Developer Guide and Reference

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ID 767253
Date 10/31/2024
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Document Table of Contents
Document Table of Contents x
Developer Guide and Reference
Developer Guide and Reference x
Intel® oneAPI DPC++/C++ Compiler Introduction Compiler Setup Compiler Reference Compilation Optimization and Programming Compatibility and Portability Notices and Disclaimers
Intel® oneAPI DPC++/C++ Compiler Introduction x
Get Help and Support Related Information
Compiler Setup x
Use the Command Line Use Eclipse Use Microsoft Visual Studio
Use the Command Line x
Specify Component Locations Invoke the Compiler Use the Command Line on Windows File Extensions Use Makefiles for Compilation Use CMake with the Compiler Use Compiler Options Specify Compiler Files Convert Projects to Use a Selected Compiler
Use Eclipse x
Add the Compiler to Eclipse Multiversion Compiler Support Use Cheat Sheets Create a Simple Eclipse Project Makefiles Use Intel Libraries with Eclipse
Use Microsoft Visual Studio x
Create a New Project Use the Intel® oneAPI DPC++/C++ Compiler Select the Compiler Version Specify a Base Platform Toolset Use Property Pages Use Intel® Libraries with Microsoft Visual Studio* Include MPI Support Use Code Coverage in Microsoft Visual Studio* Use Profile Guided Optimization in Microsoft Visual Studio* Optimization Reports in Microsoft Visual Studio* Dialog Box Help
Dialog Box Help x
Use Intel® oneAPI DPC++/C++ Compiler dialog box Hardware Profile-Guided Optimization dialog box Options: Compilers dialog box Options: Intel Libraries for oneAPI dialog box Options: Converter dialog box Options: Optimization Reports dialog box Options: Profile Guided Optimization dialog box Profile Guided Optimization dialog box Options: Code Coverage dialog box Code Coverage dialog box Code Coverage Settings dialog box
Compiler Reference x
C/C++/SYCL Calling Conventions Compiler Options Floating-Point Operations Attributes Intrinsics Libraries Macros Pragmas Syntactic and Semantic Errors
Compiler Options x
Alphabetical Option List General Rules for Compiler Options What Appears in the Compiler Option Descriptions Optimization Options Advanced Optimization Options Code Generation Options Offload Compilation, OpenMP*, and Parallel Processing Options Interprocedural Optimization Options Profile Guided Optimization Options Optimization Report Options Floating-Point Options Inlining Options Output, Debug, and Precompiled Header Options Preprocessor Options Component Control Options Language Options Data Options Compiler Diagnostic Options Compatibility Options Linking or Linker Options Miscellaneous Options Deprecated and Removed Compiler Options Display Option Information Alternate Compiler Options Portability and GCC-Compatible Warning Options
Optimization Options x
fast fbuiltin, Oi foptimize-sibling-calls GF nolib-inline O Od Ofast Os Ot Ox
Advanced Optimization Options x
ffreestanding, Qfreestanding fjump-tables fvec-allow-scalar-stores, Qvec-allow-scalar-stores fvec-peel-loops, Qvec-peel-loops fvec-remainder-loops, Qvec-remainder-loops fvec-with-mask, Qvec-with-mask ipp-link, Qipp-link mno-gather, Qgather- mno-scatter, Qscatter- qactypes, Qactypes qdaal, Qdaal qipp, Qipp qmkl, Qmkl qmkl-ilp64, Qmkl-ilp64 qmkl-sycl-impl, Qmkl-sycl-impl qopt-assume-no-loop-carried-dep, Qopt-assume-no-loop-carried-dep qopt-dword-index-for-array-of-structs, Qopt-dword-index-for-array-of-structs qopt-dynamic-align, Qopt-dynamic-align qopt-for-throughput, Qopt-for-throughput qopt-mem-layout-trans, Qopt-mem-layout-trans qopt-multiple-gather-scatter-by-shuffles, Qopt-multiple-gather-scatter-by-shuffles qopt-prefetch, Qopt-prefetch qopt-prefetch-distance, Qopt-prefetch-distance qopt-prefetch-loads-only, Qopt-prefetch-loads-only qopt-streaming-stores, Qopt-streaming-stores qopt-zmm-usage, Qopt-zmm-usage qtbb, Qtbb unroll, Qunroll vec, Qvec vec-threshold, Qvec-threshold vecabi, Qvecabi
Code Generation Options x
arch ax, Qax EH fasynchronous-unwind-tables fcf-protection, Qcf-protection fdata-sections, Gw fexceptions ffunction-sections, Gy fomit-frame-pointer Gd GR guard Gv m, Qm m64, Qm64 m80387 march masm mauto-arch, Qauto-arch mbranches-within-32B-boundaries, Qbranches-within-32B-boundaries mintrinsic-promote, Qintrinsic-promote momit-leaf-frame-pointer mtune, tune regcall, Qregcall x, Qx xHost, QxHost
