[llvm] r239001 - make reciprocal estimate code generation more flexible by adding command-line options (3rd try)
Matthias Braun
mbraun at apple.com
Fri Jun 5 14:34:37 PDT 2015
This breaks -DBUILD_SHARED_LIBS=ON for me in an llvm+clang build:
[10/92] Linking CXX shared library lib/libclangCodeGen.3.7.0svn.dylib
FAILED: : && /usr/bin/c++ -fPIC -fvisibility-inlines-hidden -Wall -W -Wno-unused-parameter -Wwrite-strings -Wcast-qual -Wmissing-field-initializers -pedantic -Wno-long-long -Wcovered-switch-default -std=c++11 -fcolor-diagnostics -fno-common -Woverloaded-virtual -fno-strict-aliasing -Wno-nested-anon-types -g -dynamiclib -Wl,-headerpad_max_install_names -o lib/libclangCodeGen.3.7.0svn.dylib ...
Undefined symbols for architecture x86_64:
"llvm::TargetRecip::TargetRecip()", referenced from:
llvm::TargetOptions::TargetOptions() in BackendUtil.cpp.o
ld: symbol(s) not found for architecture x86_64
clang: error: linker command failed with exit code 1 (use -v to see invocation)
- Matthias
> On Jun 3, 2015, at 6:32 PM, Sanjay Patel <spatel at rotateright.com> wrote:
>
> Author: spatel
> Date: Wed Jun 3 20:32:35 2015
> New Revision: 239001
>
> URL: http://llvm.org/viewvc/llvm-project?rev=239001&view=rev
> Log:
> make reciprocal estimate code generation more flexible by adding command-line options (3rd try)
>
> The first try (r238051) to land this was reverted due to ExecutionEngine build failure;
> that was hopefully addressed by r238788.
>
> The second try (r238842) to land this was reverted due to BUILD_SHARED_LIBS failure;
> that was hopefully addressed by r238953.
>
> This patch adds a TargetRecip class for processing many recip codegen possibilities.
> The class is intended to handle both command-line options to llc as well
> as options passed in from a front-end such as clang with the -mrecip option.
>
> The x86 backend is updated to use the new functionality.
> Only -mcpu=btver2 with -ffast-math should see a functional change from this patch.
> All other x86 CPUs continue to *not* use reciprocal estimates by default with -ffast-math.
>
> Differential Revision: http://reviews.llvm.org/D8982
>
>
> Added:
> llvm/trunk/include/llvm/Target/TargetRecip.h
> llvm/trunk/lib/Target/TargetRecip.cpp
> Modified:
> llvm/trunk/include/llvm/CodeGen/CommandFlags.h
> llvm/trunk/include/llvm/Target/TargetOptions.h
> llvm/trunk/lib/Target/CMakeLists.txt
> llvm/trunk/lib/Target/X86/X86.td
> llvm/trunk/lib/Target/X86/X86ISelLowering.cpp
> llvm/trunk/lib/Target/X86/X86Subtarget.cpp
> llvm/trunk/lib/Target/X86/X86Subtarget.h
> llvm/trunk/lib/Target/X86/X86TargetMachine.cpp
> llvm/trunk/test/CodeGen/X86/recip-fastmath.ll
> llvm/trunk/test/CodeGen/X86/sqrt-fastmath.ll
>
> Modified: llvm/trunk/include/llvm/CodeGen/CommandFlags.h
> URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/include/llvm/CodeGen/CommandFlags.h?rev=239001&r1=239000&r2=239001&view=diff
> ==============================================================================
> --- llvm/trunk/include/llvm/CodeGen/CommandFlags.h (original)
> +++ llvm/trunk/include/llvm/CodeGen/CommandFlags.h Wed Jun 3 20:32:35 2015
> @@ -24,6 +24,7 @@
> #include "llvm/Support/Host.h"
> #include "llvm/Target/TargetMachine.h"
> #include "llvm/Target/TargetOptions.h"
> +#include "llvm/Target/TargetRecip.h"
> #include <string>
> using namespace llvm;
>
> @@ -152,6 +153,12 @@ FuseFPOps("fp-contract",
> "Only fuse FP ops when the result won't be effected."),
> clEnumValEnd));
>
> +cl::list<std::string>
