[llvm] r305681 - Revert r305677 [CodeGen] Add generic MacroFusion pass.
Florian Hahn via llvm-commits
llvm-commits at lists.llvm.org
Mon Jun 19 04:26:15 PDT 2017
Author: fhahn
Date: Mon Jun 19 06:26:15 2017
New Revision: 305681
URL: http://llvm.org/viewvc/llvm-project?rev=305681&view=rev
Log:
Revert r305677 [CodeGen] Add generic MacroFusion pass.
This causes Windows buildbot failures do an ambiguous call.
Removed:
llvm/trunk/include/llvm/CodeGen/MacroFusion.h
llvm/trunk/lib/CodeGen/MacroFusion.cpp
Modified:
llvm/trunk/lib/CodeGen/CMakeLists.txt
llvm/trunk/lib/Target/AArch64/AArch64MacroFusion.cpp
llvm/trunk/lib/Target/AArch64/AArch64MacroFusion.h
llvm/trunk/lib/Target/X86/X86MacroFusion.cpp
llvm/trunk/lib/Target/X86/X86MacroFusion.h
Removed: llvm/trunk/include/llvm/CodeGen/MacroFusion.h
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/include/llvm/CodeGen/MacroFusion.h?rev=305680&view=auto
==============================================================================
--- llvm/trunk/include/llvm/CodeGen/MacroFusion.h (original)
+++ llvm/trunk/include/llvm/CodeGen/MacroFusion.h (removed)
@@ -1,41 +0,0 @@
-//===- MacroFusion.h - Macro Fusion ------------------------===//
-//
-// The LLVM Compiler Infrastructure
-//
-// This file is distributed under the University of Illinois Open Source
-// License. See LICENSE.TXT for details.
-//
-//===----------------------------------------------------------------------===//
-//
-/// \file This file contains the definition of the DAG scheduling mutation to
-/// pair instructions back to back.
-//
-//===----------------------------------------------------------------------===//
-
-#include <functional>
-#include "llvm/Target/TargetInstrInfo.h"
-#include "llvm/CodeGen/MachineScheduler.h"
-
-namespace llvm {
-
-/// \brief Check if the instr pair, FirstMI and SecondMI, should be fused
-/// together. Given SecondMI, when FirstMI is unspecified, then check if
-/// SecondMI may be part of a fused pair at all.
-typedef std::function<bool(const TargetInstrInfo &TII,
- const TargetSubtargetInfo &TSI,
- const MachineInstr *FirstMI,
- const MachineInstr &SecondMI)> ShouldSchedulePredTy;
-
-/// \brief Create a DAG scheduling mutation to pair instructions back to back
-/// for instructions that benefit according to the target-specific
-/// shouldScheduleAdjacent predicate function.
-std::unique_ptr<ScheduleDAGMutation>
-createMacroFusionDAGMutation(ShouldSchedulePredTy shouldScheduleAdjacent);
-
-/// \brief Create a DAG scheduling mutation to pair branch instructions with one
-/// of their predecessors back to back for instructions that benefit according
-/// to the target-specific shouldScheduleAdjacent predicate function.
-std::unique_ptr<ScheduleDAGMutation>
-createBranchMacroFusionDAGMutation(ShouldSchedulePredTy shouldScheduleAdjacent);
-
-} // end namespace llvm
Modified: llvm/trunk/lib/CodeGen/CMakeLists.txt
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/CodeGen/CMakeLists.txt?rev=305681&r1=305680&r2=305681&view=diff
==============================================================================
--- llvm/trunk/lib/CodeGen/CMakeLists.txt (original)
+++ llvm/trunk/lib/CodeGen/CMakeLists.txt Mon Jun 19 06:26:15 2017
@@ -92,7 +92,6 @@ add_llvm_library(LLVMCodeGen
PatchableFunction.cpp
MIRPrinter.cpp
MIRPrintingPass.cpp
- MacroFusion.cpp
OptimizePHIs.cpp
ParallelCG.cpp
PeepholeOptimizer.cpp
Removed: llvm/trunk/lib/CodeGen/MacroFusion.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/CodeGen/MacroFusion.cpp?rev=305680&view=auto
==============================================================================
--- llvm/trunk/lib/CodeGen/MacroFusion.cpp (original)
+++ llvm/trunk/lib/CodeGen/MacroFusion.cpp (removed)
@@ -1,150 +0,0 @@
-//===- MacroFusion.cpp - Macro Fusion ----------------------===//
-//
-// The LLVM Compiler Infrastructure
-//
-// This file is distributed under the University of Illinois Open Source
-// License. See LICENSE.TXT for details.
