Intel C++ Compiler is a group of
CC is a general-purpose computer programming language developed between 1969 and 1973 by Dennis Ritchie at the Bell Telephone Laboratories for use with the Unix operating system....
and
C++C++ is a statically typed, free-form, multi-paradigm, compiled, general-purpose programming language. It is regarded as an intermediate-level language, as it comprises a combination of both high-level and low-level language features. It was developed by Bjarne Stroustrup starting in 1979 at Bell...
compilerA compiler is a computer program that transforms source code written in a programming language into another computer language...
s from
Intel CorporationIntel Corporation is an American multinational semiconductor chip maker corporation headquartered in Santa Clara, California, United States and the world's largest semiconductor chip maker, based on revenue. It is the inventor of the x86 series of microprocessors, the processors found in most...
available for GNU/Linux,
Mac OS XMac OS X is a series of Unix-based operating systems and graphical user interfaces developed, marketed, and sold by Apple Inc. Since 2002, has been included with all new Macintosh computer systems...
, and
Microsoft WindowsMicrosoft Windows is a series of operating systems produced by Microsoft.Microsoft introduced an operating environment named Windows on November 20, 1985 as an add-on to MS-DOS in response to the growing interest in graphical user interfaces . Microsoft Windows came to dominate the world's personal...
.
Intel supports compilation for its
IA-32IA-32 , also known as x86-32, i386 or x86, is the CISC instruction-set architecture of Intel's most commercially successful microprocessors, and was first implemented in the Intel 80386 as a 32-bit extension of x86 architecture...
and Intel 64 processors and certain non-Intel but compatible processors, such as AMD processors. Developers should check system requirements. The Intel C++ Compiler for IA-32 and Intel 64 features an automatic vectorizer that can generate
SSEIn computing, Streaming SIMD Extensions is a SIMD instruction set extension to the x86 architecture, designed by Intel and introduced in 1999 in their Pentium III series processors as a reply to AMD's 3DNow! . SSE contains 70 new instructions, most of which work on single precision floating point...
,
SSE2SSE2, Streaming SIMD Extensions 2, is one of the Intel SIMD processor supplementary instruction sets first introduced by Intel with the initial version of the Pentium 4 in 2001. It extends the earlier SSE instruction set, and is intended to fully supplant MMX. Intel extended SSE2 to create SSE3...
,
SSE3SSE3, Streaming SIMD Extensions 3, also known by its Intel code name Prescott New Instructions , is the third iteration of the SSE instruction set for the IA-32 architecture. Intel introduced SSE3 in early 2004 with the Prescott revision of their Pentium 4 CPU...
,
SSSE3Supplemental Streaming SIMD Extensions 3 is a SIMD instruction set created by Intel and is the fourth iteration of the SSE technology.- History :...
,
SSE4SSE4 is a CPU instruction set used in the Intel Core microarchitecture and AMD K10 . It was announced on 27 September 2006 at the Fall 2006 Intel Developer Forum, with vague details in a white paper; more precise details of 47 instructions became available at the Spring 2007 Intel Developer Forum...
and
AVXAdvanced Vector Extensions is an extension to the x86 instruction set architecture for microprocessors from Intel and AMD proposed by Intel in March 2008 and first supported by Intel with the Westmere processor shipping in Q1 2011 and now by AMD with the Bulldozer processor shipping in Q3 2011.AVX...
SIMDSingle instruction, multiple data , is a class of parallel computers in Flynn's taxonomy. It describes computers with multiple processing elements that perform the same operation on multiple data simultaneously...
instructions, the
embeddedAn embedded system is a computer system designed for specific control functions within a larger system. often with real-time computing constraints. It is embedded as part of a complete device often including hardware and mechanical parts. By contrast, a general-purpose computer, such as a personal...
variant for Intel Wireless MMX and MMX 2. Since its introduction, the Intel C++ Compiler for
IA-32IA-32 , also known as x86-32, i386 or x86, is the CISC instruction-set architecture of Intel's most commercially successful microprocessors, and was first implemented in the Intel 80386 as a 32-bit extension of x86 architecture...
has greatly increased adoption of SSE2 in Windows application development.
