llvm-6502/lib/Target/X86/X86Subtarget.h
Ekaterina Romanova 46f7257ed1 SHLD/SHRD are VectorPath (microcode) instructions known to have poor latency on certain architectures. While generating SHLD/SHRD instructions is acceptable when optimizing for size, optimizing for speed on these platforms should be implemented using alternative sequences of instructions composed of add, adc, shr, shl, or and lea which are directPath instructions. These alternative instructions not only have a lower latency but they also increase the decode bandwidth by allowing simultaneous decoding of a third directPath instruction.
AMD's processors family K7, K8, K10, K12, K15 and K16 are known to have SHLD/SHRD instructions with very poor latency. Optimization guides for these processors recommend using an alternative sequence of instructions. For these AMD's processors, I disabled folding (or (x << c) | (y >> (64 - c))) when we are not optimizing for size.

It might be beneficial to disable this folding for some of the Intel's processors. However, since I couldn't find specific recommendations regarding using SHLD/SHRD instructions on Intel's processors, I haven't disabled this peephole for Intel.



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@195383 91177308-0d34-0410-b5e6-96231b3b80d8
2013-11-21 23:21:26 +00:00

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//===-- X86Subtarget.h - Define Subtarget for the X86 ----------*- C++ -*--===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// This file declares the X86 specific subclass of TargetSubtargetInfo.
//
//===----------------------------------------------------------------------===//
#ifndef X86SUBTARGET_H
#define X86SUBTARGET_H
#include "llvm/ADT/Triple.h"
#include "llvm/IR/CallingConv.h"
#include "llvm/Target/TargetSubtargetInfo.h"
#include <string>
#define GET_SUBTARGETINFO_HEADER
#include "X86GenSubtargetInfo.inc"
namespace llvm {
class GlobalValue;
class StringRef;
class TargetMachine;
/// PICStyles - The X86 backend supports a number of different styles of PIC.
///
namespace PICStyles {
enum Style {
StubPIC, // Used on i386-darwin in -fPIC mode.
StubDynamicNoPIC, // Used on i386-darwin in -mdynamic-no-pic mode.
GOT, // Used on many 32-bit unices in -fPIC mode.
RIPRel, // Used on X86-64 when not in -static mode.
None // Set when in -static mode (not PIC or DynamicNoPIC mode).
};
}
class X86Subtarget : public X86GenSubtargetInfo {
protected:
enum X86SSEEnum {
NoMMXSSE, MMX, SSE1, SSE2, SSE3, SSSE3, SSE41, SSE42, AVX, AVX2, AVX512F
};
enum X863DNowEnum {
NoThreeDNow, ThreeDNow, ThreeDNowA
};
enum X86ProcFamilyEnum {
Others, IntelAtom, IntelSLM
};
/// X86ProcFamily - X86 processor family: Intel Atom, and others
X86ProcFamilyEnum X86ProcFamily;
/// PICStyle - Which PIC style to use
///
PICStyles::Style PICStyle;
/// X86SSELevel - MMX, SSE1, SSE2, SSE3, SSSE3, SSE41, SSE42, or
/// none supported.
X86SSEEnum X86SSELevel;
/// X863DNowLevel - 3DNow or 3DNow Athlon, or none supported.
///
X863DNowEnum X863DNowLevel;
/// HasCMov - True if this processor has conditional move instructions
/// (generally pentium pro+).
bool HasCMov;
/// HasX86_64 - True if the processor supports X86-64 instructions.
///
bool HasX86_64;
/// HasPOPCNT - True if the processor supports POPCNT.
bool HasPOPCNT;
/// HasSSE4A - True if the processor supports SSE4A instructions.
bool HasSSE4A;
/// HasAES - Target has AES instructions
bool HasAES;
/// HasPCLMUL - Target has carry-less multiplication
bool HasPCLMUL;
/// HasFMA - Target has 3-operand fused multiply-add
bool HasFMA;
/// HasFMA4 - Target has 4-operand fused multiply-add
bool HasFMA4;
/// HasXOP - Target has XOP instructions
bool HasXOP;
/// HasTBM - Target has TBM instructions.
bool HasTBM;
/// HasMOVBE - True if the processor has the MOVBE instruction.