-//
-//===----------------------------------------------------------------------===//
-//
-/// \file This file contains the implementation of the DAG scheduling mutation
-/// to pair instructions back to back.
-//
-//===----------------------------------------------------------------------===//
-
-#include "llvm/CodeGen/MacroFusion.h"
-#include "llvm/ADT/Statistic.h"
-#include "llvm/Support/CommandLine.h"
-#include "llvm/Target/TargetInstrInfo.h"
-
-#define DEBUG_TYPE "misched"
-
-STATISTIC(NumFused, "Number of instr pairs fused");
-
-using namespace llvm;
-
-static cl::opt<bool> EnableMacroFusion("misched-fusion", cl::Hidden,
- cl::desc("Enable scheduling for macro fusion."), cl::init(true));
-
-namespace {
-
-static void fuseInstructionPair(ScheduleDAGMI &DAG, SUnit &FirstSU,
- SUnit &SecondSU) {
- // Create a single weak edge between the adjacent instrs. The only effect is
- // to cause bottom-up scheduling to heavily prioritize the clustered instrs.
- DAG.addEdge(&SecondSU, SDep(&FirstSU, SDep::Cluster));
-
- // Adjust the latency between the anchor instr and its
- // predecessors.
- for (SDep &IDep : SecondSU.Preds)
- if (IDep.getSUnit() == &FirstSU)
- IDep.setLatency(0);
-
- // Adjust the latency between the dependent instr and its
- // predecessors.
- for (SDep &IDep : FirstSU.Succs)
- if (IDep.getSUnit() == &SecondSU)
- IDep.setLatency(0);
-
- DEBUG(dbgs() << DAG.MF.getName() << "(): Macro fuse ";
- FirstSU.print(dbgs(), &DAG); dbgs() << " - ";
- SecondSU.print(dbgs(), &DAG); dbgs() << " / ";
- dbgs() << DAG.TII->getName(FirstSU.getInstr()->getOpcode()) << " - " <<
- DAG.TII->getName(SecondSU.getInstr()->getOpcode()) << '\n'; );
-
- if (&SecondSU != &DAG.ExitSU)
- // Make instructions dependent on FirstSU also dependent on SecondSU to
- // prevent them from being scheduled between FirstSU and and SecondSU.
- for (const SDep &SI : FirstSU.Succs) {
- if (SI.getSUnit() == &SecondSU)
- continue;
- DEBUG(dbgs() << " Copy Succ ";
- SI.getSUnit()->print(dbgs(), &DAG); dbgs() << '\n';);
- DAG.addEdge(SI.getSUnit(), SDep(&SecondSU, SDep::Artificial));
- }
-
- ++NumFused;
-}
-
-
-/// \brief Post-process the DAG to create cluster edges between instrs that may
-/// be fused by the processor into a single operation.
-class MacroFusion : public ScheduleDAGMutation {
- ShouldSchedulePredTy shouldScheduleAdjacent;
- bool FuseBlock;
- bool scheduleAdjacentImpl(ScheduleDAGMI &DAG, SUnit &AnchorSU);
-
-public:
- MacroFusion(ShouldSchedulePredTy shouldScheduleAdjacent, bool FuseBlock)
- : shouldScheduleAdjacent(shouldScheduleAdjacent), FuseBlock(FuseBlock) {}
-
- void apply(ScheduleDAGInstrs *DAGInstrs) override;
-};
-
-void MacroFusion::apply(ScheduleDAGInstrs *DAGInstrs) {
- ScheduleDAGMI *DAG = static_cast<ScheduleDAGMI*>(DAGInstrs);
-
- if (FuseBlock)
- // For each of the SUnits in the scheduling block, try to fuse the instr in
- // it with one in its predecessors.
- for (SUnit &ISU : DAG->SUnits)
- scheduleAdjacentImpl(*DAG, ISU);
-
- if (DAG->ExitSU.getInstr())
- // Try to fuse the instr in the ExitSU with one in its predecessors.
- scheduleAdjacentImpl(*DAG, DAG->ExitSU);
-}
-
-/// \brief Implement the fusion of instr pairs in the scheduling DAG,
-/// anchored at the instr in AnchorSU..