Intel C++ Compiler further supports both
OpenMPOpenMP is an API that supports multi-platform shared memory multiprocessing programming in C, C++, and Fortran, on most processor architectures and operating systems, including Linux, Unix, AIX, Solaris, Mac OS X, and Microsoft Windows platforms...
3.1 and
automatic parallelizationAutomatic parallelization, also auto parallelization, autoparallelization, or parallelization, the last one of which implies automation when used in context, refers to converting sequential code into multi-threaded or vectorized code in order to utilize multiple processors simultaneously in a...
for
symmetric multiprocessingIn computing, symmetric multiprocessing involves a multiprocessor computer hardware architecture where two or more identical processors are connected to a single shared main memory and are controlled by a single OS instance. Most common multiprocessor systems today use an SMP architecture...
. With the add-on capability
Cluster OpenMP, the compiler can also automatically generate
Message Passing InterfaceMessage Passing Interface is a standardized and portable message-passing system designed by a group of researchers from academia and industry to function on a wide variety of parallel computers...
calls for
distributed memoryIn computer science, distributed memory refers to a multiple-processor computer system in which each processor has its own private memory. Computational tasks can only operate on local data, and if remote data is required, the computational task must communicate with one or more remote processors...
multiprocessingMultiprocessing is the use of two or more central processing units within a single computer system. The term also refers to the ability of a system to support more than one processor and/or the ability to allocate tasks between them...
from OpenMP directives.
Intel C++ Compiler belongs to the family of compilers with the
Edison Design GroupThe Edison Design Group is a company that makes compiler frontends . Their frontends are widely used in commercially available compilers and code analysis tools. Users include the Intel C++ compiler, SGI MIPSpro, The Portland Group, and Comeau C++...
frontend (like the
SGISilicon Graphics, Inc. was a manufacturer of high-performance computing solutions, including computer hardware and software, founded in 1981 by Jim Clark...
MIPSproOpen64 is an open source, optimizing compiler for the Itanium and x86-64 microprocessor architectures. It derives from the SGI compilers for the MIPS R10000 processor, called MIPSPro. It was initially released in 2000 as GNU GPL software under the name Pro64. The following year, University of...
, Comeau C++, Portland Group, and others). The compiler is also notable for being widely used for
SPEC CPUThe Standard Performance Evaluation Corporation is a non-profit organization that aims to "produce, establish, maintain and endorse a standardized set" of performance benchmarks for computers....
Benchmarks of
IA-32IA-32 , also known as x86-32, i386 or x86, is the CISC instruction-set architecture of Intel's most commercially successful microprocessors, and was first implemented in the Intel 80386 as a 32-bit extension of x86 architecture...
,
x86-64x86-64 is an extension of the x86 instruction set. It supports vastly larger virtual and physical address spaces than are possible on x86, thereby allowing programmers to conveniently work with much larger data sets. x86-64 also provides 64-bit general purpose registers and numerous other...
, and Itanium 2 architectures.
The Intel C++ Compiler is available in various packages from Intel including
Intel Parallel StudioIntel Parallel Studio is a software development product developed by Intel that plugs into the Microsoft Visual Studio Integrated Development Environment. Its purpose is to facilitate developing programs for parallel computing...
, Intel Parallel Studio XE, the Intel C++ Composer package, the Intel C++ Composer XE package, the Intel Composer XE package and the Intel Cluster Studio. The
Intel Software Products site provides more information.
Optimizations
Intel tunes its compilers to optimize for its hardware platforms to minimize stalls and to produce code that executes in the fewest number of cycles. The Intel C++ Compiler supports three separate high-level techniques for optimizing the compiled program:
interprocedural optimizationInterprocedural optimization is a collection of compiler techniques used in computer programming to improve performance in programs containing many frequently used functions of small or medium length...