> +ReciprocalOps("recip",
> + cl::CommaSeparated,
> + cl::desc("Choose reciprocal operation types and parameters."),
> + cl::value_desc("all,none,default,divf,!vec-sqrtd,vec-divd:0,sqrt:9..."));
> +
> cl::opt<bool>
> DontPlaceZerosInBSS("nozero-initialized-in-bss",
> cl::desc("Don't place zero-initialized symbols into bss section"),
> @@ -230,6 +237,7 @@ static inline TargetOptions InitTargetOp
> TargetOptions Options;
> Options.LessPreciseFPMADOption = EnableFPMAD;
> Options.AllowFPOpFusion = FuseFPOps;
> + Options.Reciprocals = TargetRecip(ReciprocalOps);
> Options.UnsafeFPMath = EnableUnsafeFPMath;
> Options.NoInfsFPMath = EnableNoInfsFPMath;
> Options.NoNaNsFPMath = EnableNoNaNsFPMath;
>
> Modified: llvm/trunk/include/llvm/Target/TargetOptions.h
> URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/include/llvm/Target/TargetOptions.h?rev=239001&r1=239000&r2=239001&view=diff
> ==============================================================================
> --- llvm/trunk/include/llvm/Target/TargetOptions.h (original)
> +++ llvm/trunk/include/llvm/Target/TargetOptions.h Wed Jun 3 20:32:35 2015
> @@ -15,6 +15,7 @@
> #ifndef LLVM_TARGET_TARGETOPTIONS_H
> #define LLVM_TARGET_TARGETOPTIONS_H
>
> +#include "llvm/Target/TargetRecip.h"
> #include "llvm/MC/MCTargetOptions.h"
> #include <string>
>
> @@ -72,7 +73,8 @@ namespace llvm {
> CompressDebugSections(false), FunctionSections(false),
> DataSections(false), UniqueSectionNames(true), TrapUnreachable(false),
> TrapFuncName(), FloatABIType(FloatABI::Default),
> - AllowFPOpFusion(FPOpFusion::Standard), JTType(JumpTable::Single),
> + AllowFPOpFusion(FPOpFusion::Standard), Reciprocals(TargetRecip()),
> + JTType(JumpTable::Single),
> ThreadModel(ThreadModel::POSIX) {}
>
> /// PrintMachineCode - This flag is enabled when the -print-machineinstrs
> @@ -206,6 +208,9 @@ namespace llvm {
> /// the value of this option.
> FPOpFusion::FPOpFusionMode AllowFPOpFusion;
>
> + /// This class encapsulates options for reciprocal-estimate code generation.
> + TargetRecip Reciprocals;
> +
> /// JTType - This flag specifies the type of jump-instruction table to
> /// create for functions that have the jumptable attribute.
> JumpTable::JumpTableType JTType;
> @@ -240,6 +245,7 @@ inline bool operator==(const TargetOptio
> ARE_EQUAL(TrapFuncName) &&
> ARE_EQUAL(FloatABIType) &&
> ARE_EQUAL(AllowFPOpFusion) &&
> + ARE_EQUAL(Reciprocals) &&
> ARE_EQUAL(JTType) &&
> ARE_EQUAL(ThreadModel) &&
> ARE_EQUAL(MCOptions);
>
> Added: llvm/trunk/include/llvm/Target/TargetRecip.h
> URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/include/llvm/Target/TargetRecip.h?rev=239001&view=auto
> ==============================================================================
> --- llvm/trunk/include/llvm/Target/TargetRecip.h (added)
> +++ llvm/trunk/include/llvm/Target/TargetRecip.h Wed Jun 3 20:32:35 2015
> @@ -0,0 +1,73 @@
> +//===--------------------- llvm/Target/TargetRecip.h ------------*- C++ -*-===//
> +//
> +// The LLVM Compiler Infrastructure
> +//
> +// This file is distributed under the University of Illinois Open Source
> +// License. See LICENSE.TXT for details.
> +//
> +//===----------------------------------------------------------------------===//
> +//
> +// This class is used to customize machine-specific reciprocal estimate code
> +// generation in a target-independent way.
> +// If a target does not support operations in this specification, then code
> +// generation will default to using supported operations.