bool HasMOVBE;
/// HasRDRAND - True if the processor has the RDRAND instruction.
bool HasRDRAND;
/// HasF16C - Processor has 16-bit floating point conversion instructions.
bool HasF16C;
/// HasFSGSBase - Processor has FS/GS base insturctions.
bool HasFSGSBase;
/// HasLZCNT - Processor has LZCNT instruction.
bool HasLZCNT;
/// HasBMI - Processor has BMI1 instructions.
bool HasBMI;
/// HasBMI2 - Processor has BMI2 instructions.
bool HasBMI2;
/// HasRTM - Processor has RTM instructions.
bool HasRTM;
/// HasHLE - Processor has HLE.
bool HasHLE;
/// HasADX - Processor has ADX instructions.
bool HasADX;
/// HasSHA - Processor has SHA instructions.
bool HasSHA;
/// HasPRFCHW - Processor has PRFCHW instructions.
bool HasPRFCHW;
/// HasRDSEED - Processor has RDSEED instructions.
bool HasRDSEED;
/// IsBTMemSlow - True if BT (bit test) of memory instructions are slow.
bool IsBTMemSlow;
/// IsSHLDSlow - True if SHLD instructions are slow.
bool IsSHLDSlow;
/// IsUAMemFast - True if unaligned memory access is fast.
bool IsUAMemFast;
/// HasVectorUAMem - True if SIMD operations can have unaligned memory
/// operands. This may require setting a feature bit in the processor.
bool HasVectorUAMem;
/// HasCmpxchg16b - True if this processor has the CMPXCHG16B instruction;
/// this is true for most x86-64 chips, but not the first AMD chips.
bool HasCmpxchg16b;
/// UseLeaForSP - True if the LEA instruction should be used for adjusting
/// the stack pointer. This is an optimization for Intel Atom processors.
bool UseLeaForSP;
/// HasSlowDivide - True if smaller divides are significantly faster than
/// full divides and should be used when possible.
bool HasSlowDivide;
/// PostRAScheduler - True if using post-register-allocation scheduler.
bool PostRAScheduler;
/// PadShortFunctions - True if the short functions should be padded to prevent
/// a stall when returning too early.
bool PadShortFunctions;
/// CallRegIndirect - True if the Calls with memory reference should be converted
/// to a register-based indirect call.
bool CallRegIndirect;
/// LEAUsesAG - True if the LEA instruction inputs have to be ready at
/// address generation (AG) time.
bool LEAUsesAG;
/// Processor has AVX-512 PreFetch Instructions
bool HasPFI;
/// Processor has AVX-512 Exponential and Reciprocal Instructions
bool HasERI;
/// Processor has AVX-512 Conflict Detection Instructions
bool HasCDI;
/// stackAlignment - The minimum alignment known to hold of the stack frame on
/// entry to the function and which must be maintained by every function.
unsigned stackAlignment;
/// Max. memset / memcpy size that is turned into rep/movs, rep/stos ops.
///
unsigned MaxInlineSizeThreshold;
/// TargetTriple - What processor and OS we're targeting.
Triple TargetTriple;
/// Instruction itineraries for scheduling
InstrItineraryData InstrItins;
private:
/// StackAlignOverride - Override the stack alignment.
unsigned StackAlignOverride;
/// In64BitMode - True if compiling for 64-bit, false for 32-bit.
bool In64BitMode;
public:
/// This constructor initializes the data members to match that
/// of the specified triple.
///
X86Subtarget(const std::string &TT, const std::string &CPU,
const std::string &FS,
unsigned StackAlignOverride, bool is64Bit);
/// getStackAlignment - Returns the minimum alignment known to hold of the
/// stack frame on entry to the function and which must be maintained by every
/// function for this subtarget.
unsigned getStackAlignment() const { return stackAlignment; }
/// getMaxInlineSizeThreshold - Returns the maximum memset / memcpy size
/// that still makes it profitable to inline the call.
unsigned getMaxInlineSizeThreshold() const { return MaxInlineSizeThreshold; }
/// ParseSubtargetFeatures - Parses features string setting specified
/// subtarget options. Definition of function is auto generated by tblgen.