-bool MacroFusion::scheduleAdjacentImpl(ScheduleDAGMI &DAG, SUnit &AnchorSU) {
- const MachineInstr &AnchorMI = *AnchorSU.getInstr();
- const TargetInstrInfo &TII = *DAG.TII;
- const TargetSubtargetInfo &ST = DAG.MF.getSubtarget();
-
- // Check if the anchor instr may be fused.
- if (!shouldScheduleAdjacent(TII, ST, nullptr, AnchorMI))
- return false;
-
- // Explorer for fusion candidates among the dependencies of the anchor instr.
- for (SDep &Dep : AnchorSU.Preds) {
- // Ignore dependencies that don't enforce ordering.
- if (Dep.getKind() == SDep::Anti || Dep.getKind() == SDep::Output ||
- Dep.isWeak())
- continue;
-
- SUnit &DepSU = *Dep.getSUnit();
- if (DepSU.isBoundaryNode())
- continue;
-
- const MachineInstr *DepMI = DepSU.getInstr();
- if (!shouldScheduleAdjacent(TII, ST, DepMI, AnchorMI))
- continue;
-
- fuseInstructionPair(DAG, DepSU, AnchorSU);
- return true;
- }
-
- return false;
-}
-
-} // end anonymous namespace
-
-
-namespace llvm {
-
-std::unique_ptr<ScheduleDAGMutation>
-createMacroFusionDAGMutation(ShouldSchedulePredTy shouldScheduleAdjacent) {
- if(EnableMacroFusion)
- return make_unique<MacroFusion>(shouldScheduleAdjacent, true);
- return nullptr;
-}
-
-std::unique_ptr<ScheduleDAGMutation>
-createBranchMacroFusionDAGMutation(ShouldSchedulePredTy shouldScheduleAdjacent) {
- if(EnableMacroFusion)
- return make_unique<MacroFusion>(shouldScheduleAdjacent, false);
- return nullptr;
-}
-
-} // end namespace llvm
Modified: llvm/trunk/lib/Target/AArch64/AArch64MacroFusion.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Target/AArch64/AArch64MacroFusion.cpp?rev=305681&r1=305680&r2=305681&view=diff
==============================================================================
--- llvm/trunk/lib/Target/AArch64/AArch64MacroFusion.cpp (original)
+++ llvm/trunk/lib/Target/AArch64/AArch64MacroFusion.cpp Mon Jun 19 06:26:15 2017
@@ -7,27 +7,37 @@
//
//===----------------------------------------------------------------------===//
//
-/// \file This file contains the AArch64 implementation of the DAG scheduling
-/// mutation to pair instructions back to back.
+// \file This file contains the AArch64 implementation of the DAG scheduling mutation
+// to pair instructions back to back.
//
//===----------------------------------------------------------------------===//
#include "AArch64MacroFusion.h"
#include "AArch64Subtarget.h"
-#include "llvm/CodeGen/MacroFusion.h"
+#include "llvm/ADT/Statistic.h"
+#include "llvm/Support/CommandLine.h"
#include "llvm/Target/TargetInstrInfo.h"
+#define DEBUG_TYPE "misched"
+
+STATISTIC(NumFused, "Number of instr pairs fused");
+
using namespace llvm;
+static cl::opt<bool> EnableMacroFusion("aarch64-misched-fusion", cl::Hidden,
+ cl::desc("Enable scheduling for macro fusion."), cl::init(true));
+
namespace {
-/// \brief Check if the instr pair, FirstMI and SecondMI, should be fused
-/// together. Given SecondMI, when FirstMI is unspecified, then check if
-/// SecondMI may be part of a fused pair at all.
+/// \brief Verify that the instr pair, FirstMI and SecondMI, should be fused
+/// together. Given an anchor instr, when the other instr is unspecified, then
+/// check if the anchor instr may be part of a fused pair at all.
static bool shouldScheduleAdjacent(const TargetInstrInfo &TII,
const TargetSubtargetInfo &TSI,
const MachineInstr *FirstMI,
- const MachineInstr &SecondMI) {
+ const MachineInstr *SecondMI) {
+ assert((FirstMI || SecondMI) && "At least one instr must be specified");
+
const AArch64InstrInfo &II = static_cast<const AArch64InstrInfo&>(TII);
const AArch64Subtarget &ST = static_cast<const AArch64Subtarget&>(TSI);
@@ -35,7 +45,9 @@ static bool shouldScheduleAdjacent(const
unsigned FirstOpcode =
FirstMI ? FirstMI->getOpcode()
: static_cast<unsigned>(AArch64::INSTRUCTION_LIST_END);
- unsigned SecondOpcode = SecondMI.getOpcode();
+ unsigned SecondOpcode =
+ SecondMI ? SecondMI->getOpcode()
+ : static_cast<unsigned>(AArch64::INSTRUCTION_LIST_END);
if (ST.hasArithmeticBccFusion())
// Fuse CMN, CMP, TST followed by Bcc.
