Intel® Fortran Compiler 10.1 for Linux*
Release Notes

Contents

Overview

This product provides tools for Linux* software developers to create Fortran applications that deliver outstanding performance. Intel® Fortran Compiler is a full-language Fortran 95 compiler with many features from the Fortran 2003 standard, plus a wide range of popular language extensions. Intel compilers support multi-threaded code development through autoparallelism and OpenMP* support.

Product Contents

This product is available in two editions.

The Standard Edition contains the following components:

The Professional Edition includes all of the Standard Edition and adds the Intel® Math Kernel Library, which contains highly optimized, extensively threaded, mathematical functions for engineering, scientific, and financial applications that require maximum performance..

Note: The installation path for the Intel® Fortran Compiler is /opt/intel/fc/10.1.xxx , where xxx represents a 3-digit update number. The term <install-dir> is used in throughout this document to refer to the default installation path.

Installation of the Intel® Math Kernel Library is separate from that of the compiler. Please see the Intel® Math Kernel Library Installation Guide for details.

To receive technical support and product updates for the tools provided in this product you need to register. For how to register, please see Technical Support section below.

Compatibility

You must recompile all Fortran sources that were compiled with compilers earlier than version 8.0, including those that create .mod files. Third-party libraries built with versions earlier than 8.0 will also need to be rebuilt - if you are using third-party libraries that do not support Intel Fortran, please let us know which ones through Intel® Premier Support at https://premier.intel.com. Fortran sources built with Intel Fortran 8.0 or later do not need to be recompiled for use with version 10.1.

What's New in Versions 10.0 and 10.1

The following section discusses new features and changes in the Intel Fortran Compiler since version 10.0. Version numbers may not represent a released update - the indicated and later versions have these changes. Please see the separate release notes for the Intel Debugger.

Change History

10.1.022
Corrections to reported problems only
10.1.021
Corrections to reported problems only
10.1.019
Corrections to reported problems only
10.1.018
-no-prof-gen and -no-prof-use documented
-prof-gen-sampling and -ssp will be removed in a future release
-prof-hotness-threshold added
10.1.017
Corrections to reported problems only
10.1.015
Corrections to reported problems only
10.1.014
Information added about future behavior changes
10.1.013
-[no-]opt-prefetch-excl-hint added
-opt-malloc-options
now supported on IA-64 architecture
Information about future deprecation of legacy OpenMP libraries added
10.1.012
Name decoration again applied to BIND(C) objects
10.1.011
-mia32 added
-opt-jump-tables added
-[no-]opt-loadpair added
-opt-malloc-options=4 value added
-[no-]opt-mod-versioning added
-[no-]opt-prefetch-initial-values added
-[no-]opt-prefetch-next-iteration added
-[no-]unroll-aggressive now available on IA-64 architecture
10.1.008
First release of 10.1

New and Changed Command Line Options

The following is a listing of command line options that are new or have changed since the initial version 9.1 release. Please refer to the compiler documentation for more information on these options.