Offload Compilation, OpenMP*, and Parallel Processing Options x
device-math-lib fintelfpga fiopenmp, Qiopenmp flink-huge-device-code fno-sycl-libspirv fopenmp fopenmp-concurrent-host-device-compile, Qopenmp-concurrent-host-device-compile fopenmp-declare-target-scalar-defaultmap, Qopenmp-declare-target-scalar-defaultmap fopenmp-device-code-split, Qopenmp-device-code-split fopenmp-device-lib fopenmp-device-link, Qopenmp-device-link fopenmp-max-parallel-link-jobs, Qopenmp-max-parallel-link-jobs fopenmp-offload-mandatory, Qopenmp-offload-mandatory fopenmp-target-buffers, Qopenmp-target-buffers fopenmp-target-default-sub-group-size, Qopenmp-target-default-sub-group-size fopenmp-target-loopopt, Qopenmp-target-loopopt fopenmp-target-simd, Qopenmp-target-simd fopenmp-targets, Qopenmp-targets fsycl fsycl-add-default-spec-consts-image fsycl-allow-device-dependencies fsycl-dead-args-optimization fsycl-device-code-split fsycl-device-lib fsycl-device-obj fsycl-device-only fsycl-early-optimizations fsycl-enable-function-pointers fsycl-esimd-force-stateless-mem fsycl-explicit-simd fsycl-force-target fsycl-fp64-conv-emu fsycl-help fsycl-host-compiler fsycl-host-compiler-options fsycl-id-queries-fit-in-int fsycl-instrument-device-code fsycl-link fsycl-max-parallel-link-jobs fsycl-optimize-non-user-code fsycl-pstl-offload fsycl-rdc fsycl-remove-unused-external-funcs fsycl-targets fsycl-unnamed-lambda fsycl-use-bitcode ftarget-compile-fast ftarget-export-symbols ftarget-register-alloc-mode, Qtarget-register-alloc-mode nolibsycl qopenmp, Qopenmp qopenmp-link qopenmp-simd, Qopenmp-simd qopenmp-stubs, Qopenmp-stubs reuse-exe Wno-sycl-strict Xopenmp-target Xs Xsycl-target
Interprocedural Optimization Options x
flto ipo, Qipo
Profile Guided Optimization Options x
fprofile-dwo-dir fprofile-ml-use fprofile-sample-generate fprofile-sample-use
Optimization Report Options x
qopt-report, Qopt-report qopt-report-file, Qopt-report-file qopt-report-names, Qopt-report-names qopt-report-phase, Qopt-report-phase qopt-report-stdout, Qopt-report-stdout
Floating-Point Options x
ffp-accuracy, Qfp-accuracy ffp-contract fimf-absolute-error, Qimf-absolute-error fimf-accuracy-bits, Qimf-accuracy-bits fimf-arch-consistency, Qimf-arch-consistency fimf-domain-exclusion, Qimf-domain-exclusion fimf-max-error, Qimf-max-error fimf-precision, Qimf-precision fimf-use-svml, Qimf-use-svml fma, Qfma fp-model, fp fp-speculation, Qfp-speculation ftz, Qftz pc, Qpc
Inlining Options x
fgnu89-inline finline finline-functions inline-forceinline, Qinline-forceinline
Output, Debug, and Precompiled Header Options x
c debug (Linux*) debug (Windows*) Fa fasm-blocks Fe Fo Fp fsystem-debug fverbose-asm g gdwarf grecord-gcc-switches gsplit-dwarf o S use-msasm Y- Yc Yu Zi, Z7, ZI
Preprocessor Options x
B C D dD, QdD dM, QdM E EP FI H, QH I idirafter imacros iprefix iquote isystem iwithprefix iwithprefixbefore M, QM MD, QMD MF, QMF MG, QMG MM, QMM MMD, QMMD MQ, QMQ MT, QMT nostdinc++ P TP U undef X
Component Control Options x
Qoption
Language Options x
ansi fno-gnu-keywords fno-operator-names fno-rtti fpermissive fshort-enums fsyntax-only, Zs funsigned-char, J std, Qstd strict-ansi vd vmg x (type option) Zc Zg Zp
Data Options x
fcommon fkeep-static-consts, Qkeep-static-consts fmaintain-32-byte-stack-align, Qmaintain-32-byte-stack-align fmath-errno fpack-struct fpic fpie fstack-protector fstack-security-check fvisibility fzero-initialized-in-bss, Qzero-initialized-in-bss GA Gs GS mcmodel Qlong-double
Compiler Diagnostic Options x
w W Wabi Wall Wcheck-unicode-security Wcomment Wdeprecated Werror, WX Werror-all Wextra-tokens Wformat Wformat-security Wmain Wmissing-declarations Wmissing-prototypes Wpointer-arith Wreorder Wreturn-type Wshadow Wsign-compare Wstrict-aliasing Wstrict-prototypes Wtrigraphs Wuninitialized Wunknown-pragmas Wunused-function Wunused-variable Wwrite-strings
Compatibility Options x
gcc-toolchain vmv
Linking or Linker Options x
F (Windows*) fixed fortlib fuse-ld l L LD link MD MT nodefaultlibs no-intel-lib, Qno-intel-lib nostartfiles nostdlib pie pthread shared shared-intel shared-libgcc static static-intel static-libgcc static-libstdc++ T u (Linux*) v Wa Wl Wp Xlinker Zl
Miscellaneous Options x