@@ -116,49 +128,158 @@ static bool shouldScheduleAdjacent(const
if (ST.hasFuseAES())
// Fuse AES crypto operations.
- switch(SecondOpcode) {
+ switch(FirstOpcode) {
// AES encode.
- case AArch64::AESMCrr :
- return FirstOpcode == AArch64::AESErr ||
- FirstOpcode == AArch64::INSTRUCTION_LIST_END;
+ case AArch64::AESErr:
+ return SecondOpcode == AArch64::AESMCrr ||
+ SecondOpcode == AArch64::INSTRUCTION_LIST_END;
// AES decode.
- case AArch64::AESIMCrr:
- return FirstOpcode == AArch64::AESDrr ||
- FirstOpcode == AArch64::INSTRUCTION_LIST_END;
+ case AArch64::AESDrr:
+ return SecondOpcode == AArch64::AESIMCrr ||
+ SecondOpcode == AArch64::INSTRUCTION_LIST_END;
}
if (ST.hasFuseLiterals())
// Fuse literal generation operations.
- switch (SecondOpcode) {
+ switch (FirstOpcode) {
// PC relative address.
- case AArch64::ADDXri:
- return FirstOpcode == AArch64::ADRP ||
- FirstOpcode == AArch64::INSTRUCTION_LIST_END;
+ case AArch64::ADRP:
+ return SecondOpcode == AArch64::ADDXri ||
+ SecondOpcode == AArch64::INSTRUCTION_LIST_END;
// 32 bit immediate.
- case AArch64::MOVKWi:
- return (FirstOpcode == AArch64::MOVZWi &&
- SecondMI.getOperand(3).getImm() == 16) ||
- FirstOpcode == AArch64::INSTRUCTION_LIST_END;
- // Lower and upper half of 64 bit immediate.
+ case AArch64::MOVZWi:
+ return (SecondOpcode == AArch64::MOVKWi &&
+ SecondMI->getOperand(3).getImm() == 16) ||
+ SecondOpcode == AArch64::INSTRUCTION_LIST_END;
+ // Lower half of 64 bit immediate.
+ case AArch64::MOVZXi:
+ return (SecondOpcode == AArch64::MOVKXi &&
+ SecondMI->getOperand(3).getImm() == 16) ||
+ SecondOpcode == AArch64::INSTRUCTION_LIST_END;
+ // Upper half of 64 bit immediate.
case AArch64::MOVKXi:
- return FirstOpcode == AArch64::INSTRUCTION_LIST_END ||
- (FirstOpcode == AArch64::MOVZXi &&
- SecondMI.getOperand(3).getImm() == 16) ||
- (FirstMI->getOperand(3).getImm() == 32 &&
- FirstOpcode == AArch64::MOVKXi &&
- SecondMI.getOperand(3).getImm() == 48);
+ return FirstMI->getOperand(3).getImm() == 32 &&
+ ((SecondOpcode == AArch64::MOVKXi &&
+ SecondMI->getOperand(3).getImm() == 48) ||
+ SecondOpcode == AArch64::INSTRUCTION_LIST_END);
}
return false;
}
+/// \brief Implement the fusion of instr pairs in the scheduling DAG,
+/// anchored at the instr in AnchorSU..
+static bool scheduleAdjacentImpl(ScheduleDAGMI *DAG, SUnit &AnchorSU) {
+ const MachineInstr *AnchorMI = AnchorSU.getInstr();
+ if (!AnchorMI || AnchorMI->isPseudo() || AnchorMI->isTransient())
+ return false;
+
+ // If the anchor instr is the ExitSU, then consider its predecessors;
+ // otherwise, its successors.
+ bool Preds = (&AnchorSU == &DAG->ExitSU);
+ SmallVectorImpl<SDep> &AnchorDeps = Preds ? AnchorSU.Preds : AnchorSU.Succs;
+
+ const MachineInstr *FirstMI = Preds ? nullptr : AnchorMI;
+ const MachineInstr *SecondMI = Preds ? AnchorMI : nullptr;
+
+ // Check if the anchor instr may be fused.