-assume [no]old_boz
Controls how binary, octal and hexadecimal constants are treated as arguments to the INT, REAL, DBLE and CMPLX intrinsics. See note on Fortran 2003 Behaviors below. (Default: -assume noold_boz)
-assume [no]old_unit_star
Controls how input and output to unit *, as well as ACCEPT, PRINT and TYPE is handled.. See note on Fortran 2003 Behaviors below. (Default: -assume old_unit_star)
-assume protect_parens
Determines whether the optimizer honors parentheses in REAL and COMPLEX expression evaluations by not reassociating operations. (Default: off)
-assume [no]realloc_lhs
Determines whether allocatable objects on the left hand side of an assignment are treated according to Fortran 95/90 rules or Fortran 2003 rules. See note on Fortran 2003 Behaviors below. (Default: off)
-assume [no]std_mod_proc_name
Determines whether the names of module procedures are allowed to conflict with user external symbol names. See note below. (Default: off)
-axS
Specifies that the compiler is to generate SSE4 Vectorizing Compiler and Media Accelerators instructions for future Intel processors that support the instructions, as well as generic IA-32 architecture code. (IA-32 and Intel® 64 architecture only, default: off)
-check [no]pointer
Enables or disables run-time checking for accesses through null pointers or of unallocated ALLOCATABLE variables. (Default: off)
-cxxlib-nostd
Prevents the compiler from linking with the standard C++ library (Default: off)
-diag-<type> <diag-list>
Controls the display of diagnostic information (Default: off)
-diag-dump
Tells the compiler to print all enabled diagnostic messages and stop compilation (Default: off)
-diag-enable sv[1|2|3]
Enables the Static Verifier. (Default: off)
-diag-enable sv-include
Specifies that include files should also be considered by the Static Verifier
-diag-file[=file]
Causes the results of diagnostic analysis to be output to a file. (Default: off)
-diag-file-append[=file]
Causes the results of diagnostic analysis to be appended to a file. (Default: off)
-[no-]diag-id-numbers
Tells the compiler to display diagnostic messages by using their ID number values (Default: on)
-f[no-]align-functions[=n]
Tells the compiler to align functions on an optimal byte boundary. (IA-32 and Intel® 64 architecture only, default: off)
-fast
Enables a set of options for improved performance. The options have changed in this release. Please see note below.
-f[no-]instrument-functions
Determines whether function entry and exit points are instrumented (Default: off)
-f[no]-keep-static-consts
Tells the compiler to preserve allocation of variables that are not referenced in the source (Default: off)
-[no-]fp-port
Tells the compiler to round floating point results to declared precision. This option was on by default in version 9.1 but is off by default in version 10.0 and later. Superseded by -fp:precise. (IA-32 and Intel® 64 architecture only, default: off)
-fp-speculation=<mode>
Tells the compiler the mode in which to speculate on floating-point operations (Default: fast)
-[no-]func-groups
Enables or disables function grouping if profiling information is enabled (IA-32 and Intel® 64 architecture only, default: off)
-gdwarf-2
Enables generation of debug information using the DWARF2 format (Default: off)
-heap-arrays[-]
Specifies that automatic arrays and arrays created for temporary computation should be allocated on the heap rather than the stack
-help [category]
Displays all available compiler options or a category of compiler options (Default: off)
-ipo-jobs<n>
Specifies the number of commands (jobs) to be executed simultaneously during the link phase of Interprocedural Optimization (IPO)
-march=<cpu>
Tells the compiler to generate code for a specified CPU (IA-32 and Intel® 64 architecture only, default: off)
-mia32
Tells the compiler to generate generic IA-32 architecture code, overriding any different default that the compiler may set. (IA-32 architecture only, default: off)
-msse[n]
Tells the compiler to generate code for certain Intel® processors (IA-32 and Intel® 64 architecture only, default: off for IA-32, -msse2 for Intel® 64 architecture)
-mtune=core2
Tells the compiler to choose optimizations that benefit the Intel® Core™2 processor family (IA-32 and Intel® 64 architecture only, default: off)
-openmp-lib type
Lets you specify an OpenMP* run-time library to use for linking. See note below. (Default: legacy)
-opt-jump-tables=default|never|large|<max-entries>
Controls the use of "jump tables" by the compiler. See below for more information. (Default: default)
-[no-]opt-loadpair
Enables or disables generation of loadpair code (IA-64 architecture only, default on)
-opt-malloc-options=n
Lets you specify an alternate algorithm for malloc(). (Default: 0)
-[no-]opt-mod-versioning
Enables or disables generation of alternate versions of code paths for modulo operations in cases where the modulo is a power of 2. (IA-64 architecture only, default: off)
-[no-]opt-multi-version-aggressive
Tells the compiler to use aggressive multi-versioning to check for pointer aliasing and scalar replacement. (IA-32 and Intel® 64 architecture only, default: off)
-[no-]opt-prefetch-initial-values
Enables or disables prefetch optimization prior to a loop for values which may be used within the first few iterations of the loop. (IA-64 architecture only, default: on)
-[no-]opt-prefetch-issue-excl-hint
Enables or disables use of the "exclusive" hint when generating prefetch instructions. (IA-64 architecture only, default: off)
-[no-]opt-prefetch-next-iteration
Enables or disables prefetch generation for memory accesses in the next iteration; typically used in a pointer-chasing loop. (IA-64 architecture only, default: on)
-opt-ra-region-strategy [=keyword]
Selects the method that the register allocator uses to partition each routine into regions. (IA-32 and Intel® 64 architecture only, default: default)
-opt-streaming-stores keyword
Enables generation of streaming stores for optimization. (IA-32 and Intel® 64 architecture only, default: auto)
-[no-]par-runtime-control
Generates code to perform run-time checks for loops that have symbolic loop bounds. (Default: off)
-no-prof-gen
Disables generation of profile information. (Negation form was not previously documented)
-prof-hotness-threshold=n
Lets you set the hotness threshold for function grouping and function ordering. See note below.
-no-prof-use
Disables use of profile information. (Negation form was not previously documented)
-par-schedule-<keyword>[=n]
Specifies a scheduling algorithm for DO loop iterations
-[no-]prefetch
Enables or disables the prefetch insertion optimization. Use on IA-32 architecture requires specifying -xT. (IA-32 and IA-64 architectures only, default: off)
-save-temps[-]
Tells the compiler to save intermediate files created during compilation (Default: off)
-shared-intel
Causes Intel-provided libraries to be linked in dynamically (Default: all libraries linked statically except libguide)
-shared-libgcc
Links the GNU libgcc library dynamically. (Default: off)
-static-intel
Causes Intel-provided libraries to be linked in statically (Default: all libraries linked statically except libguide)
-static-libgcc
Links the GNU libgcc library statically. (Default: off)
-std or -stand
Same as -std03 or -stand f03. Note that this is a change from previous versions. (Default: off)
-std03 or -stand f03
Tells the compiler to issue warnings for source syntax that does not conform to the Fortran 2003 standard. (Default: off)
-tcheck [<mode>]
Indicates the method of analysis to be performed for OpenMP threaded applications (Default: off)
-tcollect
Inserts instrumentation probes calling the Intel® Trace Collector API (Default: off)
-[no-]unroll-aggressive
Tells the compiler to use aggressive, complete unrolling for loops with small constant trip counts. default: off)
-[no-]vec-guard-write
Tells the compiler to perform a conditional check in a vectorized loop. (IA-32 and Intel® 64 architecture only, default: off)
-xO
Specifies that the compiler is to generate SSE3, SSE2 and SSE instructions and to optimize for the Intel® Pentium® 4 processor and Intel® Xeon® processor with SSE3. Generated code should operate on processors not made by Intel that support SSE3, SSE2 and SSE instruction sets, such as some AMD* processors. This value does not enable some optimizations enabled in the S, T, and P processor values. (IA-32 and Intel® 64 architecture only, default: off)
-xS
Specifies that the compiler is to generate SSE4 Vectorizing Compiler and Media Accelerators instructions for future Intel processors that support the instructions. This option also allows the compiler to generate SSSE3, SSE3, SSE2, and SSE instructions and it can optimize for future Intel processors. (IA-32 and Intel® 64 architecture only, default: off)