dryrun dumpmachine dumpversion fpreview-breaking-changes help MP nologo save-temps, Qsave-temps showIncludes sox sysroot Tc TC Tp version
Floating-Point Operations x
Programming Tradeoffs in Floating-Point Applications Floating-Point Optimizations Denormal Numbers Floating-Point Environment Set the FTZ and DAZ Flags Tuning Performance IEEE Floating-Point Operations
Attributes x
align align_value allow_cpu_features code_align const cpu_dispatch, cpu_specific target
Libraries x
Create Libraries Use Intel Shared Libraries Manage Libraries Redistribute Libraries When Deploying Applications Resolve References to Shared Libraries Redistributable Library Considerations Intel's Memory Allocator Library SIMD Data Layout Templates Intel® C++ Class Libraries Intel's C++ Asynchronous I/O Extensions for Windows IEEE 754-2008 Binary Floating-Point Conformance Library Intel's Numeric String Conversion Library
SIMD Data Layout Templates x
Function Calls and Containers User-Level Interface Examples
Function Calls and Containers x
Construct an n_container Bounds
User-Level Interface x
SDLT Primitives soa1d_container aos1d_container n_container Bounds Accessors Proxy Objects Number Representation Indexes Convenience and Correctness
aos1d_container x
access_by
n_container x
Layouts Shape make_ n_container template function extent_d template function
Shape x
n_extent_generator
Bounds x
bounds_t sdlt::bounds Template Function n_bounds_t n_bounds_generator bounds_d Template Function
Accessors x
soa1d_container::accessor and aos1d_container::accessor soa1d_container::const_accessor and aos1d_container::const_accessor Accessor Concept
Proxy Objects x
Proxy ConstProxy
Number Representation x
aligned_offset fixed_offset
Indexes x
linear_index n_index_t n_index_generator index_d template function
Convenience and Correctness x
max_val min_val
Examples x
Efficiency with Structure of Arrays Example Complex SDLT Primitive Construction Example Forward Dependency Example Use of Offsets and Methods on a SDLT Primitive Example RGB to YUV Conversion Example
Intel® C++ Class Libraries x
C++ Classes and SIMD Operations Capabilities of C++ SIMD Classes Integer Vector Classes Floating-Point Vector Classes Classes Quick Reference Programming Example Intel's valarray Implementation
Integer Vector Classes x
Terms and Syntax Rules for Operators Assignment Operator Logical Operators Addition and Subtraction Operators Multiplication Operators Shift Operators Comparison Operators Conditional Select Operators Debug Operations Unpack Operators Pack Operators Clear MMX™ State Operator Integer Functions for Intel® Streaming SIMD Extensions Conversions between Fvec and Ivec
Floating-Point Vector Classes x
Fvec Syntax and Notation Data Alignment Conversions Constructors and Initialization Arithmetic Operators Minimum and Maximum Operators Logical Operators Compare Operators Conditional Select Operators for Fvec Classes Cacheability Support Operators Debug Operations Load and Store Operators Unpack Operators Move Mask Operators
Intel's C++ Asynchronous I/O Extensions for Windows x
Intel's C++ Asynchronous I/O Library for Windows Intel's C++ Asynchronous I/O Class for Windows
Intel's C++ Asynchronous I/O Library for Windows x
aio_read aio_write Example for aio_read and aio_write Functions aio_suspend Example for aio_suspend Function aio_error aio_return Example for aio_error and aio_return Functions aio_fsync aio_cancel Example for aio_cancel Function lio_listio Example for lio_listio Function Asynchronous I/O Function Errors
Intel's C++ Asynchronous I/O Class for Windows x
Template Class async_class get_last_operation_id wait get_status get_last_error get_error_operation_id stop_queue resume_queue clear_queue Example for Using async_class Template Class
IEEE 754-2008 Binary Floating-Point Conformance Library x
Intel® IEEE 754-2008 Binary Floating-Point Conformance Library and Usage Function List Homogeneous General-Computational Operations Functions General-Computational Operation Functions Quiet-Computational Operations Functions Signaling-Computational Operations Functions Non-Computational Operations Functions
Intel's Numeric String Conversion Library x
Use Intel's Numeric String Conversion Library Function List
Macros x
ISO Standard Predefined Macros Additional Predefined Macros Use Predefined Macros to Specify Intel® Compilers
Pragmas x