+ if (!shouldScheduleAdjacent(*DAG->TII, DAG->MF.getSubtarget(),
+ FirstMI, SecondMI))
+ return false;
+
+ // Explorer for fusion candidates among the dependencies of the anchor instr.
+ for (SDep &Dep : AnchorDeps) {
+ // Ignore dependencies that don't enforce ordering.
+ if (Dep.isWeak())
+ continue;
+
+ SUnit &DepSU = *Dep.getSUnit();
+ // Ignore the ExitSU if the dependents are successors.
+ if (!Preds && &DepSU == &DAG->ExitSU)
+ continue;
+
+ const MachineInstr *DepMI = DepSU.getInstr();
+ if (!DepMI || DepMI->isPseudo() || DepMI->isTransient())
+ continue;
+
+ FirstMI = Preds ? DepMI : AnchorMI;
+ SecondMI = Preds ? AnchorMI : DepMI;
+ if (!shouldScheduleAdjacent(*DAG->TII, DAG->MF.getSubtarget(),
+ FirstMI, SecondMI))
+ continue;
+
+ // Create a single weak edge between the adjacent instrs. The only effect is
+ // to cause bottom-up scheduling to heavily prioritize the clustered instrs.
+ SUnit &FirstSU = Preds ? DepSU : AnchorSU;
+ SUnit &SecondSU = Preds ? AnchorSU : DepSU;
+ DAG->addEdge(&SecondSU, SDep(&FirstSU, SDep::Cluster));
+
+ // Adjust the latency between the anchor instr and its
+ // predecessors/successors.
+ for (SDep &IDep : AnchorDeps)
+ if (IDep.getSUnit() == &DepSU)
+ IDep.setLatency(0);
+
+ // Adjust the latency between the dependent instr and its
+ // successors/predecessors.
+ for (SDep &IDep : Preds ? DepSU.Succs : DepSU.Preds)
+ if (IDep.getSUnit() == &AnchorSU)
+ IDep.setLatency(0);
+
+ DEBUG(dbgs() << DAG->MF.getName() << "(): Macro fuse ";
+ FirstSU.print(dbgs(), DAG); dbgs() << " - ";
+ SecondSU.print(dbgs(), DAG); dbgs() << " / ";
+ dbgs() << DAG->TII->getName(FirstMI->getOpcode()) << " - " <<
+ DAG->TII->getName(SecondMI->getOpcode()) << '\n'; );
+
+ if (&SecondSU != &DAG->ExitSU)
+ // Make instructions dependent on FirstSU also dependent on SecondSU to
+ // prevent them from being scheduled between FirstSU and and SecondSU.
+ for (SUnit::const_succ_iterator
+ SI = FirstSU.Succs.begin(), SE = FirstSU.Succs.end();
+ SI != SE; ++SI) {
+ if (!SI->getSUnit() || SI->getSUnit() == &SecondSU)
+ continue;
+ DEBUG(dbgs() << " Copy Succ ";
+ SI->getSUnit()->print(dbgs(), DAG); dbgs() << '\n';);
+ DAG->addEdge(SI->getSUnit(), SDep(&SecondSU, SDep::Artificial));
+ }
+
+ ++NumFused;
+ return true;
+ }
+
+ return false;
+}
+
+/// \brief Post-process the DAG to create cluster edges between instrs that may
+/// be fused by the processor into a single operation.
+class AArch64MacroFusion : public ScheduleDAGMutation {
+public:
+ AArch64MacroFusion() {}
+
+ void apply(ScheduleDAGInstrs *DAGInstrs) override;
+};
+
+void AArch64MacroFusion::apply(ScheduleDAGInstrs *DAGInstrs) {
+ ScheduleDAGMI *DAG = static_cast<ScheduleDAGMI*>(DAGInstrs);
+
+ // For each of the SUnits in the scheduling block, try to fuse the instr in it
+ // with one in its successors.
+ for (SUnit &ISU : DAG->SUnits)
+ scheduleAdjacentImpl(DAG, ISU);
+
+ // Try to fuse the instr in the ExitSU with one in its predecessors.