(IPO),
profile-guided optimizationProfile-guided optimization is a compiler optimization technique in computer programming to improve program runtime performance. In contrast to traditional optimization techniques that solely use the source code, PGO uses the results of test runs of the instrumented program to optimize the final...
(PGO), and high-level optimizations (HLO). It also supports tools and techniques for adding and maintaining parallelism to applications.
Profile-guided optimization refers to a mode of optimization where the compiler is able to access data from a sample run of the program across a representative input set. The data would indicate which areas of the program are executed more frequently, and which areas are executed less frequently. All optimizations benefit from profile-guided feedback because they are less reliant on heuristics when making compilation decisions.
High-level optimizations are optimizations performed on a version of the program that more closely represents the source code. This includes
loop interchangeIn compiler theory, loop interchange is the process of exchanging the order of two iteration variables.For example, in the code fragment: for i from 0 to 10 for j from 0 to 20 a[i,j] = i + jloop interchange would result in: for j from 0 to 20...
,
loop fusionLoop fusion, also called loop jamming, is a compiler optimization, a loop transformation, which replaces multiple loops with a single one.- Example in C : int i, a[100], b[100]; for Loop fusion, also called loop jamming, is a compiler optimization, a loop transformation, which replaces multiple...
, loop unrolling, loop distribution, data prefetch, and more. These optimizations are usually very aggressive and may take considerable compilation time.
Interprocedural optimization applies typical compiler optimizations (such as constant propagation) but using a broader scope that may include multiple procedures, multiple files, or the entire program.
The compilers include a parallel debugger extension, Intel Threading Building Blocks, lambda function support, and a source checker tool for use with threaded code.
Intel's compiler has been criticized for applying, by default, floating-point optimizations not allowed by the C standard and that require special flags with other compilers such as
gccThe GNU Compiler Collection is a compiler system produced by the GNU Project supporting various programming languages. GCC is a key component of the GNU toolchain...
.
Languages
Intel's suite of compilers has front ends for
CC is a general-purpose computer programming language developed between 1969 and 1973 by Dennis Ritchie at the Bell Telephone Laboratories for use with the Unix operating system....
,
C++C++ is a statically typed, free-form, multi-paradigm, compiled, general-purpose programming language. It is regarded as an intermediate-level language, as it comprises a combination of both high-level and low-level language features. It was developed by Bjarne Stroustrup starting in 1979 at Bell...
, and
FortranFortran is a general-purpose, procedural, imperative programming language that is especially suited to numeric computation and scientific computing...
.
Early versions of ICC for Linux that predate
GCCThe GNU Compiler Collection is a compiler system produced by the GNU Project supporting various programming languages. GCC is a key component of the GNU toolchain...
3.x use the
DinkumwareDinkumware is a software company specializing in core libraries for C/.The company has provided the standard library implementation that ships with Microsoft since 1996, and claims to be the leading supplier of and libraries to the embedded community.They also provide libraries for Java and...
name manglingIn compiler construction, name mangling is a technique used to solve various problems caused by the need to resolve unique names for programming entities in many modern programming languages....
scheme in order to provide a more standard implementation of C++ than GCC 2.x. This made its
ABIIn computer software, an application binary interface describes the low-level interface between an application program and the operating system or another application.- Description :...
incompatible with both GCC versions. Intel removed the Dinkumware libraries in the 10.0 release (June 2007). Since then, the compiler has been and remains compatible with GCC 3.2 and later.
Versions
The following versions of Intel C++ Compiler have been released:
| Compiler version |
Release date |
Major New Features |
| Intel C++ Composer XE 2011 Update 6 and above (compiler 12.1) |
September 8, 2011 |
Intel Cilk Plus Cilk Plus is an extension to the C and C++ programming languages, designed for multithreaded parallel computing.On July 31, 2009, Cilk Arts, producers of the Cilk++ programming language, announced that its products and engineering team were now part of Intel Corp...
language extensions updated to support specification version 1.1 and available on Mac OS X in addition to Windows and Linux, Intel Threading Building BlocksIntel Threading Building Blocks is a C++ template library developed by Intel Corporation for writing software programs that take advantage of multi-core processors...
updated to support version 4.0, Apple blocks supported on Mac OS X, improved C++11 support including support for Variadic templates, OpenMPOpenMP is an API that supports multi-platform shared memory multiprocessing programming in C, C++, and Fortran, on most processor architectures and operating systems, including Linux, Unix, AIX, Solaris, Mac OS X, and Microsoft Windows platforms...