Deprecated and Removed Command Line Options

For information on command line options that are either deprecated (still functional but to be removed in a future version) or removed (no longer supported), please refer to the section Compiler Options > Deprecated and Removed Compiler Options in the on-disk documentation.

-opt-malloc-options=4

In version 10.1.008 the -opt-malloc-options compiler option was added. This specifies options to be used for calls to malloc() by means of a call to mallopt(). In version 10.1.008 the values 0 through 3 were defined. Version 10.1.009 adds a new value 4. The meanings of these values are shown below. For more information, please refer to the documentation for the C library routine mallopt().

  1. Tells the compiler to use the default options for malloc(). This is the default.
  2. Causes the following adjustments to the malloc() algorithm: M_MMAP_MAX=2 and M_TRIM_THRESHOLD=0x10000000.
  3. Causes the following adjustments to the malloc() algorithm: M_MMAP_MAX=2 and M_TRIM_THRESHOLD=0x40000000.
  4. Causes the following adjustments to the malloc() algorithm: M_MMAP_MAX=0 and M_TRIM_THRESHOLD=-1.
  5. Causes the following adjustments to the malloc() algorithm: M_MMAP_MAX=0, M_TRIM_THRESHOLD=-1, M_TOP_PAD=4096.

-opt-jump-tables=default|never|large|<max-entries>

This option allows user control for the size of jump tables generated by the compiler. Jump tables are used for switch statements. Switch statements are either implemented as jump tables or a series of if-then-else constructs. The method used typically have an impact on performance of the generated code, and on the size of the data area. Using jump tables will favor speed over size.

This option allows user control for the size of jump tables generated by the compiler. Jump tables are used for SELECT CASE constructs, which are implemented either as jump tables or a series of if-then-else constructs. The method used typically has an impact on performance of the generated code, and on the size of the data area. Using jump tables will favor speed over size.

The available values are:

default
Let the compiler decide. A jump table, a series of if-then-else constructs, or a combination is generated. The method used depends on factors such as number of cases in the construct and density of the cases. This is the default.
never
Never generate jump tables. Always use if-then-else constructs
large
Generate jump tables up to 65536 entries
<max-entries>
Generate jump tables up to <max-entries> in size

Meaning of -fast Changed

The -fast option is a shorter way of specifying a set of options that generally improve run-time performance. As documented, the set of options may change over time. In version 10.0, -fast sets -xT, whereas in earlier versions it set -xP. If this change is not appropriate for you, you must specify the individual options you want instead of using -fast. Please see the Compiler Options section of the on-disk documentation for further information.

Meaning of -stand Changed

In version 10.0, the meaning of the -stand option, when specified without a following keyword, is changed to mean -stand f03, or checking for conformance to Fortran 2003. You can select checking against Fortran 90 or Fortran 95 by specifying -stand f90 or -stand f95. -std is an alternate spelling of -stand. Note that the Intel® Fortran Language Reference still highlights Fortran 2003 features as extensions to Fortran 95.

-xW Enabled by Default on Intel® 64 Architecture Systems

On Intel® 64 architecture systems, -xW is enabled by default; this has the effect of enabling vectorization and you may see vectorization report messages displayed where you did not when using previous releases. To disable the vectorization report messages, use -diag-disable vec. You may still specify alternate options such as -xP or -axT.

New -prof-hotness-threshold=n option

This option lets you set the hotness threshold for function grouping and function ordering. The "hotness threshold" is the percentage of functions in the application that should be placed in the application's hot region. The hot region is the most frequently executed part of the application. By grouping these functions together into one hot region, they have a greater probability of remaining resident in the instruction cache. This can enhance the application's performance.