+ scheduleAdjacentImpl(DAG, DAG->ExitSU);
+}
+
} // end namespace
namespace llvm {
std::unique_ptr<ScheduleDAGMutation> createAArch64MacroFusionDAGMutation () {
- return createMacroFusionDAGMutation(shouldScheduleAdjacent);
+ return EnableMacroFusion ? make_unique<AArch64MacroFusion>() : nullptr;
}
} // end namespace llvm
Modified: llvm/trunk/lib/Target/AArch64/AArch64MacroFusion.h
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Target/AArch64/AArch64MacroFusion.h?rev=305681&r1=305680&r2=305681&view=diff
==============================================================================
--- llvm/trunk/lib/Target/AArch64/AArch64MacroFusion.h (original)
+++ llvm/trunk/lib/Target/AArch64/AArch64MacroFusion.h Mon Jun 19 06:26:15 2017
@@ -2,18 +2,23 @@
//
// The LLVM Compiler Infrastructure
//
-// This file is distributed under the University of Illinois Open Source
+// \fileThis file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
-/// \file This file contains the AArch64 definition of the DAG scheduling
-/// mutation to pair instructions back to back.
+// This file contains the AArch64 definition of the DAG scheduling mutation
+// to pair instructions back to back.
//
//===----------------------------------------------------------------------===//
+#include "AArch64InstrInfo.h"
#include "llvm/CodeGen/MachineScheduler.h"
+//===----------------------------------------------------------------------===//
+// AArch64MacroFusion - DAG post-processing to encourage fusion of macro ops.
+//===----------------------------------------------------------------------===//
+
namespace llvm {
/// Note that you have to add:
Modified: llvm/trunk/lib/Target/X86/X86MacroFusion.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Target/X86/X86MacroFusion.cpp?rev=305681&r1=305680&r2=305681&view=diff
==============================================================================
--- llvm/trunk/lib/Target/X86/X86MacroFusion.cpp (original)
+++ llvm/trunk/lib/Target/X86/X86MacroFusion.cpp Mon Jun 19 06:26:15 2017
@@ -2,31 +2,39 @@
//
// The LLVM Compiler Infrastructure
//
-// This file is distributed under the University of Illinois Open Source
+// \file This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
-/// \file This file contains the X86 implementation of the DAG scheduling
-/// mutation to pair instructions back to back.
+// This file contains the X86 implementation of the DAG scheduling mutation to
+// pair instructions back to back.
//
//===----------------------------------------------------------------------===//
#include "X86MacroFusion.h"
#include "X86Subtarget.h"
+#include "llvm/ADT/Statistic.h"
+#include "llvm/Support/CommandLine.h"
#include "llvm/Target/TargetInstrInfo.h"
-#include "llvm/CodeGen/MacroFusion.h"
+
+#define DEBUG_TYPE "misched"
+
+STATISTIC(NumFused, "Number of instr pairs fused");
using namespace llvm;
-/// \brief Check if the instr pair, FirstMI and SecondMI, should be fused
-/// together. Given SecondMI, when FirstMI is unspecified, then check if
-/// SecondMI may be part of a fused pair at all.
-static bool shouldScheduleAdjacent(const TargetInstrInfo &TII,
- const TargetSubtargetInfo &TSI,
- const MachineInstr *FirstMI,
- const MachineInstr &SecondMI) {
- const X86Subtarget &ST = static_cast<const X86Subtarget&>(TSI);
+static cl::opt<bool> EnableMacroFusion("x86-misched-fusion", cl::Hidden,
+ cl::desc("Enable scheduling for macro fusion."), cl::init(true));
+
+namespace {
+
+/// \brief Verify that the instruction pair, First and Second,
+/// should be scheduled back to back. If either instruction is unspecified,
+/// then verify that the other instruction may be part of a pair at all.
+static bool shouldScheduleAdjacent(const X86Subtarget &ST,
+ const MachineInstr *First,
+ const MachineInstr *Second) {
// Check if this processor supports macro-fusion. Since this is a minor
// heuristic, we haven't specifically reserved a feature. hasAVX is a decent
// proxy for SandyBridge+.
@@ -39,10 +47,13 @@ static bool shouldScheduleAdjacent(const
FuseInc
} FuseKind;
- unsigned FirstOpcode = FirstMI
- ? FirstMI->getOpcode()
+ assert((First || Second) && "At least one instr must be specified");
+ unsigned FirstOpcode = First
+ ? First->getOpcode()
: static_cast<unsigned>(X86::INSTRUCTION_LIST_END);
- unsigned SecondOpcode = SecondMI.getOpcode();
+ unsigned SecondOpcode = Second
+ ? Second->getOpcode()
+ : static_cast<unsigned>(X86::INSTRUCTION_LIST_END);
switch (SecondOpcode) {
default:
@@ -192,11 +203,69 @@ static bool shouldScheduleAdjacent(const
}
}
+/// \brief Post-process the DAG to create cluster edges between instructions
+/// that may be fused by the processor into a single operation.