3.1 support. |
| Intel C++ Composer XE 2011 up to Update 5 (compiler 12.0) |
Nov 7, 2010 |
Intel Cilk Plus Cilk Plus is an extension to the C and C++ programming languages, designed for multithreaded parallel computing.On July 31, 2009, Cilk Arts, producers of the Cilk++ programming language, announced that its products and engineering team were now part of Intel Corp...
language extensions, Guided Auto-Parallelism, Improved C++0xC++11, also formerly known as C++0x, is the name of the most recent iteration of the C++ programming language, replacing C++03, approved by the ISO as of 12 August 2011...
support. |
| Intel C++ Compiler 11.1 |
June 23, 2009 |
Support for latest Intel SSE SSE4.2, AVX Advanced Vector Extensions is an extension to the x86 instruction set architecture for microprocessors from Intel and AMD proposed by Intel in March 2008 and first supported by Intel with the Westmere processor shipping in Q1 2011 and now by AMD with the Bulldozer processor shipping in Q3 2011.AVX...
and AESAdvanced Encryption Standard Instruction Set is an extension to the x86 instruction set architecture for microprocessors from Intel and AMD proposed by Intel in March 2008...
instructions. Parallel Debugger Extension. Improved integration into Microsoft Visual Studio, Eclipse CDT 5.0 and Mac Xcode IDE. |
| Intel C++ Compiler 11.0 |
November 2008 |
Initial C++0x C++11, also formerly known as C++0x, is the name of the most recent iteration of the C++ programming language, replacing C++03, approved by the ISO as of 12 August 2011...
support http://www.intel.com/software/products/compilers/docs/clin/main_cls/copts/ccpp_options/option_std.htm. VS2008 IDE integration on Windows. OpenMP 3.0. Source Checker for static memory/parallel diagnostics. |
| Intel C++ Compiler 10.1 |
November 7, 2007 |
New OpenMP* compatibility runtime library: if you use the new OpenMP RTL, you can mix and match with libraries and objects built by Visual C++. To use the new libraries, you need to use the new option "-Qopenmp /Qopenmp-lib:compat" on Windows, and "-openmp -openmp-lib:compat" on Linux. This version of the Intel compiler supports more intrinsics from Visual Studio 2005.
VS2008 support - command line only in this release. The IDE integration was not supported yet. |
| Intel C++ Compiler 10.0 |
June 5, 2007 |
Improved parallelizer and vectorizer, Streaming SIMD Extensions 4 (SSE4 SSE4 is a CPU instruction set used in the Intel Core microarchitecture and AMD K10 . It was announced on 27 September 2006 at the Fall 2006 Intel Developer Forum, with vague details in a white paper; more precise details of 47 instructions became available at the Spring 2007 Intel Developer Forum...
), new and enhanced optimization reports for advanced loop transformations, new optimized exception handling implementation. |
| Intel C++ Compiler 9.0 |
June 14, 2005 |
AMD64 architecture (for Windows), software-based speculative pre-computation (SSP) optimization, improved loop optimization reports. |
| Intel C++ Compiler 8.1 |
September, 2004 |
AMD64 architecture (for Linux). |
| Intel C++ Compiler 8.0 |
December 15, 2003 |
Precompiled headers, code-coverage tools. [ftp://download.intel.com/support/performancetools/c/linux/v8/c8lin_relnotes.pdf] |
| Intel C++ Compiler 7.1 |
March, 2003 |
Partial support for the Intel Pentium 4Pentium 4 was a line of single-core desktop and laptop central processing units , introduced by Intel on November 20, 2000 and shipped through August 8, 2008. They had a 7th-generation x86 microarchitecture, called NetBurst, which was the company's first all-new design since the introduction of the...
with Streaming SIMD Extensions 3 (SSE3SSE3, Streaming SIMD Extensions 3, also known by its Intel code name Prescott New Instructions , is the third iteration of the SSE instruction set for the IA-32 architecture. Intel introduced SSE3 in early 2004 with the Prescott revision of their Pentium 4 CPU...