> +//
> +//===----------------------------------------------------------------------===//
> +
> +#ifndef LLVM_TARGET_TARGETRECIP_H
> +#define LLVM_TARGET_TARGETRECIP_H
> +
> +#include "llvm/ADT/StringRef.h"
> +#include <vector>
> +#include <string>
> +#include <map>
> +
> +namespace llvm {
> +
> +struct TargetRecip {
> +public:
> + TargetRecip();
> +
> + /// Initialize all or part of the operations from command-line options or
> + /// a front end.
> + TargetRecip(const std::vector<std::string> &Args);
> +
> + /// Set whether a particular reciprocal operation is enabled and how many
> + /// refinement steps are needed when using it. Use "all" to set enablement
> + /// and refinement steps for all operations.
> + void setDefaults(const StringRef &Key, bool Enable, unsigned RefSteps);
> +
> + /// Return true if the reciprocal operation has been enabled by default or
> + /// from the command-line. Return false if the operation has been disabled
> + /// by default or from the command-line.
> + bool isEnabled(const StringRef &Key) const;
> +
> + /// Return the number of iterations necessary to refine the
> + /// the result of a machine instruction for the given reciprocal operation.
> + unsigned getRefinementSteps(const StringRef &Key) const;
> +
> + bool operator==(const TargetRecip &Other) const;
> +
> +private:
> + enum {
> + Uninitialized = -1
> + };
> +
> + struct RecipParams {
> + int8_t Enabled;
> + int8_t RefinementSteps;
> +
> + RecipParams() : Enabled(Uninitialized), RefinementSteps(Uninitialized) {}
> + };
> +
> + std::map<StringRef, RecipParams> RecipMap;
> + typedef std::map<StringRef, RecipParams>::iterator RecipIter;
> + typedef std::map<StringRef, RecipParams>::const_iterator ConstRecipIter;
> +
> + bool parseGlobalParams(const std::string &Arg);
> + void parseIndividualParams(const std::vector<std::string> &Args);
> +};
> +
> +} // End llvm namespace
> +
> +#endif
>
> Modified: llvm/trunk/lib/Target/CMakeLists.txt
> URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Target/CMakeLists.txt?rev=239001&r1=239000&r2=239001&view=diff
> ==============================================================================
> --- llvm/trunk/lib/Target/CMakeLists.txt (original)
> +++ llvm/trunk/lib/Target/CMakeLists.txt Wed Jun 3 20:32:35 2015
> @@ -6,6 +6,7 @@ add_llvm_library(LLVMTarget
> TargetLoweringObjectFile.cpp
> TargetMachine.cpp
> TargetMachineC.cpp
> + TargetRecip.cpp
> TargetSubtargetInfo.cpp
>
> ADDITIONAL_HEADER_DIRS
>
> Added: llvm/trunk/lib/Target/TargetRecip.cpp
> URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Target/TargetRecip.cpp?rev=239001&view=auto
> ==============================================================================
> --- llvm/trunk/lib/Target/TargetRecip.cpp (added)
> +++ llvm/trunk/lib/Target/TargetRecip.cpp Wed Jun 3 20:32:35 2015
> @@ -0,0 +1,225 @@
> +//===-------------------------- TargetRecip.cpp ---------------------------===//
> +//
> +// The LLVM Compiler Infrastructure
> +//
> +// This file is distributed under the University of Illinois Open Source
> +// License. See LICENSE.TXT for details.
> +//
> +//===----------------------------------------------------------------------===//
> +//
> +// This class is used to customize machine-specific reciprocal estimate code
> +// generation in a target-independent way.
> +// If a target does not support operations in this specification, then code
> +// generation will default to using supported operations.
> +//
> +//===----------------------------------------------------------------------===//
> +
> +#include "llvm/ADT/StringRef.h"
> +#include "llvm/ADT/STLExtras.h"
> +#include "llvm/Support/ErrorHandling.h"
> +#include "llvm/Target/TargetRecip.h"
> +#include <map>
> +
> +using namespace llvm;
> +
> +// These are the names of the individual reciprocal operations. These are
> +// the key strings for queries and command-line inputs.
> +// In addition, the command-line interface recognizes the global parameters
> +// "all", "none", and "default".