The argument n specifies the hotness threshold. n is a percentage having a value between 0 and 100 inclusive. If you specify 0, there will be no hotness threshold setting in effect for function grouping and function ordering. The default value is 10.

For this option to take effect, you must specify option -prof-use and either -prof-func-groups or -prof-func-order

Alternate Command Line Options

Many command line options have an older spelling where underscores (“_”) instead of hyphens (“-“) connect the words in the option name. The older spelling is still a valid alternate option name.

Support for gcc* OpenMP* Libraries

As of version 10.1 you can specify that OpenMP libraries compatible with gcc* 4.2 (or later) be used by specifying -openmp-lib compat. This may be desirable if your application contains some source modules built with gcc or g++ and your application uses OpenMP. The default is -openmp-lib legacy which uses the Intel-supplied OpenMP libraries that are not link-compatible with gcc OpenMP libraries.

Applications using the compat libraries must be built with version 10.0 or later of the Intel C++ and/or Fortran compilers with -openmp-lib compat specified.

In a future release, the default will change to -openmp-lib compat, and in a release after that, the legacy libraries will be removed.

Fortran 2003 Behaviors

Fortran 2003 defines behaviors for language features that were either extensions to previous standards or left unspecified in earlier standards. While version 10.1 of the Intel Fortran Compiler does not yet support all of Fortran 2003, the compiler now selects the Fortran 2003 behavior in some cases where earlier compiler versions chose a different behavior. In some other cases, the compiler defaults have not yet changed. These are described below.

Assignment to allocatable objects

In Fortran 95, assignment to an allocatable array required that the left and right hand side of the assignment match in shape and length parameters. In Fortran 2003, if the shapes and length parameters do not match, the variable being assigned to is deallocated and then reallocated to shape and length parameters matching the expression being assigned. As of version 10.1, the compiler can perform the extra actions specified by Fortran 2003, but as these can significantly hurt performance, the default is to retain the Fortran 95 behavior requiring that the shapes and length parameters match. If you want the Fortran 2003 behavior that deallocates and reallocates the variable on a shape mismatch, specify -assume realloc_lhs

Binary, octal and hexadecimal constants

In Fortran 95, binary, octal and hexadecimal constants ("BOZ constants") were allowed in DATA statements only and were restricted to initializing scalar integer variables. As an extension to Fortran 95, the Intel Fortran Compiler allowed BOZ constants in any context, with the type interpretation determined by the context. Fortran 2003 expands the use of BOZ constants permitting them to initialize any numeric type and in arguments to the INT, REAL, DBLE and CMPLX intrinsics.

The Fortran 2003 semantics for use of BOZ constants match the previous extended implementation of Intel Fortran except for the case of a BOZ constant as an argument to INT, REAL, DBLE and CMPLX. Fortran 2003 specifies that in these contexts a BOZ constant is interpreted as a binary value which is interpreted directly as the data type returned by the intrinsic, whereas the previous Intel Fortran interpretation was to treat the BOZ constant as a signed integer value which was then converted.

For example:

print *, real(Z'40490FDB')

with the old behavior (-assume old_boz) prints 1.0785300E+09 and with the new behavior (-assume noold_boz) prints 3.141593.

As of version 10.0, the default behavior for Intel Fortran is that of Fortran 2003, to transfer the binary value without conversion. If your application needs the old behavior, compile with the option -assume old_boz.

Default I/O unit *

In the Intel Fortran Compiler, I/O unit * and the implied units used by the ACCEPT, PRINT and TYPE statements, are by default associated with unit numbers distinct from those that could be specified in an OPEN statement, such as unit 5 or 6. Fortran 2003 requires that the programmer be able to OPEN these default units, which is incompatible with the current Intel Fortran behavior.

In version 10.0, the -assume [no]old_unit_star compile command option has been added to control this behavior. The default, -assume old_unit_star, retains the current and past behavior with unit * being distinct from units 5 and 6. If you want to use the Fortran 2003 behavior, or if you will be using the Fortran 2003 intrinsic module ISO_FORTRAN_ENV and its defined constants INPUT_UNIT and OUTPUT_UNIT, specify -assume noold_unit_star to have unit * (and ACCEPT, PRINT and TYPE) use units 5 (input) and 6 (output).

The default for this behavior may change in a future release.

RECL= unit for unformatted files

In version 10.0, as in versions 8.x and 9.x of Intel Fortran, when opening a file for unformatted I/O, the value specified for the RECL= keyword in OPEN is in four-byte units, the size of a default integer. Previous Fortran standards have said that the RECL= unit was "implementation-dependent", but Fortran 2003 "recommends" that it be single bytes. To specify that the RECL= unit for unformatted I/O be bytes, use the existing compiler option -assume byterecl. You must also use this option if your application uses the FILE_STORAGE_SIZE named constant from the intrinsic module ISO_FORTRAN_ENV.