+class X86MacroFusion : public ScheduleDAGMutation {
+public:
+ X86MacroFusion() {}
+
+ void apply(ScheduleDAGInstrs *DAGInstrs) override;
+};
+
+void X86MacroFusion::apply(ScheduleDAGInstrs *DAGInstrs) {
+ ScheduleDAGMI *DAG = static_cast<ScheduleDAGMI*>(DAGInstrs);
+ const X86Subtarget &ST = DAG->MF.getSubtarget<X86Subtarget>();
+
+ // For now, assume targets can only fuse with the branch.
+ SUnit &ExitSU = DAG->ExitSU;
+ MachineInstr *Branch = ExitSU.getInstr();
+ if (!Branch || !shouldScheduleAdjacent(ST, nullptr, Branch))
+ return;
+
+ for (SDep &PredDep : ExitSU.Preds) {
+ if (PredDep.isWeak())
+ continue;
+ SUnit &SU = *PredDep.getSUnit();
+ MachineInstr &Pred = *SU.getInstr();
+ if (!shouldScheduleAdjacent(ST, &Pred, Branch))
+ continue;
+
+ // Create a single weak edge from SU to ExitSU. The only effect is to cause
+ // bottom-up scheduling to heavily prioritize the clustered SU. There is no
+ // need to copy predecessor edges from ExitSU to SU, since top-down
+ // scheduling cannot prioritize ExitSU anyway. To defer top-down scheduling
+ // of SU, we could create an artificial edge from the deepest root, but it
+ // hasn't been needed yet.
+ bool Success = DAG->addEdge(&ExitSU, SDep(&SU, SDep::Cluster));
+ (void)Success;
+ assert(Success && "No DAG nodes should be reachable from ExitSU");
+
+ // Adjust latency of data deps between the nodes.
+ for (SDep &PredDep : ExitSU.Preds)
+ if (PredDep.getSUnit() == &SU)
+ PredDep.setLatency(0);
+ for (SDep &SuccDep : SU.Succs)
+ if (SuccDep.getSUnit() == &ExitSU)
+ SuccDep.setLatency(0);
+
+ ++NumFused;
+ DEBUG(dbgs() << DAG->MF.getName() << "(): Macro fuse ";
+ SU.print(dbgs(), DAG);
+ dbgs() << " - ExitSU"
+ << " / " << DAG->TII->getName(Pred.getOpcode()) << " - "
+ << DAG->TII->getName(Branch->getOpcode()) << '\n';);
+
+ break;
+ }
+}
+
+} // end namespace
+
namespace llvm {
std::unique_ptr<ScheduleDAGMutation>
createX86MacroFusionDAGMutation () {
- return createBranchMacroFusionDAGMutation(shouldScheduleAdjacent);
+ return EnableMacroFusion ? make_unique<X86MacroFusion>() : nullptr;
}
} // end namespace llvm
Modified: llvm/trunk/lib/Target/X86/X86MacroFusion.h
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Target/X86/X86MacroFusion.h?rev=305681&r1=305680&r2=305681&view=diff
==============================================================================
--- llvm/trunk/lib/Target/X86/X86MacroFusion.h (original)
+++ llvm/trunk/lib/Target/X86/X86MacroFusion.h Mon Jun 19 06:26:15 2017
@@ -2,18 +2,23 @@
//
// The LLVM Compiler Infrastructure
//
-// This file is distributed under the University of Illinois Open Source
+// \file This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
-/// \file This file contains the X86 definition of the DAG scheduling mutation
-/// to pair instructions back to back.
+// This file contains the X86 definition of the DAG scheduling mutation to pair
+// instructions back to back.
//
//===----------------------------------------------------------------------===//
+#include "X86InstrInfo.h"
#include "llvm/CodeGen/MachineScheduler.h"
+//===----------------------------------------------------------------------===//
+// X86MacroFusion - DAG post-processing to encourage fusion of macro ops.
+//===----------------------------------------------------------------------===//
+
namespace llvm {
/// Note that you have to add:
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