> +static const char *RecipOps[] = {
> + "divd",
> + "divf",
> + "vec-divd",
> + "vec-divf",
> + "sqrtd",
> + "sqrtf",
> + "vec-sqrtd",
> + "vec-sqrtf",
> +};
> +
> +// The uninitialized state is needed for the enabled settings and refinement
> +// steps because custom settings may arrive via the command-line before target
> +// defaults are set.
> +TargetRecip::TargetRecip() {
> + unsigned NumStrings = llvm::array_lengthof(RecipOps);
> + for (unsigned i = 0; i < NumStrings; ++i)
> + RecipMap.insert(std::make_pair(RecipOps[i], RecipParams()));
> +}
> +
> +static bool parseRefinementStep(const StringRef &In, size_t &Position,
> + uint8_t &Value) {
> + const char RefStepToken = ':';
> + Position = In.find(RefStepToken);
> + if (Position == StringRef::npos)
> + return false;
> +
> + StringRef RefStepString = In.substr(Position + 1);
> + // Allow exactly one numeric character for the additional refinement
> + // step parameter.
> + if (RefStepString.size() == 1) {
> + char RefStepChar = RefStepString[0];
> + if (RefStepChar >= '0' && RefStepChar <= '9') {
> + Value = RefStepChar - '0';
> + return true;
> + }
> + }
> + report_fatal_error("Invalid refinement step for -recip.");
> +}
> +
> +bool TargetRecip::parseGlobalParams(const std::string &Arg) {
> + StringRef ArgSub = Arg;
> +
> + // Look for an optional setting of the number of refinement steps needed
> + // for this type of reciprocal operation.
> + size_t RefPos;
> + uint8_t RefSteps;
> + StringRef RefStepString;
> + if (parseRefinementStep(ArgSub, RefPos, RefSteps)) {
> + // Split the string for further processing.
> + RefStepString = ArgSub.substr(RefPos + 1);
> + ArgSub = ArgSub.substr(0, RefPos);
> + }
> + bool Enable;
> + bool UseDefaults;
> + if (ArgSub == "all") {
> + UseDefaults = false;
> + Enable = true;
> + } else if (ArgSub == "none") {
> + UseDefaults = false;
> + Enable = false;
> + } else if (ArgSub == "default") {
> + UseDefaults = true;
> + } else {
> + // Any other string is invalid or an individual setting.
> + return false;
> + }
> +
> + // All enable values will be initialized to target defaults if 'default' was
> + // specified.
> + if (!UseDefaults)
> + for (auto &KV : RecipMap)
> + KV.second.Enabled = Enable;
> +
> + // Custom refinement count was specified with all, none, or default.
> + if (!RefStepString.empty())
> + for (auto &KV : RecipMap)
> + KV.second.RefinementSteps = RefSteps;
> +
> + return true;
> +}
> +
> +void TargetRecip::parseIndividualParams(const std::vector<std::string> &Args) {
> + static const char DisabledPrefix = '!';
> + unsigned NumArgs = Args.size();
> +
> + for (unsigned i = 0; i != NumArgs; ++i) {
> + StringRef Val = Args[i];
> +
> + bool IsDisabled = Val[0] == DisabledPrefix;
> + // Ignore the disablement token for string matching.
> + if (IsDisabled)
> + Val = Val.substr(1);
> +
> + size_t RefPos;
> + uint8_t RefSteps;
> + StringRef RefStepString;
> + if (parseRefinementStep(Val, RefPos, RefSteps)) {
> + // Split the string for further processing.
> + RefStepString = Val.substr(RefPos + 1);
> + Val = Val.substr(0, RefPos);
> + }
> +
> + RecipIter Iter = RecipMap.find(Val);
> + if (Iter == RecipMap.end()) {
> + // Try again specifying float suffix.
> + Iter = RecipMap.find(Val.str() + 'f');
> + if (Iter == RecipMap.end()) {
> + Iter = RecipMap.find(Val.str() + 'd');
> + assert(Iter == RecipMap.end() && "Float entry missing from map");
> + report_fatal_error("Invalid option for -recip.");
> + }
> +
> + // The option was specified without a float or double suffix.
> + if (RecipMap[Val.str() + 'd'].Enabled != Uninitialized) {
> + // Make sure that the double entry was not already specified.
> + // The float entry will be checked below.