.XOR. Intrinsic Operator

The Intel Fortran compiler defines, as an extension, an intrinsic operator .XOR.. This can cause conflicts with a user-defined operator of the same name as the intrinsic operator has a different precedence than user-defined operators. If you are definining your own operator .XOR. you can specify -assume no_old_xor to disable the compiler's definition of .XOR. as an intrinsic operator.

Global Symbol for Module Procedures and Variables

The Intel Fortran compiler constructs the global name for module procedures and variables by joining the module name with the procedure or variable name, separated with the string "_mp_", and then applying the standard name decoration rules. For example, a procedure SUB in module MYMOD would have a global name of MYMOD_mp_SUB. This method could conflict with a user procedure whose name contains the string _mp_. If your application has this conflict, specify the option -assume noold_mod_proc_name which will switch the case of the separator to be the opposite of the default name case. You must specify the same option for the entire application so that the names are consistent.

Stream I/O (Fortran 2003 feature)

As of version 10.1, the compiler supports the Fortran 2003 Stream I/O feature, which provides the ability to read and write files as a stream of bytes. To enable stream access, open the file specifying ACCESS='STREAM'. The READ and WRITE statements support a POS= keyword to specify file position. For more information, please refer to the Intel Fortran Compiler Language Reference.

Change in Behavior for RECORDTYPE='STREAMxx'

Intel Fortran has supported, as an extension, the RECORDTYPE values STREAM, STREAM_CR and STREAM_LF in the OPEN statement. In previous versions, neither the documentation nor the implementation were correct and the two were inconsistent. The old behavior was as follows:

RECORDTYPE='STREAM'
When writing, emits LF as a line terminator. On input, does not recognize delimiters.
RECORDTYPE='STREAM_CR'
When writing, emits CR-LF as a line terminator. On input, does not recognize delimiters.
RECORDTYPE='STREAM_LF'
When writing, emits CR-LF (Windows), LF (Linux* and Mac OS* X) as a line terminator. On input, does not recognize delimiters

Furthermore, if CARRIAGECONTROL='NONE' was specified, the behavior changed.

In version 10.1, the behavior changes as follows:

RECORDTYPE='STREAM'
No delimiter is written or read. Similar to Fortran 2003 Stream I/O
RECORDTYPE-'STREAM_CR'
Writes and reads CR as a record delimiter
RECORDTYPE='STREAM_LF'
Writes and reads LF as a record delimiter

A new option is defined as follows:

RECORDTYPE='STREAM_CRLF'
Writes and reads a CR-LF pair as a record delimiter

CARRIAGECONTROL no longer affects the behavior of RECORDTYPE.

On Windows, the default formatted record delimiter is CR-LF; on Linux and Mac OS* X it is LF. With these changes, it is now possible to specify a particular delimiter type on all three operating systems in a consistent fashion.

If you wish to change the run-time behavior of an application without editing the source, a new environment variable FOR_FMT_TERMINATOR can be defined. The value of this environment variable takes the form:

mode[:ulist][;mode[:ulist]...]

where mode is one of CR, LF or CRLF and ulist is an optional range of unit numbers to which that mode applies, for example, 2,17-20, 91

New Fortran 2003 Features

The following features from the Fortran 2003 standard have been added since the initial release of version 9.1. Some of these features first appeared in updates to version 9.1. For additional details, please see the Intel® Fortran Language Reference.

Additional Language Features

For details on the following new language features, please see the Intel® Fortran Language Reference

New Environment Variables to Specify Default Record Lengths

Two new environment variables are available to change the run-time behavior of applications: FORT_FMT_RECL and FORT_UFMT_RECL.

FORT_FMT_RECL is used to specify a default RECL (Record Length) value for all Fortran units opened for formatted I/O. If defined with an unsigned decimal integer value, the environment variable value is used as if that value had been specified for RECL= for OPEN when the RECORDTYPE is not 'FIXED'. The most common use of this is to change the line length for list-directed output, which has a default of 80 columns.

FORT_UFMT_RECL is used to specify a default RECL (Record Length) value for all Fortran units opened for unformatted I/O. If defined with an unsigned decimal integer value, the environment variable value is used as if that value had been specified for RECL= for OPEN when the RECORDTYPE is not 'FIXED'. The most common use of this is to change the maximum segment length for files opened with RECORDTYPE='SEGMENTED', which has a default of 2040 bytes.

KMP_AFFINITY Environment Variable for OpenMP* Applications

The KMP_AFFINITY environment variable can be used in an OpenMP* application to specify how execution threads should be bound to processors on the system. This setting's effect is to bind each thread, in order of creation, in a round-robin fashion to a processor core in the system for the duration of the program. The value of KMP_AFFINITY should be of the form:

compact,<level>

where <level> is a non-negative integer. For example:

compact,1

The argument <level> specifies the gap between successive thread's bound cores in the machine topology map, which is represented as a binary tree. A level of zero indicates that threads will be bound to successive threading contexts for processors which have Intel® Hyper-Threading Technology enabled, or successive processors if not. The levels increase by one level from threading contexts, to cores, to packages (processors) in sequence. This setting is supported for processors supplied by Intel Corporation only on systems where the required operating system support for thread binding is present.

