoreLBs[T])
|
|
report_fatal_error("waitcnt score overflow");
|
|
|
|
MergeInfo M;
|
|
M.OldLB = ScoreLBs[T];
|
|
M.OtherLB = Other.ScoreLBs[T];
|
|
M.MyShift = NewUB - ScoreUBs[T];
|
|
M.OtherShift = NewUB - Other.ScoreUBs[T];
|
|
|
|
ScoreUBs[T] = NewUB;
|
|
|
|
StrictDom |= mergeScore(M, LastFlat[T], Other.LastFlat[T]);
|
|
|
|
bool RegStrictDom = false;
|
|
for (int J = 0; J <= VgprUB; J++) {
|
|
RegStrictDom |= mergeScore(M, VgprScores[T][J], Other.VgprScores[T][J]);
|
|
}
|
|
|
|
if (T == VM_CNT) {
|
|
for (int J = 0; J <= VgprUB; J++) {
|
|
unsigned char NewVmemTypes = VgprVmemTypes[J] | Other.VgprVmemTypes[J];
|
|
RegStrictDom |= NewVmemTypes != VgprVmemTypes[J];
|
|
VgprVmemTypes[J] = NewVmemTypes;
|
|
}
|
|
}
|
|
|
|
if (T == LGKM_CNT) {
|
|
for (int J = 0; J <= SgprUB; J++) {
|
|
RegStrictDom |= mergeScore(M, SgprScores[J], Other.SgprScores[J]);
|
|
}
|
|
}
|
|
|
|
if (RegStrictDom && !OldOutOfOrder)
|
|
StrictDom = true;
|
|
}
|
|
|
|
return StrictDom;
|
|
}
|
|
|
|
// Generate s_waitcnt instructions where needed.
|
|
bool SIInsertWaitcnts::insertWaitcntInBlock(MachineFunction &MF,
|
|
MachineBasicBlock &Block,
|
|
WaitcntBrackets &ScoreBrackets) {
|
|
bool Modified = false;
|
|
|
|
LLVM_DEBUG({
|
|
dbgs() << "*** Block" << Block.getNumber() << " ***";
|
|
ScoreBrackets.dump();
|
|
});
|
|
|
|
// Track the correctness of vccz through this basic block. There are two
|
|
// reasons why it might be incorrect; see ST->hasReadVCCZBug() and
|
|
// ST->partialVCCWritesUpdateVCCZ().
|
|
bool VCCZCorrect = true;
|
|
if (ST->hasReadVCCZBug()) {
|
|
// vccz could be incorrect at a basic block boundary if a predecessor wrote
|
|
// to vcc and then issued an smem load.
|
|
VCCZCorrect = false;
|
|
} else if (!ST->partialVCCWritesUpdateVCCZ()) {
|
|
// vccz could be incorrect at a basic block boundary if a predecessor wrote
|
|
// to vcc_lo or vcc_hi.
|
|
VCCZCorrect = false;
|
|
}
|
|
|
|
// Walk over the instructions.
|
|
MachineInstr *OldWaitcntInstr = nullptr;
|
|
|
|
for (MachineBasicBlock::instr_iterator Iter = Block.instr_begin(),
|
|
E = Block.instr_end();
|
|
Iter != E;) {
|
|
MachineInstr &Inst = *Iter;
|
|
|
|
// Track pre-existing waitcnts from earlier iterations.
|
|
if (Inst.getOpcode() == AMDGPU::S_WAITCNT ||
|
|
(Inst.getOpcode() == AMDGPU::S_WAITCNT_VSCNT &&
|
|
Inst.getOperand(0).isReg() &&
|
|
Inst.getOperand(0).getReg() == AMDGPU::SGPR_NULL)) {
|
|
if (!OldWaitcntInstr)
|
|
OldWaitcntInstr = &Inst;
|
|
++Iter;
|
|
continue;
|
|
}
|
|
|
|
// Generate an s_waitcnt instruction to be placed before Inst, if needed.
|
|
Modified |= generateWaitcntInstBefore(Inst, ScoreBrackets, OldWaitcntInstr);
|
|
OldWaitcntInstr = nullptr;
|
|
|
|
// Restore vccz if it's not known to be correct already.