> + report_fatal_error("Duplicate option for -recip.");
> + }
> + }
> +
> + if (Iter->second.Enabled != Uninitialized)
> + report_fatal_error("Duplicate option for -recip.");
> +
> + // Mark the matched option as found. Do not allow duplicate specifiers.
> + Iter->second.Enabled = !IsDisabled;
> + if (!RefStepString.empty())
> + Iter->second.RefinementSteps = RefSteps;
> +
> + // If the precision was not specified, the double entry is also initialized.
> + if (Val.back() != 'f' && Val.back() != 'd') {
> + RecipMap[Val.str() + 'd'].Enabled = !IsDisabled;
> + if (!RefStepString.empty())
> + RecipMap[Val.str() + 'd'].RefinementSteps = RefSteps;
> + }
> + }
> +}
> +
> +TargetRecip::TargetRecip(const std::vector<std::string> &Args) :
> + TargetRecip() {
> + unsigned NumArgs = Args.size();
> +
> + // Check if "all", "default", or "none" was specified.
> + if (NumArgs == 1 && parseGlobalParams(Args[0]))
> + return;
> +
> + parseIndividualParams(Args);
> +}
> +
> +bool TargetRecip::isEnabled(const StringRef &Key) const {
> + ConstRecipIter Iter = RecipMap.find(Key);
> + assert(Iter != RecipMap.end() && "Unknown name for reciprocal map");
> + assert(Iter->second.Enabled != Uninitialized &&
> + "Enablement setting was not initialized");
> + return Iter->second.Enabled;
> +}
> +
> +unsigned TargetRecip::getRefinementSteps(const StringRef &Key) const {
> + ConstRecipIter Iter = RecipMap.find(Key);
> + assert(Iter != RecipMap.end() && "Unknown name for reciprocal map");
> + assert(Iter->second.RefinementSteps != Uninitialized &&
> + "Refinement step setting was not initialized");
> + return Iter->second.RefinementSteps;
> +}
> +
> +/// Custom settings (previously initialized values) override target defaults.
> +void TargetRecip::setDefaults(const StringRef &Key, bool Enable,
> + unsigned RefSteps) {
> + if (Key == "all") {
> + for (auto &KV : RecipMap) {
> + RecipParams &RP = KV.second;
> + if (RP.Enabled == Uninitialized)
> + RP.Enabled = Enable;
> + if (RP.RefinementSteps == Uninitialized)
> + RP.RefinementSteps = RefSteps;
> + }
> + } else {
> + RecipParams &RP = RecipMap[Key];
> + if (RP.Enabled == Uninitialized)
> + RP.Enabled = Enable;
> + if (RP.RefinementSteps == Uninitialized)
> + RP.RefinementSteps = RefSteps;
> + }
> +}
> +
> +bool TargetRecip::operator==(const TargetRecip &Other) const {
> + for (const auto &KV : RecipMap) {
> + const StringRef &Op = KV.first;
> + const RecipParams &RP = KV.second;
> + const RecipParams &OtherRP = Other.RecipMap.find(Op)->second;
> + if (RP.RefinementSteps != OtherRP.RefinementSteps)
> + return false;
> + if (RP.Enabled != OtherRP.Enabled)
> + return false;
> + }
> + return true;
> +}
>
> Modified: llvm/trunk/lib/Target/X86/X86.td
> URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Target/X86/X86.td?rev=239001&r1=239000&r2=239001&view=diff
> ==============================================================================
> --- llvm/trunk/lib/Target/X86/X86.td (original)
> +++ llvm/trunk/lib/Target/X86/X86.td Wed Jun 3 20:32:35 2015
> @@ -190,10 +190,6 @@ def FeatureSlowLEA : SubtargetFeature<"s
> "LEA instruction with certain arguments is slow">;
> def FeatureSlowIncDec : SubtargetFeature<"slow-incdec", "SlowIncDec", "true",
> "INC and DEC instructions are slower than ADD and SUB">;
> -def FeatureUseSqrtEst : SubtargetFeature<"use-sqrt-est", "UseSqrtEst", "true",
> - "Use RSQRT* to optimize square root calculations">;
> -def FeatureUseRecipEst : SubtargetFeature<"use-recip-est", "UseReciprocalEst",
> - "true", "Use RCP* to optimize division calculations">;
> def FeatureSoftFloat
> : SubtargetFeature<"soft-float", "UseSoftFloat", "true",
> "Use software floating point features.">;
> @@ -446,7 +442,7 @@ def : ProcessorModel<"btver2", BtVer2Mod
> FeaturePRFCHW, FeatureAES, FeaturePCLMUL,
> FeatureBMI, FeatureF16C, FeatureMOVBE,
> FeatureLZCNT, FeaturePOPCNT, FeatureFastUAMem,
> - FeatureSlowSHLD, FeatureUseSqrtEst, FeatureUseRecipEst]>;
> + FeatureSlowSHLD]>;
>
> // TODO: We should probably add 'FeatureFastUAMem' to all of the AMD chips.