Improved Parallelizer and Vectorizer

This version features a complete redesign of the optimizer that integrates parallelization (all architectures) and vectorization (IA-32 and Intel® 64 architectures) at O2 and O3 optimization levels with memory and loop optimizations.

Performance can be substantially improved by:

New and Enhanced Optimization Reports for Advanced Loop Transformations

Loop Transformation (HLO) Optimization reports tell you why the compiler was unable to apply loop interchange transformations on a set of loops and suggests loop interchange if the reported bottlenecks can be removed by source changes.   These reports have been enhanced to provide more detailed information and to be easier to understand.

Static Verifier

Static Verifier is a new compiler feature which performs static analysis of a program across multiple source files. It can detect different kinds of defects and doubtful or inconsistent uses of language features in user code and report them according to their severity level. Static Verifier understands C/C++ and Fortran code and can also perform analysis of OpenMP directives.

In this release, when Static Verifier is enabled the linker is not invoked so an executable or static/dynamic link library is not produced, object files that were produced as a result of invocation of Static Verifier are not valid and should not be used for generating of real executable or static/dynamic link libraries. The current usage model is that Static Verifier is added as an alternate build option to produce a diagnostic report.

Static Verifier cannot be used in conjunction with cross-file interprocedural optimization (/Qipo).

For more information, please refer to the section on Building Applications > Error Handling > Handling Compile Time Errors > using Static Verification Diagnostic Options in the on-disk documentation.

Fortran 2003 Feature Summary

The Intel Fortran Compiler supports many features that are new to the latest revision of the Fortran standard, Fortran 2003. Additional Fortran 2003 features will appear in future versions. Fortran 2003 features supported by the current compiler include:

Behavior Changes Planned for Future Compiler Versions

This section lists planned behavior changes in a future major release of the Intel® C++ Compiler

System Requirements

Processor Terminology

Intel® compilers support three platforms: general combinations of processor and operating system type. This section explains the terms that Intel uses to describe the platforms in its documentation, installation procedures and support site.

IA-32
IA-32 Architecture refers to systems based on 32-bit processors generally compatible with the Intel Pentium® II processor, (for example, Intel® Pentium® 4 processor or Intel® Xeon® processor), or processors from other manufacturers supporting the same instruction set, running a 32-bit operating system ("Linux x86").
Intel® 64
Intel® 64 Architecture refers to systems based on IA-32 architecture processors which have 64-bit architectural extensions, (for example, Intel® Core™2 processor family), running a 64-bit operating system ("Linux x86_64"). If the system is running a 32-bit version of the Linux operating system, then IA-32 architecture applies instead. Systems based on AMD* processors running a "Linux x86_64" operating system are also supported by Intel compilers for Intel® 64 architecture applications.
IA-64
Refers to systems based on the Intel® Itanium® processor running a 64-bit operating system.

Native and Cross-Platform Development

The term "native" refers to building an application that will run on the same platform that it was built on, for example, building on IA-32 architecture to run on IA-32 architecture. The term "cross-platform" or "cross-compilation" refers to building an application on a platform type different from the one on which it will be run, for example, building on IA-32 architecture to run on IA-64 architecture. Not all combinations of cross-platform development are supported and some combinations may require installation of optional tools and libraries.

The following list describes the supported combinations of compilation host (system on which you build the application) and application target (system on which the application runs).

IA-32 Architecture Host
Supported target: IA-32
Intel® 64 Architecture Host
Supported targets: IA-32 and Intel® 64
IA-64 Architecture Host
Supported target: IA-64

Note: Development for a target different from the host may require optional library components to be installed from your Linux Distribution.

Note: Intel® Cluster OpenMP* has different system requirements from that of the compilers. Please refer to the Intel Cluster OpenMP documentation for further details.

Requirements to develop IA-32 architecture applications

Requirements to Develop Applications for Intel® 64 Architecture Systems or for AMD* 64-bit Processors

Requirements to Develop IA-64 Architecture Applications

Note on gcc Versions

The Intel compilers are tested with a number of different Linux distributions, with different versions of gcc. Some Linux distributions may contain header files different from those we have tested, which may cause problems. The version of glibc you use must be consistent with the version of gcc in use. For best results, use only the gcc versions as supplied with distributions listed above.

Notes:

Installation

Please see the separate Installation Guide for information on installing the compiler and setting up the compiler environment. The default installation directories, referred to elsewhere in this document as <install-dir> and <idb-install-dir>, are:

Known Issues

Name Decoration Restored for BIND(C,NAME=)

If you specify the NAME= keyword for the BIND(C) attribute, the compiler should apply whatever name decoration rules, such as leading underscore, would be used by the C compiler for the same name. Some previous versions of the Intel Fortran Compiler did not apply this decoration, but the correct behavior was restored as of the January 2008 update. If you had added the decoration to the value of NAME= you will now need to remove it.