|
|
bool RestoreVCCZ = !VCCZCorrect && readsVCCZ(Inst);
|
|
|
|
// Don't examine operands unless we need to track vccz correctness.
|
|
if (ST->hasReadVCCZBug() || !ST->partialVCCWritesUpdateVCCZ()) {
|
|
if (Inst.definesRegister(AMDGPU::VCC_LO) ||
|
|
Inst.definesRegister(AMDGPU::VCC_HI)) {
|
|
// Up to gfx9, writes to vcc_lo and vcc_hi don't update vccz.
|
|
if (!ST->partialVCCWritesUpdateVCCZ())
|
|
VCCZCorrect = false;
|
|
} else if (Inst.definesRegister(AMDGPU::VCC)) {
|
|
// There is a hardware bug on CI/SI where SMRD instruction may corrupt
|
|
// vccz bit, so when we detect that an instruction may read from a
|
|
// corrupt vccz bit, we need to:
|
|
// 1. Insert s_waitcnt lgkm(0) to wait for all outstanding SMRD
|
|
// operations to complete.
|
|
// 2. Restore the correct value of vccz by writing the current value
|
|
// of vcc back to vcc.
|
|
if (ST->hasReadVCCZBug() &&
|
|
ScoreBrackets.getScoreLB(LGKM_CNT) <
|
|
ScoreBrackets.getScoreUB(LGKM_CNT) &&
|
|
ScoreBrackets.hasPendingEvent(SMEM_ACCESS)) {
|
|
// Writes to vcc while there's an outstanding smem read may get
|
|
// clobbered as soon as any read completes.
|
|
VCCZCorrect = false;
|
|
} else {
|
|
// Writes to vcc will fix any incorrect value in vccz.
|
|
VCCZCorrect = true;
|
|
}
|
|
}
|
|
}
|
|
|
|
if (TII->isSMRD(Inst)) {
|
|
for (const MachineMemOperand *Memop : Inst.memoperands()) {
|
|
const Value *Ptr = Memop->getValue();
|
|
SLoadAddresses.insert(std::make_pair(Ptr, Inst.getParent()));
|
|
}
|
|
if (ST->hasReadVCCZBug()) {
|
|
// This smem read could complete and clobber vccz at any time.
|
|
VCCZCorrect = false;
|
|
}
|
|
}
|
|
|
|
updateEventWaitcntAfter(Inst, &ScoreBrackets);
|
|
|
|
#if 0 // TODO: implement resource type check controlled by options with ub = LB.
|
|
// If this instruction generates a S_SETVSKIP because it is an
|
|
// indexed resource, and we are on Tahiti, then it will also force
|
|
// an S_WAITCNT vmcnt(0)
|
|
if (RequireCheckResourceType(Inst, context)) {
|
|
// Force the score to as if an S_WAITCNT vmcnt(0) is emitted.
|
|
ScoreBrackets->setScoreLB(VM_CNT,
|
|
ScoreBrackets->getScoreUB(VM_CNT));
|
|
}
|
|
#endif
|
|
|
|
LLVM_DEBUG({
|
|
Inst.print(dbgs());
|
|
ScoreBrackets.dump();
|
|
});
|
|
|
|
// TODO: Remove this work-around after fixing the scheduler and enable the
|
|
// assert above.
|
|
if (RestoreVCCZ) {
|
|
// Restore the vccz bit. Any time a value is written to vcc, the vcc
|
|
// bit is updated, so we can restore the bit by reading the value of
|
|
// vcc and then writing it back to the register.