>
>
> Modified: llvm/trunk/lib/Target/X86/X86ISelLowering.cpp
> URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Target/X86/X86ISelLowering.cpp?rev=239001&r1=239000&r2=239001&view=diff
> ==============================================================================
> --- llvm/trunk/lib/Target/X86/X86ISelLowering.cpp (original)
> +++ llvm/trunk/lib/Target/X86/X86ISelLowering.cpp Wed Jun 3 20:32:35 2015
> @@ -67,12 +67,6 @@ static cl::opt<bool> ExperimentalVectorW
> "rather than promotion."),
> cl::Hidden);
>
> -static cl::opt<int> ReciprocalEstimateRefinementSteps(
> - "x86-recip-refinement-steps", cl::init(1),
> - cl::desc("Specify the number of Newton-Raphson iterations applied to the "
> - "result of the hardware reciprocal estimate instruction."),
> - cl::NotHidden);
> -
> // Forward declarations.
> static SDValue getMOVL(SelectionDAG &DAG, SDLoc dl, EVT VT, SDValue V1,
> SDValue V2);
> @@ -13006,29 +13000,31 @@ SDValue X86TargetLowering::getRsqrtEstim
> DAGCombinerInfo &DCI,
> unsigned &RefinementSteps,
> bool &UseOneConstNR) const {
> - // FIXME: We should use instruction latency models to calculate the cost of
> - // each potential sequence, but this is very hard to do reliably because
> - // at least Intel's Core* chips have variable timing based on the number of
> - // significant digits in the divisor and/or sqrt operand.
> - if (!Subtarget->useSqrtEst())
> - return SDValue();
> -
> EVT VT = Op.getValueType();
> + const char *RecipOp;
>
> - // SSE1 has rsqrtss and rsqrtps.
> + // SSE1 has rsqrtss and rsqrtps. AVX adds a 256-bit variant for rsqrtps.
> // TODO: Add support for AVX512 (v16f32).
> // It is likely not profitable to do this for f64 because a double-precision
> // rsqrt estimate with refinement on x86 prior to FMA requires at least 16
> // instructions: convert to single, rsqrtss, convert back to double, refine
> // (3 steps = at least 13 insts). If an 'rsqrtsd' variant was added to the ISA
> // along with FMA, this could be a throughput win.
> - if ((Subtarget->hasSSE1() && (VT == MVT::f32 || VT == MVT::v4f32)) ||
> - (Subtarget->hasAVX() && VT == MVT::v8f32)) {
> - RefinementSteps = 1;
> - UseOneConstNR = false;
> - return DCI.DAG.getNode(X86ISD::FRSQRT, SDLoc(Op), VT, Op);
> - }
> - return SDValue();
> + if (VT == MVT::f32 && Subtarget->hasSSE1())
> + RecipOp = "sqrtf";
> + else if ((VT == MVT::v4f32 && Subtarget->hasSSE1()) ||
> + (VT == MVT::v8f32 && Subtarget->hasAVX()))
> + RecipOp = "vec-sqrtf";
> + else
> + return SDValue();
> +
> + TargetRecip Recips = DCI.DAG.getTarget().Options.Reciprocals;
> + if (!Recips.isEnabled(RecipOp))
> + return SDValue();
> +
> + RefinementSteps = Recips.getRefinementSteps(RecipOp);
> + UseOneConstNR = false;
> + return DCI.DAG.getNode(X86ISD::FRSQRT, SDLoc(Op), VT, Op);
> }
>
> /// The minimum architected relative accuracy is 2^-12. We need one
> @@ -13036,15 +13032,9 @@ SDValue X86TargetLowering::getRsqrtEstim
> SDValue X86TargetLowering::getRecipEstimate(SDValue Op,
> DAGCombinerInfo &DCI,
> unsigned &RefinementSteps) const {
> - // FIXME: We should use instruction latency models to calculate the cost of
> - // each potential sequence, but this is very hard to do reliably because
> - // at least Intel's Core* chips have variable timing based on the number of
> - // significant digits in the divisor.
