Does the Intel C++ Compiler plug-in integrate into Microsoft Developer Studio 5.0?

How can I obtain the Intel® Compilers for Win32 systems?
The Intel C/C++ and FORTRAN Compiler plug-ins are available only as part of the VTune 2.4 CD. For details on ordering, check the website: http://developer.intel.com/design/perftool/

Where can I find the Intel C/C++ Compiler release notes?
The release notes can be found in c:/perform/doc/iccnotes.wri.

Where can I find the Intel FORTRAN Compiler release notes?
The release notes can be found in c:/perform/doc/ifcnotes.wri.

Where can I find the Intel C/C++ and FORTRAN Compiler User's Guides?
There are two user's guides. One is provided with the C/C++ Compiler and one is provided with the FORTRAN Compiler. These manuals are provided only in electronic form in the Adobe Acrobat 3.0 format. No hard copies are available.

Where can I find more information about VTune, the Compilers, and other performance software for Intel?
Our development tools web site is located at http://developer.intel.com/design/develop.htm. Information on Intel’s latest development tools, including VTune and the Intel Compilers is provided at this site.

Where can I read more about optimizing my code running on the Intel Architecture?
There is an extensive set of documents and tutorials provided detailing the Intel Architecture . These include the:

• Intel Architecture Optimization Guide
• Pentium^®, Pentium Pro and Pentium II processor Manuals (3 volumes for each)
• MMX^TM Technology manuals
• On-Line tutorials on optimization and processor architectures

These are available on the VTune CD and on the Intel Developer Insight web site. Go to the web site: http://developer.intel.com/design/develop.htm and select the Intel Architecture Tutorials link. A hard copy of the Intel Architecture Optimization Guide can be obtained by calling 1-800-548-4725 and requesting document number 242816-00x.

I have both Microsoft Visual C++ 4.2 and Microsoft Visual C++ 5.0 installed on my system. Must I uninstall and reinstall the Intel compiler each time I switch between 4.2 and 5.0, or is it only necessary that I change my environment variables: path, lib, and include?
For IDE use, you must uninstall the Intel C/C++ Compiler version 2.4 and reinstall it into the desired IDE.

Does the Intel FORTRAN Compiler plug-in require the Microsoft's Visual C++ product be installed?
Yes. The Intel Compiler plug-in requires that Microsoft Visual C++ be installed because it uses the Microsoft Visual C++ linker and runtime libraries (i.e. libc.lib).

Are the Microsoft Visual C++ linker and runtime libraries required for the Intel FORTRAN Compiler plug-in or is there an alternative source?
We know of no other source for a replacement linker or runtime libraries.

What is the proper way to uninstall an existing Intel Compiler plug-in on my system?
To uninstall an existing Intel Compiler plug-in, select Start -> Setting -> Control Panel -> Add/Remove Application. Select Intel Compiler plug-in and click Add/Remove button. Or, from Start -> Intel Performance Tool Set -> Uninstall Intel C++ Compiler plug-in.

When I installed Intel C/C++ Compiler then Microsoft Visual C++, why isn’t the Intel C/C++ Compiler integrated into the Visual C++ development environment?
You must first have Microsoft Visual C++ on your system when you install the Intel C/C++ Compiler. The Intel C/C++ Compiler installation procedure automatically integrates the Intel C/C++ Compiler add-on with the Visual C++ development environment. This gives you the choice of using the Intel C/C++ Compiler to compile the performance-critical portions of the projects that you create in Visual C++.

I installed the Intel C/C++ Compiler. How do I invoke it from within the Visual C++ development environment?
To invoke the Intel C/C++ Compiler from within the Visual C++ development environment, follow these steps:

1. Open a Microsoft project (.mdp or .mak) file in Visual C++.
2. Click on the Tools menu in the Developer Studio.
3. Click Select Compiler. The Select Compiler window opens.
4. Click on the Intel C/C++ Compiler option.
5. Click OK.

Is it possible to have the Intel Compiler active in both Microsoft Visual C++ 4.x and Microsoft Visual C++ 5.0 in the same system?
No. Only one of the Intel C/C++ or FORTRAN Compilers can be active in a single version of MSVC at any time. To switch between versions of MSVC, it is necessary to uninstall the Intel Compiler (not simply deleting it) then re-install it selecting the different version of MSVC on the Select Microsoft Compiler screen during Intel Compiler installation.