void ParseSubtargetFeatures(StringRef CPU, StringRef FS);
/// AutoDetectSubtargetFeatures - Auto-detect CPU features using CPUID
/// instruction.
void AutoDetectSubtargetFeatures();
/// \brief Reset the features for the X86 target.
virtual void resetSubtargetFeatures(const MachineFunction *MF);
private:
void initializeEnvironment();
void resetSubtargetFeatures(StringRef CPU, StringRef FS);
public:
/// Is this x86_64? (disregarding specific ABI / programming model)
bool is64Bit() const {
return In64BitMode;
}
/// Is this x86_64 with the ILP32 programming model (x32 ABI)?
bool isTarget64BitILP32() const {
return In64BitMode && (TargetTriple.getEnvironment() == Triple::GNUX32);
}
/// Is this x86_64 with the LP64 programming model (standard AMD64, no x32)?
bool isTarget64BitLP64() const {
return In64BitMode && (TargetTriple.getEnvironment() != Triple::GNUX32);
}
PICStyles::Style getPICStyle() const { return PICStyle; }
void setPICStyle(PICStyles::Style Style) { PICStyle = Style; }
bool hasCMov() const { return HasCMov; }
bool hasMMX() const { return X86SSELevel >= MMX; }
bool hasSSE1() const { return X86SSELevel >= SSE1; }
bool hasSSE2() const { return X86SSELevel >= SSE2; }
bool hasSSE3() const { return X86SSELevel >= SSE3; }
bool hasSSSE3() const { return X86SSELevel >= SSSE3; }
bool hasSSE41() const { return X86SSELevel >= SSE41; }
bool hasSSE42() const { return X86SSELevel >= SSE42; }
bool hasAVX() const { return X86SSELevel >= AVX; }
bool hasAVX2() const { return X86SSELevel >= AVX2; }
bool hasAVX512() const { return X86SSELevel >= AVX512F; }
bool hasFp256() const { return hasAVX(); }
bool hasInt256() const { return hasAVX2(); }
bool hasSSE4A() const { return HasSSE4A; }
bool has3DNow() const { return X863DNowLevel >= ThreeDNow; }
bool has3DNowA() const { return X863DNowLevel >= ThreeDNowA; }
bool hasPOPCNT() const { return HasPOPCNT; }
bool hasAES() const { return HasAES; }
bool hasPCLMUL() const { return HasPCLMUL; }
bool hasFMA() const { return HasFMA; }
// FIXME: Favor FMA when both are enabled. Is this the right thing to do?
bool hasFMA4() const { return HasFMA4 && !HasFMA; }
bool hasXOP() const { return HasXOP; }
bool hasTBM() const { return HasTBM; }
bool hasMOVBE() const { return HasMOVBE; }
bool hasRDRAND() const { return HasRDRAND; }
bool hasF16C() const { return HasF16C; }
bool hasFSGSBase() const { return HasFSGSBase; }
bool hasLZCNT() const { return HasLZCNT; }
bool hasBMI() const { return HasBMI; }
bool hasBMI2() const { return HasBMI2; }
bool hasRTM() const { return HasRTM; }
bool hasHLE() const { return HasHLE; }
bool hasADX() const { return HasADX; }
bool hasSHA() const { return HasSHA; }
bool hasPRFCHW() const { return HasPRFCHW; }
bool hasRDSEED() const { return HasRDSEED; }
bool isBTMemSlow() const { return IsBTMemSlow; }
bool isSHLDSlow() const { return IsSHLDSlow; }
bool isUnalignedMemAccessFast() const { return IsUAMemFast; }
bool hasVectorUAMem() const { return HasVectorUAMem; }
bool hasCmpxchg16b() const { return HasCmpxchg16b; }
bool useLeaForSP() const { return UseLeaForSP; }
bool hasSlowDivide() const { return HasSlowDivide; }
bool padShortFunctions() const { return PadShortFunctions; }
bool callRegIndirect() const { return CallRegIndirect; }
bool LEAusesAG() const { return LEAUsesAG; }
bool hasCDI() const { return HasCDI; }
bool hasPFI() const { return HasPFI; }
bool hasERI() const { return HasERI; }
bool isAtom() const { return X86ProcFamily == IntelAtom; }
const Triple &getTargetTriple() const { return TargetTriple; }
bool isTargetDarwin() const { return TargetTriple.isOSDarwin(); }
