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Diffstat (limited to 'include/llvm/CodeGen/ExecutionDepsFix.h')
| -rw-r--r-- | include/llvm/CodeGen/ExecutionDepsFix.h | 230 |
1 files changed, 0 insertions, 230 deletions
diff --git a/include/llvm/CodeGen/ExecutionDepsFix.h b/include/llvm/CodeGen/ExecutionDepsFix.h deleted file mode 100644 index f4db8b7322da..000000000000 --- a/include/llvm/CodeGen/ExecutionDepsFix.h +++ /dev/null @@ -1,230 +0,0 @@ -//==- llvm/CodeGen/ExecutionDepsFix.h - Execution Dependency Fix -*- C++ -*-==// -// -// The LLVM Compiler Infrastructure -// -// This file is distributed under the University of Illinois Open Source -// License. See LICENSE.TXT for details. -// -//===----------------------------------------------------------------------===// -// -/// \file Execution Dependency Fix pass. -/// -/// Some X86 SSE instructions like mov, and, or, xor are available in different -/// variants for different operand types. These variant instructions are -/// equivalent, but on Nehalem and newer cpus there is extra latency -/// transferring data between integer and floating point domains. ARM cores -/// have similar issues when they are configured with both VFP and NEON -/// pipelines. -/// -/// This pass changes the variant instructions to minimize domain crossings. -// -//===----------------------------------------------------------------------===// - -#ifndef LLVM_CODEGEN_EXECUTIONDEPSFIX_H -#define LLVM_CODEGEN_EXECUTIONDEPSFIX_H - -#include "llvm/ADT/DenseMap.h" -#include "llvm/ADT/iterator_range.h" -#include "llvm/ADT/SmallVector.h" -#include "llvm/CodeGen/LivePhysRegs.h" -#include "llvm/CodeGen/MachineFunction.h" -#include "llvm/CodeGen/MachineFunctionPass.h" -#include "llvm/CodeGen/RegisterClassInfo.h" -#include "llvm/Pass.h" -#include "llvm/Support/Allocator.h" -#include "llvm/Support/MathExtras.h" -#include <cassert> -#include <limits> -#include <utility> -#include <vector> - -namespace llvm { - -class MachineBasicBlock; -class MachineInstr; -class TargetInstrInfo; - -/// A DomainValue is a bit like LiveIntervals' ValNo, but it also keeps track -/// of execution domains. -/// -/// An open DomainValue represents a set of instructions that can still switch -/// execution domain. Multiple registers may refer to the same open -/// DomainValue - they will eventually be collapsed to the same execution -/// domain. -/// -/// A collapsed DomainValue represents a single register that has been forced -/// into one of more execution domains. There is a separate collapsed -/// DomainValue for each register, but it may contain multiple execution -/// domains. A register value is initially created in a single execution -/// domain, but if we were forced to pay the penalty of a domain crossing, we -/// keep track of the fact that the register is now available in multiple -/// domains. -struct DomainValue { - // Basic reference counting. - unsigned Refs = 0; - - // Bitmask of available domains. For an open DomainValue, it is the still - // possible domains for collapsing. For a collapsed DomainValue it is the - // domains where the register is available for free. - unsigned AvailableDomains; - - // Pointer to the next DomainValue in a chain. When two DomainValues are - // merged, Victim.Next is set to point to Victor, so old DomainValue - // references can be updated by following the chain. - DomainValue *Next; - - // Twiddleable instructions using or defining these registers. - SmallVector<MachineInstr*, 8> Instrs; - - DomainValue() { clear(); } - - // A collapsed DomainValue has no instructions to twiddle - it simply keeps - // track of the domains where the registers are already available. - bool isCollapsed() const { return Instrs.empty(); } - - // Is domain available? - bool hasDomain(unsigned domain) const { - assert(domain < - static_cast<unsigned>(std::numeric_limits<unsigned>::digits) && - "undefined behavior"); - return AvailableDomains & (1u << domain); - } - - // Mark domain as available. - void addDomain(unsigned domain) { - AvailableDomains |= 1u << domain; - } - - // Restrict to a single domain available. - void setSingleDomain(unsigned domain) { - AvailableDomains = 1u << domain; - } - - // Return bitmask of domains that are available and in mask. - unsigned getCommonDomains(unsigned mask) const { - return AvailableDomains & mask; - } - - // First domain available. - unsigned getFirstDomain() const { - return countTrailingZeros(AvailableDomains); - } - - // Clear this DomainValue and point to next which has all its data. - void clear() { - AvailableDomains = 0; - Next = nullptr; - Instrs.clear(); - } -}; - -/// Information about a live register. -struct LiveReg { - /// Value currently in this register, or NULL when no value is being tracked. - /// This counts as a DomainValue reference. - DomainValue *Value; - - /// Instruction that defined this register, relative to the beginning of the - /// current basic block. When a LiveReg is used to represent a live-out - /// register, this value is relative to the end of the basic block, so it - /// will be a negative number. - int Def; -}; - -class ExecutionDepsFix : public MachineFunctionPass { - SpecificBumpPtrAllocator<DomainValue> Allocator; - SmallVector<DomainValue*,16> Avail; - - const TargetRegisterClass *const RC; - MachineFunction *MF; - const TargetInstrInfo *TII; - const TargetRegisterInfo *TRI; - RegisterClassInfo RegClassInfo; - std::vector<SmallVector<int, 1>> AliasMap; - const unsigned NumRegs; - LiveReg *LiveRegs; - struct MBBInfo { - // Keeps clearance and domain information for all registers. Note that this - // is different from the usual definition notion of liveness. The CPU - // doesn't care whether or not we consider a register killed. - LiveReg *OutRegs = nullptr; - - // Whether we have gotten to this block in primary processing yet. - bool PrimaryCompleted = false; - - // The number of predecessors for which primary processing has completed - unsigned IncomingProcessed = 0; - - // The value of `IncomingProcessed` at the start of primary processing - unsigned PrimaryIncoming = 0; - - // The number of predecessors for which all processing steps are done. - unsigned IncomingCompleted = 0; - - MBBInfo() = default; - }; - using MBBInfoMap = DenseMap<MachineBasicBlock *, MBBInfo>; - MBBInfoMap MBBInfos; - - /// List of undefined register reads in this block in forward order. - std::vector<std::pair<MachineInstr *, unsigned>> UndefReads; - - /// Storage for register unit liveness. - LivePhysRegs LiveRegSet; - - /// Current instruction number. - /// The first instruction in each basic block is 0. - int CurInstr; - -public: - ExecutionDepsFix(char &PassID, const TargetRegisterClass &RC) - : MachineFunctionPass(PassID), RC(&RC), NumRegs(RC.getNumRegs()) {} - - void getAnalysisUsage(AnalysisUsage &AU) const override { - AU.setPreservesAll(); - MachineFunctionPass::getAnalysisUsage(AU); - } - - bool runOnMachineFunction(MachineFunction &MF) override; - - MachineFunctionProperties getRequiredProperties() const override { - return MachineFunctionProperties().set( - MachineFunctionProperties::Property::NoVRegs); - } - -private: - iterator_range<SmallVectorImpl<int>::const_iterator> - regIndices(unsigned Reg) const; - // DomainValue allocation. - DomainValue *alloc(int domain = -1); - DomainValue *retain(DomainValue *DV) { - if (DV) ++DV->Refs; - return DV; - } - void release(DomainValue*); - DomainValue *resolve(DomainValue*&); - - // LiveRegs manipulations. - void setLiveReg(int rx, DomainValue *DV); - void kill(int rx); - void force(int rx, unsigned domain); - void collapse(DomainValue *dv, unsigned domain); - bool merge(DomainValue *A, DomainValue *B); - - void enterBasicBlock(MachineBasicBlock*); - void leaveBasicBlock(MachineBasicBlock*); - bool isBlockDone(MachineBasicBlock *); - void processBasicBlock(MachineBasicBlock *MBB, bool PrimaryPass); - bool visitInstr(MachineInstr *); - void processDefs(MachineInstr *, bool breakDependency, bool Kill); - void visitSoftInstr(MachineInstr*, unsigned mask); - void visitHardInstr(MachineInstr*, unsigned domain); - bool pickBestRegisterForUndef(MachineInstr *MI, unsigned OpIdx, - unsigned Pref); - bool shouldBreakDependence(MachineInstr*, unsigned OpIdx, unsigned Pref); - void processUndefReads(MachineBasicBlock*); -}; - -} // end namepsace llvm - -#endif // LLVM_CODEGEN_EXECUTIONDEPSFIX_H |