Can I upgrade versions of Microsoft Visual C++ and still use the Intel Compiler I had previously installed? When I uninstalled Microsoft Visual C++ 4.x and installed Microsoft Visual C++ 5.0, I get the following error message when I try to install a new version of the Intel Compiler: "This selection tool was already installed in a different version of VC++. Please install in same".
No. To solve this problem, uninstall the Intel Compiler and re-install it into the new version of Microsoft Visual C++ , making your selection on the Select Microsoft Compiler screen during Intel Compiler installation.

I am having trouble installing the Intel Compiler. After the initial status bar shows "installing", it just terminates.
The problem could be caused by:

1. Insufficient disk space for extracting the installation files into a temporary directory. About 30 MBytes of disk space is required to install although the compiler will finally consume only about 10 MBytes.
   

2. The absence of a TEMP environment variable. Make sure that a TEMP environment variable is specified.

How do I enable full optimization?
The Intel Compilers by default enable full optimization. The -O2 option is the default optimization option.

Can I use VTune to optimize code that is compiled by the Intel C/C++ Compiler?
A. Yes. Use the same Compiler options as recommended by VTune for Microsoft Visual C++ 4.x/5.0.

I have some 3D graphics code that requires converting floating point values to integer values. How can I improve the performance?

In C programs, floating point to integer conversions are normally somewhat slow. The C language requires truncation of floating point values assigned to integers. However, for normal floating point calculations, the processor's default rounding mode of "round to nearest" is used. Thus, C Compilers must add code to adjust the processor rounding mode before and after the floating point to integer conversion.

To improve the performance of floating point to integer conversions, the Intel C/C++ Compiler offers the -Qrcd option. This option prevents the Compiler from generating the code which adjusts the processor rounding mode before and after conversions. This reduces the overhead of the conversion significantly, but can lead to slightly different results because the "round to nearest" processor rounding mode is used.

Note: The -Qrcd option and other optimization options are described in detail in the "Optimizations" chapter of the Intel C/C++ Compiler User's Guide.

How do I produce code that targets a particular processor ?
To target a binary application to run on a specific processor, use the -G option to optimize for that processor:

-GB	Choose GB when the binary application must run well on a variety of Intel processors. This type blends optimization for performance across the entire Intel family of processors. The GB option is ON by default.
-G5	Choose G5 when the binary application runs primarily on the Pentium® processor.
-G6	Choose G6 when the binary application runs primarily on the Pentium® Pro processors, Pentium II processors or Celeron™ processors

Note: The -G target processor options and other optimization options are described in detail in the "Optimizations" chapter of the Intel C/C++ Compiler User's Guide for Win32* Systems. Regardless of your choice, your code will still run on all 32-bit Intel processors (Intel486™ processor, Pentium® processor, Pentium Pro processor, Pentium II processor, Celeron™ processor), these options only guide the compiler towards the processor on which your application will be primarily executed.

Why does -Qmem slow my code down?
Low iteration count loops that are common in integer code (character manipulation, byte manipulation, graphics) can be hurt by the overhead of various loop transformations, like loop unrolling. In these cases, the overhead of calculating the loop constraints and addressing may be greater than that of loop.

Also, some transformations increase the size of the code which may degrade performance if the application is sensitive to such.

When I am using the profile-guided optimizations available with the Intel Compiler, the –Qprof_use switch does not generate a *.dpi file. What am I doing wrong?
In order to generate the pgopti.dpi file, the Intel C/C++ Compiler must read the dynamic information files (*.dyn) generated by the instrumented program. Use the -Qprof_dir option to specify the directory in which dynamic information files will be located. The -Qprof_dir option should be used for both the instrumentation compilation (-Qprof_gen) and the feedback compilation (-Qprof_use) phases of profile-guided optimization.

Note: Please refer to the "Optimizations" chapter of the Intel C/C++ Compiler User's Guide for more information on profile-guided optimizations.

My code contains #pragma intrinsic(memcpy), but the Intel C/C++ Compiler generates a call to memcpy rather than inline code. Why?
The pragma intrinsic is accepted without error but has no effect. Your command line argument must include the –Oi (or -O2) option in order to inline intrinsic functions.