bool isTargetFreeBSD() const {
return TargetTriple.getOS() == Triple::FreeBSD;
}
bool isTargetSolaris() const {
return TargetTriple.getOS() == Triple::Solaris;
}
bool isTargetELF() const {
return (TargetTriple.getEnvironment() == Triple::ELF ||
TargetTriple.isOSBinFormatELF());
}
bool isTargetLinux() const { return TargetTriple.isOSLinux(); }
bool isTargetNaCl() const { return TargetTriple.isOSNaCl(); }
bool isTargetNaCl32() const { return isTargetNaCl() && !is64Bit(); }
bool isTargetNaCl64() const { return isTargetNaCl() && is64Bit(); }
bool isTargetWindows() const { return TargetTriple.getOS() == Triple::Win32; }
bool isTargetMingw() const { return TargetTriple.getOS() == Triple::MinGW32; }
bool isTargetCygwin() const { return TargetTriple.getOS() == Triple::Cygwin; }
bool isTargetCygMing() const { return TargetTriple.isOSCygMing(); }
bool isTargetCOFF() const {
return (TargetTriple.getEnvironment() != Triple::ELF &&
TargetTriple.isOSBinFormatCOFF());
}
bool isTargetEnvMacho() const { return TargetTriple.isEnvironmentMachO(); }
bool isOSWindows() const { return TargetTriple.isOSWindows(); }
bool isTargetWin64() const {
return In64BitMode && TargetTriple.isOSWindows();
}
bool isTargetWin32() const {
return !In64BitMode && (isTargetCygMing() || isTargetWindows());
}
bool isPICStyleSet() const { return PICStyle != PICStyles::None; }
bool isPICStyleGOT() const { return PICStyle == PICStyles::GOT; }
bool isPICStyleRIPRel() const { return PICStyle == PICStyles::RIPRel; }
bool isPICStyleStubPIC() const {
return PICStyle == PICStyles::StubPIC;
}
bool isPICStyleStubNoDynamic() const {
return PICStyle == PICStyles::StubDynamicNoPIC;
}
bool isPICStyleStubAny() const {
return PICStyle == PICStyles::StubDynamicNoPIC ||
PICStyle == PICStyles::StubPIC;
}
bool isCallingConvWin64(CallingConv::ID CC) const {
return (isTargetWin64() && CC != CallingConv::X86_64_SysV) ||
CC == CallingConv::X86_64_Win64;
}
/// ClassifyGlobalReference - Classify a global variable reference for the
/// current subtarget according to how we should reference it in a non-pcrel
/// context.
unsigned char ClassifyGlobalReference(const GlobalValue *GV,
const TargetMachine &TM)const;
/// ClassifyBlockAddressReference - Classify a blockaddress reference for the
/// current subtarget according to how we should reference it in a non-pcrel
/// context.
unsigned char ClassifyBlockAddressReference() const;
/// IsLegalToCallImmediateAddr - Return true if the subtarget allows calls
/// to immediate address.
bool IsLegalToCallImmediateAddr(const TargetMachine &TM) const;
/// This function returns the name of a function which has an interface
/// like the non-standard bzero function, if such a function exists on
/// the current subtarget and it is considered prefereable over
/// memset with zero passed as the second argument. Otherwise it
/// returns null.
const char *getBZeroEntry() const;
/// This function returns true if the target has sincos() routine in its
/// compiler runtime or math libraries.
bool hasSinCos() const;
/// Enable the MachineScheduler pass for all X86 subtargets.
bool enableMachineScheduler() const LLVM_OVERRIDE { return true; }
/// enablePostRAScheduler - run for Atom optimization.
bool enablePostRAScheduler(CodeGenOpt::Level OptLevel,
TargetSubtargetInfo::AntiDepBreakMode& Mode,
RegClassVector& CriticalPathRCs) const;
bool postRAScheduler() const { return PostRAScheduler; }
/// getInstrItins = Return the instruction itineraries based on the
/// subtarget selection.
const InstrItineraryData &getInstrItineraryData() const { return InstrItins; }
};
} // End llvm namespace
#endif