> - if (!Subtarget->useReciprocalEst())
> - return SDValue();
> -
> EVT VT = Op.getValueType();
> -
> + const char *RecipOp;
> +
> // SSE1 has rcpss and rcpps. AVX adds a 256-bit variant for rcpps.
> // TODO: Add support for AVX512 (v16f32).
> // It is likely not profitable to do this for f64 because a double-precision
> @@ -13052,12 +13042,20 @@ SDValue X86TargetLowering::getRecipEstim
> // 15 instructions: convert to single, rcpss, convert back to double, refine
> // (3 steps = 12 insts). If an 'rcpsd' variant was added to the ISA
> // along with FMA, this could be a throughput win.
> - if ((Subtarget->hasSSE1() && (VT == MVT::f32 || VT == MVT::v4f32)) ||
> - (Subtarget->hasAVX() && VT == MVT::v8f32)) {
> - RefinementSteps = ReciprocalEstimateRefinementSteps;
> - return DCI.DAG.getNode(X86ISD::FRCP, SDLoc(Op), VT, Op);
> - }
> - return SDValue();
> + if (VT == MVT::f32 && Subtarget->hasSSE1())
> + RecipOp = "divf";
> + else if ((VT == MVT::v4f32 && Subtarget->hasSSE1()) ||
> + (VT == MVT::v8f32 && Subtarget->hasAVX()))
> + RecipOp = "vec-divf";
> + else
> + return SDValue();
> +
> + TargetRecip Recips = DCI.DAG.getTarget().Options.Reciprocals;
> + if (!Recips.isEnabled(RecipOp))
> + return SDValue();
> +
> + RefinementSteps = Recips.getRefinementSteps(RecipOp);
> + return DCI.DAG.getNode(X86ISD::FRCP, SDLoc(Op), VT, Op);
> }
>
> /// If we have at least two divisions that use the same divisor, convert to
>
> Modified: llvm/trunk/lib/Target/X86/X86Subtarget.cpp
> URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Target/X86/X86Subtarget.cpp?rev=239001&r1=239000&r2=239001&view=diff
> ==============================================================================
> --- llvm/trunk/lib/Target/X86/X86Subtarget.cpp (original)
> +++ llvm/trunk/lib/Target/X86/X86Subtarget.cpp Wed Jun 3 20:32:35 2015
> @@ -274,8 +274,6 @@ void X86Subtarget::initializeEnvironment
> LEAUsesAG = false;
> SlowLEA = false;
> SlowIncDec = false;
> - UseSqrtEst = false;
> - UseReciprocalEst = false;
> stackAlignment = 4;
> // FIXME: this is a known good value for Yonah. How about others?
> MaxInlineSizeThreshold = 128;
>
> Modified: llvm/trunk/lib/Target/X86/X86Subtarget.h
> URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Target/X86/X86Subtarget.h?rev=239001&r1=239000&r2=239001&view=diff
> ==============================================================================
> --- llvm/trunk/lib/Target/X86/X86Subtarget.h (original)
> +++ llvm/trunk/lib/Target/X86/X86Subtarget.h Wed Jun 3 20:32:35 2015
> @@ -190,16 +190,6 @@ protected:
> /// True if INC and DEC instructions are slow when writing to flags
> bool SlowIncDec;
>
> - /// Use the RSQRT* instructions to optimize square root calculations.
> - /// For this to be profitable, the cost of FSQRT and FDIV must be
> - /// substantially higher than normal FP ops like FADD and FMUL.
> - bool UseSqrtEst;
> -
> - /// Use the RCP* instructions to optimize FP division calculations.
> - /// For this to be profitable, the cost of FDIV must be
> - /// substantially higher than normal FP ops like FADD and FMUL.