|
|
BuildMI(Block, Inst, Inst.getDebugLoc(),
|
|
TII->get(ST->isWave32() ? AMDGPU::S_MOV_B32 : AMDGPU::S_MOV_B64),
|
|
TRI->getVCC())
|
|
.addReg(TRI->getVCC());
|
|
VCCZCorrect = true;
|
|
Modified = true;
|
|
}
|
|
|
|
++Iter;
|
|
}
|
|
|
|
return Modified;
|
|
}
|
|
|
|
bool SIInsertWaitcnts::runOnMachineFunction(MachineFunction &MF) {
|
|
ST = &MF.getSubtarget<GCNSubtarget>();
|
|
TII = ST->getInstrInfo();
|
|
TRI = &TII->getRegisterInfo();
|
|
MRI = &MF.getRegInfo();
|
|
IV = AMDGPU::getIsaVersion(ST->getCPU());
|
|
const SIMachineFunctionInfo *MFI = MF.getInfo<SIMachineFunctionInfo>();
|
|
PDT = &getAnalysis<MachinePostDominatorTree>();
|
|
|
|
ForceEmitZeroWaitcnts = ForceEmitZeroFlag;
|
|
for (auto T : inst_counter_types())
|
|
ForceEmitWaitcnt[T] = false;
|
|
|
|
HardwareLimits.VmcntMax = AMDGPU::getVmcntBitMask(IV);
|
|
HardwareLimits.ExpcntMax = AMDGPU::getExpcntBitMask(IV);
|
|
HardwareLimits.LgkmcntMax = AMDGPU::getLgkmcntBitMask(IV);
|
|
HardwareLimits.VscntMax = ST->hasVscnt() ? 63 : 0;
|
|
|
|
unsigned NumVGPRsMax = ST->getAddressableNumVGPRs();
|
|
unsigned NumSGPRsMax = ST->getAddressableNumSGPRs();
|
|
assert(NumVGPRsMax <= SQ_MAX_PGM_VGPRS);
|
|
assert(NumSGPRsMax <= SQ_MAX_PGM_SGPRS);
|
|
|
|
RegisterEncoding.VGPR0 = TRI->getEncodingValue(AMDGPU::VGPR0);
|
|
RegisterEncoding.VGPRL = RegisterEncoding.VGPR0 + NumVGPRsMax - 1;
|
|
RegisterEncoding.SGPR0 = TRI->getEncodingValue(AMDGPU::SGPR0);
|
|
RegisterEncoding.SGPRL = RegisterEncoding.SGPR0 + NumSGPRsMax - 1;
|
|
|
|
TrackedWaitcntSet.clear();
|
|
BlockInfos.clear();
|
|
|
|
// Keep iterating over the blocks in reverse post order, inserting and
|
|
// updating s_waitcnt where needed, until a fix point is reached.
|
|
for (auto *MBB : ReversePostOrderTraversal<MachineFunction *>(&MF))
|
|
BlockInfos.insert({MBB, BlockInfo(MBB)});
|
|
|
|
std::unique_ptr<WaitcntBrackets> Brackets;
|
|
bool Modified = false;
|
|
bool Repeat;
|
|
do {
|
|
Repeat = false;
|
|
|
|
for (auto BII = BlockInfos.begin(), BIE = BlockInfos.end(); BII != BIE;
|
|
++BII) {
|
|
BlockInfo &BI = BII->second;
|
|
if (!BI.Dirty)
|
|
continue;
|
|
|
|
if (BI.Incoming) {
|
|
if (!Brackets)
|
|
Brackets = std::make_unique<WaitcntBrackets>(*BI.Incoming);
|
|
else
|
|
*Brackets = *BI.Incoming;
|
|
} else {
|
|
if (!Brackets)
|
|
Brackets = std::make_unique<WaitcntBrackets>(ST);
|
|
else
|
|
*Brackets = WaitcntBrackets(ST);
|
|
}
|
|
|
|
Modified |= insertWaitcntInBlock(MF, *BI.MBB, *Brackets);
|
|
BI.Dirty = false;
|
|
|
|
if (Brackets->hasPending()) {
|
|
BlockInfo *MoveBracketsToSucc = nullptr;
|
|
for (MachineBasicBlock *Succ : BI.MBB->successors()) {
|
|
auto SuccBII = BlockInfos.find(Succ);
|
|
BlockInfo &SuccBI = SuccBII->second;
|
|
if (!SuccBI.Incoming) {
|
|
SuccBI.Dirty = true;
|
|
if (SuccBII <= BII)
|
|
Repeat = true;
|
|
if (!MoveBracketsToSucc) {
|
|
MoveBracketsToSucc = &SuccBI;