Intel-Specific Pragma Reference Supported OpenMP* Pragmas Pragmas Compatible with Other Compilers
Intel-Specific Pragma Reference x
block_loop/noblock_loop distribute_point inline, noinline, forceinline ivdep loop_count nofusion novector omp target variant dispatch ompx prefetch data prefetch/noprefetch unroll/nounroll unroll_and_jam/nounroll_and_jam vector
Compilation x
Compilation Overview Supported Environment Variables Pass Options to the Linker Specify Alternate Tools Use Configuration Files Use Response Files Global Symbols and Visibility Attributes for Linux* Save Compiler Information in Your Executable Link Debug Information Ahead of Time Compilation Device Offload Compilation Considerations Use a Third-Party Compiler as a Host Compiler for SYCL Code
Optimization and Programming x
OpenMP* Support SYCL* Support Compiler Sanitizers Intel® oneAPI Level Zero Vectorization Instrumented Profile-Guided Optimization Hardware Profile-Guided Optimization High-Level Optimization Interprocedural Optimization Methods to Optimize Code Size Optimization Reports Compiler Math Library SYCL* Device Library
OpenMP* Support x
Add OpenMP* Support Parallel Processing Model Worksharing Using OpenMP* Control Thread Allocation OpenMP* Library Support OpenMP* Contexts OpenMP* Offloading SPMD/SIMT and SIMD Models OpenMP* Advanced Issues OpenMP* Implementation-Defined Behaviors OpenMP* Examples
OpenMP* Library Support x
OpenMP* Runtime Library Routines Intel® Compiler Extension Routines to OpenMP* OpenMP* Support Libraries Use the OpenMP* Libraries Thread Affinity Interface OpenMP* Memory Spaces and Allocators
OpenMP* Contexts x
OpenMP* Context Selectors Score and Match Context Selectors
SYCL* Support x
SYCL* Extensions Redistribute Your SYCL* Application CUDA* to SYCL* Migration
Intel® oneAPI Level Zero x
Intel® oneAPI Level Zero Switch Intel® oneAPI Level Zero Backend Specification Programming with the Intel® oneAPI Level Zero Backend
Vectorization x
Automatic Vectorization Explicit Vector Programming
Automatic Vectorization x
Vectorization Programming Guidelines Use Automatic Vectorization Vectorization and Loops Loop Constructs
Explicit Vector Programming x
User-Mandated or SIMD Vectorization SIMD-Enabled Functions SIMD-Enabled Function Pointers Function Annotations and the SIMD Directive for Vectorization Explicit SIMD SYCL Extension
Interprocedural Optimization x
Use Interprocedural Optimization Performance Considerations Create a Library from IPO Objects Inline Expansion of Functions Select Routines for Inlining Inline Expansion of Library Functions Inlining and Function Preemption on Linux Developer-Directed Inline Expansion of User Functions See Also
Compiler Math Library x
Use the Compiler Math Library Math Function List Trigonometric Functions Hyperbolic Functions Exponential Functions Special Functions Nearest Integer Functions Remainder Functions Miscellaneous Functions Complex Functions C99 Macros
SYCL* Device Library x
Basic Arithmetic Operations and Simple Math Functions IMF Transcendental Math Functions
Basic Arithmetic Operations and Simple Math Functions x
Simple Integer Math Functions Basic Integer Arithmetic Operations Simple Arithmetic Operations with Rounding Mode Type Casting Functions for Floating-Point Numbers Type Casting Functions for Half-Precision Types Type Casting Functions for bfloat16 Type Simple Half-Precision Arithmetic Math Functions Half-Precision Comparison Functions
IMF Transcendental Math Functions x
IMF Device Library Usage Example IMF Device Library Function List IMF Device Library Trigonometric Functions IMF Device Library Hyperbolic Functions IMF Device Library Exponential Functions IMF Device Library Logarithmic Functions IMF Device Library Power Functions IMF Device Library Special Functions IMF Device Library Rounding Functions IMF Device Library Miscellaneous Functions
Compatibility and Portability x
Standards Conformance GCC Compatibility and Interoperability Microsoft Compatibility Port from Microsoft Visual C++* to the Intel® oneAPI DPC++/C++ Compiler Port from GCC* to the Intel® oneAPI DPC++/C++ Compiler
Port from Microsoft Visual C++* to the Intel® oneAPI DPC++/C++ Compiler x
Modify Your makefile Other Considerations
Port from GCC* to the Intel® oneAPI DPC++/C++ Compiler x
Modify Your makefile Other Considerations
Developer Guide and Reference