). [ftp://download.intel.com/support/performancetools/c/linux/v7/c71Lin_relnotes.pdf] |
| Intel C++ Compiler 7.0 |
November 25, 2002 |
[ftp://download.intel.com/support/performancetools/c/linux/v7/c71Lin_relnotes.pdf] |
| Intel C++ Compiler 6.0 |
April 24, 2002 |
[ftp://download.intel.com/support/performancetools/c/linux/v6/c_ug_lnx60.pdf] |
Experimental/prototype versions
In addition, the following "prototype" editions have been made available:
| Compiler version |
Release date |
Major New Features |
| Intel STM Compiler Prototype Edition |
September 17, 2007 |
Prototype version of the Intel compiler that implements support for Software Transactional Memory In computer science, software transactional memory is a concurrency control mechanism analogous to database transactions for controlling access to shared memory in concurrent computing. It is an alternative to lock-based synchronization. A transaction in this context is a piece of code that...
(STM). The Intel STM Compiler supports Linux and Windows, producing 32 bit code for x86 (Intel and AMD) processors. Intel stated the belief that "The availability of such a prototype compiler allows unprecedented exploration by C / C++ software developers of a promising technique to make programming for multi-core easier." The STM compiler requires that you already have the Intel compiler installed. |
| Intel Concurrent Collections for C/C++ 0.3 |
September, 2008 |
Intel Concurrent Collections for C/C++ provides a mechanism for constructing C++ programs that execute in parallel. It allows developers to ignore issues of parallelism such as low-level threading constructs or scheduling/distribution of computations. The model allows developers to specify high-level computational steps including inputs and outputs without imposing unnecessary ordering on their execution. Code within the computational steps is written using standard serial constructs of the C++ language. Data is either local to a computational step or it is explicitly produced and consumed by them. It supports multiple styles of parallelism (e.g., data, task, pipeline parallel). |
Flags and manuals
Documentation can be found at the
Intel Software Technical Documentation site.
| Windows |
Linux & MacOSX |
Comment |
| /Od |
-O0 |
No optimization |
| /O1 |
-O1 |
Optimize for size |
| /O2 |
-O2 |
Optimize for speed and enable some optimization |
| /O3 |
-O3 |
Enable all optimizations as O2, and intensive loop optimizations |
| /QxO |
-xO |
Enables SSE3, SSE2 and SSE instruction sets optimizations for non-Intel CPUs |
| /fast |
-fast |
Shorthand. On WindowsMicrosoft Windows is a series of operating systems produced by Microsoft.Microsoft introduced an operating environment named Windows on November 20, 1985 as an add-on to MS-DOS in response to the growing interest in graphical user interfaces . Microsoft Windows came to dominate the world's personal...
this equates to "/O3 /Qipo /QxHost /no-prec-div" ; on LinuxLinux is a Unix-like computer operating system assembled under the model of free and open source software development and distribution. The defining component of any Linux system is the Linux kernel, an operating system kernel first released October 5, 1991 by Linus Torvalds...