Binary Incompatibility for OpenMP Applications

Programs compiled with the Intel Compiler version 9.0 using the -openmp switch may not run after installing the Intel Compiler version 10.1. For such programs, the loader may exit at run time with an error message about undefined symbols beginning with the string _intel (for example, _intel_fast_memset). If this occurs, please recompile the executable using the Intel Compiler version 10.1 and the loader error message should disappear.

Installation Warning for RPM 4.0.2 and RPM 4.1

RPM 4.0.2 cannot install to a non-default directory. This has been resolved in RPM 4.0.3. RPM 4.1 cannot install to a non-default directory. This has been resolved in RPM 4.11 to 4.2.

Segmentation Violation with Static Link to libpthreads

Applications built with libpthreads.a statically linked, (libpthreads.a is used by default when -static is used), may fail with a segmentation violation on some versions of Linux when the applications use more than 2GB of stack space. This is a known limitation of Linuxthreads. If you encounter this problem, link libpthreads dynamically. As an alternative, on Red Hat Linux 9 and Red Hat Enterprise Linux 3.0, you can install the nptl-devel package and pass "-I/usr/include/nptl -L/usr/lib/nptl" on the ifort command line. This will create a statically-linked binary which will run under nptl only, but which does not have the stack size limitation.

OpenMP limitations

gprel relocation Error Messages on IA-64 Architecture Linux Systems

On IA-64 architecture systems running Linux, when the -shared switch is used to create a Dynamic Shared Object (.so), there may be some "relocation against dynamic symbol" messages generated during the ld phase, similar to:

/usr/bin/ld: for_init.o: @gprel relocation against dynamic symbol for__segv_default_msg
/usr/bin/ld: for_init.o: @gprel relocation against dynamic symbol for__l_fpe_mask
/usr/bin/ld: for_init.o: @gprel relocation against dynamic symbol for__l_undcnt
...

To fix this problem, add the switches -i_dynamic and -nofor_main to the command line. As of version 9.0, specifying -shared will automatically set -i_dynamic and -nofor_main.

-ipo_obj option is no longer supported

The -ipo_obj option, which forced generation of direct object code, is no longer supported. If the option is specified, a warning is given and the effect is as if -ip was specified instead.

-relax no longer passed to linker on IA-64 architecture systems

As of version 9.0, the compiler driver no longer passes the -relax switch to the linker on IA-64 architecture systems, as this conflicts with the -r option. The -relax option is not needed as it is the default when using binutils 2.11.90.0.27 or later - 2.14 is recommended. If you must use an older binutils and wish to specify the -relax option, use -Xlinker -relax on the compile command which invokes the linker.

ld warning about libunwind.so.7 on SLES 10

When applications are built using the Intel compiler on SUSE LINUX Enterprise Server 10, you may see a warning similar to the following:

ld: warning: libunwind.so.7, needed by /usr/lib/gcc/ia64-suse-linux/4.1.0/../../..//libgcc_s.so, may conflict with libunwind.so.6

A workaround is to add the following line to ifort.cfg:

-L /usr/lib

This issue is expected to be resolved in a future release of the Intel compiler.

Limited debug information with automatic CPU dispatching (-ax*)

Compilation using -ax[code] results in two copies of generated code for each function. One for generic code and one for CPU specific code. The symbol for each function then refers to an Auto CPU Dispatch routine that decides at run-time which one of the generated code sections to execute. Debugger breakpoints that are set on these functions by name cause the application to stop in the dispatch routine. This may cause unexpected behavior when debugging. This issue may be addressed in a future version of the Intel Debugger and Compilers.

Cannot debug or view traceback for IA-32 architecture programs built without -fp

Compilation using -fp specifies that the IA-32 architecture EBP register be used as a frame pointer rather than a general purpose register. Debuggers and traceback handlers may not be able to properly unwind through a stack that contains a call to a function that is compiled without -fp in effect. If you compile with -g or -O0, -fp is implicitly enabled, but not if you specify a higher optimization level explicitly (such as -O2). If you intend to use the debugger or traceback on an application, and are using some level of optimization higher than -O0, you should also specify -fp to ensure that the debugger and traceback handler can use frame pointers.

GNU assembler may not recognize generated code

Older versions of the GNU Assembler may not be able to process assembly code generated by compiling with the -[a]xP, T or S options. Use binutils version 2.17.50.0.15 or later if this is an issue for you.

Use idb with Extended Debug Information

If you use the -debug keywords inline_debug_info, semantic_stepping, variable_locations or extended, you should use the Intel Debugger (idb), as other debuggers may not understand the extended information and may behave unpredictably. We are working with the developers of other debuggers towards their adding support for the extended debug information.