Is there any on-line help for the Intel C/C++ and FORTRAN compiler plug-ins?
Command-line help is available by typing the following at the command line: "icl -help" or "icl -?" for the Intel C/C++ compiler, and "ifl -help" or "ifl -?" for the Intel FORTRAN compiler. Additional on-line help can be found in the Intel C/C++ Compiler User's Manual for Win32* Systems.

How do I know which Intel compiler switches/options I am using in the Microsoft Visual C++* Integrated Development Environment(IDE)?
The Intel compiler switches/options can be found in the 'Project Options' section of the 'C/C++' tab in the 'Project Settings' dialog box. To get to the 'Project Settings' dialog box select the 'Project' menu item followed by the 'Settings' submenu item. Additional options you want to include in each compilation can be specified in the icl.cfg file located in the perform/bin directory.

Is there a version of the Intel compiler which runs under the Linux* operating system?
There is no version of the Intel compiler that runs under the Linux operating system.

Where can I get a copy of the Intel(R) FORTRAN Compiler for Unix?

The Intel® FORTRAN Compiler for Unix is no longer available. You might consider EPC's FORTRAN Compiler for UNIX systems.

Using the Microsoft Visual C++ IDE, I have inserted several files into my project. How do I use the Microsoft Visual C++ compiler to compile selected files, when I have selected the Intel compiler to be used by default.
The Intel C/C++ Compiler plug-in provides support to override the compiler selected in the Intel Compiler Selection Tool. Using this feature allows one to force the use of either the Intel C/C++ Compiler or the Microsoft Visual C++ Compiler for selected files, while building most of the files in a project using the compiler that was selected in the Intel Compiler Selection Tool.

The feature is activated using special preprocessor macros:

_USE_INTEL_COMPILER use Intel C/C++ compiler for selected files

_USE_NON_INTEL_COMPILER use Microsoft Visual C/C++ compiler for selected files

Adding one of these macros to the build settings for a file will override the currently selected compiler and force compilation with the specified compiler. To use these macros in the Microsoft Developer Studio, follow these steps:

1. Open a C/C++ project.
2. Open the "Project Settings" dialog box.
3. In the "Project Settings" dialog, select the configuration to effect in the "Settings For" list.
4. Select the file(s) you wish to modify.
5. Click on the C/C++ tab.
6. In the C/C++ tab, select General from the Category drop-down list.
7. In the "Preprocessor definitions" edit box, add the _USE_INTEL_COMPILER macro to force the use of the Intel C/C++ Compiler for the selected file(s). Add the _USE_NON_INTEL_COMPILER macro to force the use of the Microsoft Visual C++ Compiler for the selected files.

Please see the Intel C/C++ Compiler Release Notes for more information.

My program compiles cleanly with Microsoft Visual C++, but when I use the Intel Compiler I get many more warnings. Why?

1. At its default settings, the Intel Compiler warns about certain constructs that the Microsoft compiler does not. The -w or -Wn option is used to suppress warning messages or to enable remarks during the preprocessing and compilation phases. The available options are:

Please see the Intel C/C++ Compiler User's Guide for Win32* Systems for more information

Does the C/C++ compiler support 64-bit ints and 80-bit floats?
64-bit ints are supported with the __int64 or long long datatypes. The compiler does support 80-bit long doubles when the /Qlong_double option is specified. See the Intel C/C++ Compiler User's Guide for Win32* Systems for limitation on this option.

When do I need to use the xilink.exe instead of link.exe?
The executable xilink.exe is used when with multifile interprocedural optimization (-Qipo). Multifile interprocedural optimization (-Qipo) involves an additional compilation step immediately before the link step. This step is hidden when you compile and link using icl. However, most applications are built using a makefile or a file with a similar function to a makefile. Makefiles usually call the Microsoft linker link.exe to do the linking. However, when you use the -Qipo option to accomplish multifile interprocedural optimization you must use the Intel linker driver xilink.exe instead. The following example demonstrates usage for xilink.exe:

Please see the Intel C/C++ Compiler User's Guide for Win32* Systems for more information.