"-O3 -ipo -static -xHOST -no-prec-div". Note that the processor specific optimization flag (-xHOST) will optimize for the processor compiled on—it is the only flag of -fast, which may be overridden. |
| /Qprof-gen |
-prof_gen |
Compile the program and instrument it for a profile generating run. |
| /Qprof-use |
-prof_use |
May only be used after running a program that was previously compiled using prof_gen. Uses profile information during each step of the compilation process. |
Debugging
The Intel compiler provides debugging information that is standard for the common debuggers (
DWARF 2DWARF is a widely used, standardized debugging data format. DWARF was originally designed along with Executable and Linkable Format , although it is independent of object file formats...
on Linux, similar to gdb, and
COFFThe Common Object File Format is a specification of a format for executable, object code, and shared library computer files used on Unix systems...
for Windows). The flags to compile with debugging information are
/Zi on Windows and
-g on Linux.
Intel also provides its own
debuggerA debugger or debugging tool is a computer program that is used to test and debug other programs . The code to be examined might alternatively be running on an instruction set simulator , a technique that allows great power in its ability to halt when specific conditions are encountered but which...
called
idb, which can be run in both dbx and
gdbThe GNU Debugger, usually called just GDB and named gdb as an executable file, is the standard debugger for the GNU software system. It is a portable debugger that runs on many Unix-like systems and works for many programming languages, including Ada, C, C++, Objective-C, Free Pascal, Fortran, Java...
compatible command mode.
While the Intel compiler can generate a gprof compatible profiling output, Intel also provides a kernel level, system-wide statistical profiler as a separate product called
VTuneIntel VTune Amplifier XE is a commercial application for software performance analysis for 32 and 64-bit x86 based machines, and has both GUI and command line interfaces. It is available for both Linux and Microsoft Windows operating systems...
. VTune features an easy-to-use GUI (integrated into Visual Studio for Windows,
EclipseEclipse is a multi-language software development environment comprising an integrated development environment and an extensible plug-in system...
for Linux) as well as a command line interface.
The 11.x releases of the compiler introduced the Parallel Debugger Extension, which provides techniques for debugging threaded applications. It can be used with other, compatible compilers, such as Microsoft Visual C++ on Windows as available in Visual Studio 2005 and 2008 and gcc on Linux. Visual Studio 2010 support was added by the 12.x releases.
Criticism
Intel and third parties have published benchmark results to substantiate performance leadership claims over other commercial, open source and AMD compilers and libraries on Intel and non-Intel processors. Intel and AMD have documented flags to use on the Intel compilers to get optimal performance on Intel and AMD processors. Nevertheless, the Intel compilers have been accused of producing sub-optimal code with mercenary intent. One developer, in 2009, wrote:
This vendor-specific CPU dispatching decreases the performance on non-Intel processors of software built with an Intel compiler or an Intel function library - possibly without the knowledge of the programmer. This has allegedly led to misleading
benchmarksIn computing, a benchmark is the act of running a computer program, a set of programs, or other operations, in order to assess the relative performance of an object, normally by running a number of standard tests and trials against it...
. A legal battle between AMD and Intel over this and other issues has been settled in November 2009. In late 2010, AMD settled an
US Federal Trade CommissionThe Federal Trade Commission is an independent agency of the United States government, established in 1914 by the Federal Trade Commission Act...
antitrust investigationCompetition law, known in the United States as antitrust law, is law that promotes or maintains market competition by regulating anti-competitive conduct by companies....
against Intel.
The FTC settlement included a disclosure provision where Intel must::
See also
- Intel Software Network
The Intel Software Network is an international online program designed by Intel to encourage and support independent software vendors in developing applications for Intel hardware and software products...
(support and discussion)
- Intel Fortran Compiler
Intel Fortran Compiler, also known as IFORT, is a Fortran compiler developed by Intel. It generates code for IA-32, Intel 64 processors. Compilers are available for Linux, Microsoft Windows and Mac OS X. On Windows, it is known as Intel Visual Fortran...
- Intel Math Kernel Library
Intel's Math Kernel Library is a library of optimized, math routines for science, engineering, and financial applications. Core math functions include BLAS, LAPACK, ScaLAPACK, Sparse Solvers, Fast Fourier Transforms and Vector Math....
- Intel Integrated Performance Primitives Library
Intel Integrated Performance Primitives is a multi-threaded software library of functions for multimedia and data processing applications, produced by Intel....
External links