-auto_ilp32 Option Not Supported

The -auto_ilp32 option which specifies that that an application cannot exceed a 32-bit address space, and which is mentioned in the documentation, is not supported.

Enabling Run-Time Checks May Also Enable Compile-Time Checks

In some cases, enabling run-time checks using the -check or -C option may cause the compiler to issue diagnostics for the requested condition at compile-time, if it can be diagnosed then. For example, an array bounds violation with a constant subscript may result in a compile-time error if -check bounds or -CB is specified.

Technical Support

If you did not register your compiler during installation, please do so at the Intel® Software Development Products Registration Center. Registration entitles you to free technical support, product updates and upgrades for the duration of the support term.

For information about how to find Technical Support, Product Updates, Users Forums, FAQs, tips and tricks, and other support information, please visit: http://www.intel.com/software/products/support/flin.

Note: If your distributor provides technical support for this product, please contact them for support rather than Intel.

Submitting Issues

Steps to submit an issue:

  1. Go to http://www.intel.com/software/products/support and click on the link for Intel® Premier Support.
  2. Log in to the site. Note that your username and password are case-sensitive.
  3. Click on the "Go" button next to the "Product" drop-down list.
  4. Click on the "Submit Issue" link in the left navigation bar.
  5. Choose "Development Environment (tools,SDV,EAP)" from the "Product Type" drop-down list.
  6. If this is a software or license-related issue, choose " Intel(R) Fortran Compiler for Linux*" from the "Product Name" drop-down list.
  7. Enter your question and complete the fields in the windows that follow to successfully submit the issue.

Note: Please notify your support representative prior to submitting source code where access needs to be restricted to certain countries to determine if this request can be accommodated.

Guidelines for problem report or product suggestion:

  1. Describe your difficulty or suggestion.
    For problem reports please be as specific as possible, so that we may reproduce the problem. For compiler problem reports, please include the compiler options and a small test case if possible.
  2. Describe your system configuration information.
    Get the version of glibc and kernel with following commands:
        > uname -a
        > rpm -qa | grep glibc
    If you don't have rpm installed, use the command below:
        > ls /lib/libc*
    and copy the information into the corresponding Intel® Premier Support fields.

    Get the Intel Fortran Compiler's Package ID with the following command:
        > ifort -V
    and copy the "Package ID" (e.g. l_fc_x_10.1.xxx) from the output into the corresponding Intel® Premier Support field. Please include any other specific information that may be relevant to helping us to reproduce and address your concern.

  3. If you were not able to install the compiler or cannot get the Package ID, enter the filename you downloaded as the package ID.

Resolved Issues

Please review <package ID>_README (e.g. l_fc_x_10.1.xxx_README), available for download from Intel® Software Development Products Registration Center Product Downloads, to see which issues have been resolved in the latest version of the compiler.

Compiler Error Source Reducer (CESR)

Compiler Error Source Reducer (CESR) is a set of utilities which are useful individually or collectively in gathering, reducing, pinpointing, protecting, documenting, and bundling test cases comprised of C/C++ or Fortran source code. It can be helpful if you have a large application for which you want to extract a small test case for submission to Intel® Premier Support. CESR can be downloaded from Intel® Software Development Products Registration Center Product Downloads. Select your product and in the version dropdown, select CESR. CESR is unsupported and should be considered experimental, but we welcome your feedback on it through Intel® Premier Support. CESR requires prior installation of Python* 2.2 or newer.

Documentation

You can view the Intel compiler and related HTML-based documentation with your Web browser. You should use a Web browser that supports JavaScript (such as Firefox*), so it can which provide full navigation, search, index look-up, and hyperlink capabilities amongst the online help files.

The documentation is installed in the <install-dir>/doc directory. An HTML index document can be found at <install-dir>/doc/Doc_Index.htm . The Intel® Debugger Manual is provided in HTML form in the Intel® Debugger doc directory.

Viewing Manpages

The ifort(1) manpage provides a list of command-line options and related information for the ifort compiler command. To display the ifort(1) manpage, type the following command after you set up your environment by using a source command to execute the <install-dir>/bin/ifortvars.*sh file:

$ man ifort

The man command provides single keys or key combinations that let you scroll through the displayed content, search for a string, jump to a location, and perform other functions. For example, type the z to view the next screen or w to view the previous screen. To obtain help about the man command, type the h key; when you are done viewing help, type the q key to return to the displayed manpage. To search, type / character followed by the search string (/string) and press Enter. After viewing the man command text, type q to return to the shell command prompt.

Viewing Documentation

The HTML documentation format has been tested to work with web browsers shipped on supported Linux* distributions. PDF versions of the compiler documentation are available at: http://developer.intel.com/software/products/compilers/flin/docs/manuals.htm

Additional Information

Related Products and Services

Information on Intel software development products is available at http://www.intel.com/software/products.

Some of the related products include:

Disclaimer and Legal Information

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The products described in this document may contain design defects or errors known as errata which may cause the product to deviate from published specifications. Current characterized errata are available on request.

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