Can I mix object files from Microsoft, Borland, Symantec, Lahey, Metaware, etc., compilers with the Intel C/C++ Compiler?
The Intel C/C++ Compiler is only Microsoft compatible.

Where can I find a list of known bugs and possible workarounds in the compiler?
A file containing a list of known problems and their potential workaround is placed in your /perform/doc directory during installation. If any additional bugs are discovered, please contact us at developer_support@intel.com or http://developer.intel.com/design/perftool/icl24/icl24sup.htm.

What are icl.cfg / ifl.cfg configuration files?
A user configuration file named icl.cfg/ifl.cfg can be added to the directory where icl/ifl is installed. In this file, you can specify common options that you want to be included in each compilation. Options in the configuration file are processed in the order they appear, followed by any command-line options specified on Compiler invocation.

You can decrease the time you spend entering command-line options and ensure consistency by using the configuration file to automate some command-line entries. However, you should be aware that options placed in the configuration file will be included each time you run the Compiler. See the Intel C/C++ Compiler User’s Guide for more details.

Click here to view a sample icl.cfg file.

Why do I have to prototype floating point routines?
A. Due to the nature of the floating point units register stack, it is critical that care is taken to ensure functions that return floats and double are prototyped as such. When not done, the Compiler assumes the return type is an int, and will not be able to manage the floating point stack correctly. In some cases, this can end up causing an application to not execute correctly, giving wrong results, or causing floating point stack overflow.

What are the differences between the various Intel Compiler debug switches?
A. In the Intel C/C++ Compiler, the -Zi and -Z7 options are equivalent. Both options instruct the Compiler to generate symbolic debugging information in the object file for use by source-level debuggers. The -Zd option only produces line number information in the object file (for debugging).

What are the default Intel C/C++ and FORTRAN Compilers’ calling conventions?
The Intel C/C++ Compiler supports the same calling conventions as Microsoft Visual C++. These are __cdecl, __stdcall, __fastcall, and thiscall. The __cdecl calling convention is the default. The differences between them are in the naming of the routines, the stack usage, and parameter passing. (Please refer to the Microsoft Visual C++ Books Online for details on the differences.)

The Intel FORTRAN Compiler supports two calling conventions, a hybrid __cdecl/UNIX ABI convention and the Microsoft PowerStation FORTRAN default calling convention.

• The hybrid __cdecl/UNIX ABI is compatible with the Microsoft PowerStation FORTRAN "C" calling convention. That is, if the programmer includes an interface block in the FORTRAN code compiled by PowerStation and defines the calling convention to be 'C', the interface will match the Intel FORTRAN default. There are more details about the calling conventions in the Intel Compiler User's Guides.
• Using the Intel FORTRAN option /Gz, the interface generated will exactly match the default call interface generated by PowerStation by default (i.e., without any interface block).

Can I compile my application with a mix of the Intel Compiler and the Microsoft Visual C++* Compiler?
Yes, the Intel C/C++ Compiler allows this through use of the _USE_INTEL_COMPILER and _USE_NON_INTEL_COMPILER macros. These macros are documented in the release notes.

Can I use the Intel Compilers from a DOS command-line?
While the Intel Compilers can be invoked from a DOS command-line outside of the Microsoft Visual C++ Integrated Development Environment (IDE), Intel does not produce its own linker, header files, C/C++ libraries or IDE so the Intel compiler plug-ins still require those components from the Microsoft Visual C++ to produce executable programs. With the Microsoft Visual C++ product installed, the Intel Compilers can be invoked either from the DOS command line or from within the IDE.

How can I use the Intel FORTRAN compiler with Microsoft Developer Studio 97 and Visual C++ 5.0?

Setup the Directories for Executables, Libraries, and Include Files Check that the correct environment variables have been set to run the Intel FORTRAN Compiler. This step is particularly important if the Intel C/C++ Compiler plug-in is not already installed in Developer Studio 97 (Visual C++ 5.0).

1. Select Options from the Tools menu item.

2. Select the Directories tab.

3. Under the "Show directories for:" dropdown menu, the following menu items should include the directories shown (assuming you have installed the Intel FORTRAN Compiler on your C: drive). You must add the directory entries if they don't exist.
   

You are now ready to create and build a FORTRAN Project:

Creating and Building a FORTRAN Project