> - bool UseReciprocalEst;
> -
> /// Processor has AVX-512 PreFetch Instructions
> bool HasPFI;
>
> @@ -380,8 +370,6 @@ public:
> bool LEAusesAG() const { return LEAUsesAG; }
> bool slowLEA() const { return SlowLEA; }
> bool slowIncDec() const { return SlowIncDec; }
> - bool useSqrtEst() const { return UseSqrtEst; }
> - bool useReciprocalEst() const { return UseReciprocalEst; }
> bool hasCDI() const { return HasCDI; }
> bool hasPFI() const { return HasPFI; }
> bool hasERI() const { return HasERI; }
>
> Modified: llvm/trunk/lib/Target/X86/X86TargetMachine.cpp
> URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Target/X86/X86TargetMachine.cpp?rev=239001&r1=239000&r2=239001&view=diff
> ==============================================================================
> --- llvm/trunk/lib/Target/X86/X86TargetMachine.cpp (original)
> +++ llvm/trunk/lib/Target/X86/X86TargetMachine.cpp Wed Jun 3 20:32:35 2015
> @@ -105,6 +105,13 @@ X86TargetMachine::X86TargetMachine(const
> if (Subtarget.isTargetWin64())
> this->Options.TrapUnreachable = true;
>
> + // TODO: By default, all reciprocal estimate operations are off because
> + // that matches the behavior before TargetRecip was added (except for btver2
> + // which used subtarget features to enable this type of codegen).
> + // We should change this to match GCC behavior where everything but
> + // scalar division estimates are turned on by default with -ffast-math.
> + this->Options.Reciprocals.setDefaults("all", false, 1);
> +
> initAsmInfo();
> }
>
>
> Modified: llvm/trunk/test/CodeGen/X86/recip-fastmath.ll
> URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/CodeGen/X86/recip-fastmath.ll?rev=239001&r1=239000&r2=239001&view=diff
> ==============================================================================
> --- llvm/trunk/test/CodeGen/X86/recip-fastmath.ll (original)
> +++ llvm/trunk/test/CodeGen/X86/recip-fastmath.ll Wed Jun 3 20:32:35 2015
> @@ -1,6 +1,6 @@
> ; RUN: llc < %s -mtriple=x86_64-unknown-unknown -mattr=sse2 | FileCheck %s
> -; RUN: llc < %s -mtriple=x86_64-unknown-unknown -mattr=avx,use-recip-est | FileCheck %s --check-prefix=RECIP
> -; RUN: llc < %s -mtriple=x86_64-unknown-unknown -mattr=avx,use-recip-est -x86-recip-refinement-steps=2 | FileCheck %s --check-prefix=REFINE
> +; RUN: llc < %s -mtriple=x86_64-unknown-unknown -mattr=avx -recip=divf,vec-divf | FileCheck %s --check-prefix=RECIP
> +; RUN: llc < %s -mtriple=x86_64-unknown-unknown -mattr=avx -recip=divf:2,vec-divf:2 | FileCheck %s --check-prefix=REFINE
>
> ; If the target's divss/divps instructions are substantially
> ; slower than rcpss/rcpps with a Newton-Raphson refinement,
>
> Modified: llvm/trunk/test/CodeGen/X86/sqrt-fastmath.ll
> URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/CodeGen/X86/sqrt-fastmath.ll?rev=239001&r1=239000&r2=239001&view=diff
> ==============================================================================
> --- llvm/trunk/test/CodeGen/X86/sqrt-fastmath.ll (original)
> +++ llvm/trunk/test/CodeGen/X86/sqrt-fastmath.ll Wed Jun 3 20:32:35 2015
> @@ -1,5 +1,5 @@
> ; RUN: llc < %s -mtriple=x86_64-unknown-unknown -mattr=sse2 | FileCheck %s
> -; RUN: llc < %s -mtriple=x86_64-unknown-unknown -mattr=avx,use-sqrt-est | FileCheck %s --check-prefix=ESTIMATE
> +; RUN: llc < %s -mtriple=x86_64-unknown-unknown -mattr=avx -recip=sqrtf,vec-sqrtf | FileCheck %s --check-prefix=ESTIMATE
>
> declare double @__sqrt_finite(double) #0
> declare float @__sqrtf_finite(float) #0
>
>
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