Inline Expansion of Functions

Inline function expansion does not require that the applications meet the criteria for whole program analysis normally required by IPO; so this optimization is one of the most important optimizations done in Interprocedural Optimization (IPO). For function calls that the compiler believes are frequently executed, the compiler often decides to replace the instructions of the call with code for the function itself.

In the compiler, inline function expansion is performed on relatively small user functions more often than on functions that are relatively large. This optimization improves application performance by performing the following:

  • Removing the need to set up parameters for a function call

  • Eliminating the function call branch

  • Propagating constants

Function inlining can improve execution time by removing the runtime overhead of function calls; however, function inlining can increase code size, code complexity, and compile times. In general, when you instruct the compiler to perform function inlining, the compiler can examine the source code in a much larger context, and the compiler can find more opportunities to apply optimizations.

CAUTION:

Using the Windows* options can, in some cases, significantly increase compile time and code size.

Select Routines for Inlining

The compiler attempts to select the routines whose inline expansions provide the greatest benefit to program performance. The selection is done using default heuristics.

When you use PGO with [Q]ipo, the compiler uses the following guidelines for applying heuristics:

  • The default heuristic focuses on the most frequently executed call sites, based on the profile information gathered for the program.

  • The default heuristic always inlines very small functions that meet the minimum inline criteria.

Use IPO with PGO

Combining IPO and PGO typically produces better results than using IPO alone. PGO produces dynamic profiling information that can usually provide better optimization opportunities than the static profiling information used in IPO.

The compiler uses characteristics of the source code to estimate which function calls are executed most frequently. It applies these estimates to the PGO-based guidelines described above. The estimation of frequency, based on static characteristics of the source, is not always accurate.

Inline Expansion of Library Functions

By default, the compiler automatically inlines (expands) a number of standard and math library functions at the point of the call to that function, which usually results in faster computation.

Many routines in the libirc, libm, or the svml library are more highly optimized for Intel microprocessors than for non-Intel microprocessors.

The -fno-builtin (Linux*) or the /Qno-builtin-<name> and /Oi- (Windows*) options disable inlining for intrinsic functions and disable the by-name recognition support of intrinsic functions and the resulting optimizations. The /Qno-builtin-<name> option provides the ability to disable inlining for intrinsic functions, fine-tuning the functionality of the /Oi- option, which disables almost all intrinsic functions when used. Use these options if you redefine standard library routines with your own version and your version of the routine has the same name as the standard library routine.

Inlining and Function Preemption on Linux

You must specify fpic to use function preemption. By default the compiler does not generate the position-independent code needed for preemption.

Developer-Directed Inline Expansion of User Functions

In addition to the options that support compiler directed inline expansion of user functions, the compiler also provides compiler options and pragmas that allow you to more precisely direct when and if inline function expansion should occur.

The compiler measures the relative size of a routine in an abstract value of intermediate language units, which is approximately equivalent to the number of instructions that will be generated. The compiler uses the intermediate language unit estimates to classify routines and functions as relatively small, medium, or large functions. The compiler then uses the estimates to determine when to inline a function; if the minimum criteria for inlining is met and all other things are equal, the compiler has an affinity for inlining relatively small functions and not inlining relative large functions.

Typically, the compiler targets functions that have been marked for inlining based on the following:

  • Inlining keywords: Tells the compiler to inline the specified function. For example, __inline, __forceinline.
  • Procedure-specific inlining pragmas: Tells the compiler to inline calls within the targeted procedure if it is legal to do so. For example,#pragma inline or #pragma forceinline .
  • GCC function attributes for inlining: Tells the compiler to inline the function even when no optimization level is specified. For example, __attribute__((always_inline)).

Parent topic: Interprocedural Optimization

See Also

fbuiltin, Oi compiler option
fpic compiler option
ipo, Qipo compiler option
debug (Linux* OS) compiler option
debug (Windows* OS) compiler option
Zi, Z7, Zl compiler option
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