|
|
} else {
|
|
SuccBI.Incoming = std::make_unique<WaitcntBrackets>(*Brackets);
|
|
}
|
|
} else if (SuccBI.Incoming->merge(*Brackets)) {
|
|
SuccBI.Dirty = true;
|
|
if (SuccBII <= BII)
|
|
Repeat = true;
|
|
}
|
|
}
|
|
if (MoveBracketsToSucc)
|
|
MoveBracketsToSucc->Incoming = std::move(Brackets);
|
|
}
|
|
}
|
|
} while (Repeat);
|
|
|
|
SmallVector<MachineBasicBlock *, 4> EndPgmBlocks;
|
|
|
|
bool HaveScalarStores = false;
|
|
|
|
for (MachineFunction::iterator BI = MF.begin(), BE = MF.end(); BI != BE;
|
|
++BI) {
|
|
MachineBasicBlock &MBB = *BI;
|
|
|
|
for (MachineBasicBlock::iterator I = MBB.begin(), E = MBB.end(); I != E;
|
|
++I) {
|
|
if (!HaveScalarStores && TII->isScalarStore(*I))
|
|
HaveScalarStores = true;
|
|
|
|
if (I->getOpcode() == AMDGPU::S_ENDPGM ||
|
|
I->getOpcode() == AMDGPU::SI_RETURN_TO_EPILOG)
|
|
EndPgmBlocks.push_back(&MBB);
|
|
}
|
|
}
|
|
|
|
if (HaveScalarStores) {
|
|
// If scalar writes are used, the cache must be flushed or else the next
|
|
// wave to reuse the same scratch memory can be clobbered.
|
|
//
|
|
// Insert s_dcache_wb at wave termination points if there were any scalar
|
|
// stores, and only if the cache hasn't already been flushed. This could be
|
|
// improved by looking across blocks for flushes in postdominating blocks
|
|
// from the stores but an explicitly requested flush is probably very rare.
|
|
for (MachineBasicBlock *MBB : EndPgmBlocks) {
|
|
bool SeenDCacheWB = false;
|
|
|
|
for (MachineBasicBlock::iterator I = MBB->begin(), E = MBB->end(); I != E;
|
|
++I) {
|
|
if (I->getOpcode() == AMDGPU::S_DCACHE_WB)
|
|
SeenDCacheWB = true;
|
|
else if (TII->isScalarStore(*I))
|
|
SeenDCacheWB = false;
|
|
|
|
// FIXME: It would be better to insert this before a waitcnt if any.
|
|
if ((I->getOpcode() == AMDGPU::S_ENDPGM ||
|
|
I->getOpcode() == AMDGPU::SI_RETURN_TO_EPILOG) &&
|
|
!SeenDCacheWB) {
|
|
Modified = true;
|
|
BuildMI(*MBB, I, I->getDebugLoc(), TII->get(AMDGPU::S_DCACHE_WB));
|
|
}
|
|
}
|
|
}
|
|
}
|
|
|
|
if (!MFI->isEntryFunction()) {
|
|
// Wait for any outstanding memory operations that the input registers may
|
|
// depend on. We can't track them and it's better to the wait after the
|
|
// costly call sequence.
|
|
|
|
// TODO: Could insert earlier and schedule more liberally with operations
|
|
// that only use caller preserved registers.
|
|
MachineBasicBlock &EntryBB = MF.front();
|
|
MachineBasicBlock::iterator I = EntryBB.begin();
|
|
for (MachineBasicBlock::iterator E = EntryBB.end();
|
|
I != E && (I->isPHI() || I->isMetaInstruction()); ++I)
|
|
;
|
|
BuildMI(EntryBB, I, DebugLoc(), TII->get(AMDGPU::S_WAITCNT)).addImm(0);
|
|
if (ST->hasVscnt())
|
|
BuildMI(EntryBB, I, DebugLoc(), TII->get(AMDGPU::S_WAITCNT_VSCNT))
|
|
.addReg(AMDGPU::SGPR_NULL, RegState::Undef)
|
|
.addImm(0);
|
|
|
|
Modified = true;
|
|
}
|
|
|
|
return Modified;
|
|
}
|