Get Started with the Intel® Fortran Compiler Classic and Intel® Fortran Compiler

ID 767260
Date 3/22/2024

Get Started with the Intel® Fortran Compiler Classic and Intel® Fortran Compiler


Intel® Fortran Compiler Classic (ifort) is now deprecated and will be discontinued in October 2024. Intel recommends that customers transition now to using the LLVM-based Intel® Fortran Compiler (ifx) for continued Windows* and Linux* support, new language support, new language features, and optimizations.

For the latest information on transitioning from ifort to ifx, see the Porting Guide for ifort Users to ifx.

The Intel® Fortran Compiler Classic and Intel® Fortran Compiler provide optimizations that help your applications to run faster on Intel® 64, and IA-32 architectures, with support for the latest Fortran language standards. This compiler produces optimized code that can run significantly faster by taking advantage of the ever-increasing core count and vector register width in Intel® Xeon® processors and compatible processors. The Intel® Compiler will help you boost application performance through superior optimizations and Single Instruction Multiple Data (SIMD) vectorization, integration with Intel® Performance Libraries, and by leveraging the OpenMP* 5.0/5.1 parallel programming model.

Start using the compiler from the command line or within Microsoft Visual Studio*.

  • macOS is no longer supported for Intel® Fortran Compiler Classic (ifort).
  • Support for 32-bit targets is deprecated in ifort and may be removed in a future release. ifx does not support 32-bit targets.

Use of the Intel® Fortran Compiler

The Intel® Fortran Compiler (ifx) is a new compiler based on the Intel® Fortran Compiler Classic (ifort) frontend and runtime libraries, using LLVM backend technology. At this time, ifx supports features of the Fortran 95 language, and most OpenMP 5.0/5.1 directives and offloading features. ifx is binary (.o/.obj) and module (.mod) file compatible; binaries and libraries generated with ifort can be linked with binaries and libraries built with ifx, and .mod files generated with one compiler can be used by the other. Both compilers use the ifort runtime libraries.

The -fp-model fast and -fp-model fast=2 options behave differently with ifx and ifort. With ifort, floating point compares happen as specified by the IEEE floating point standard, in that the code sequence generated for them assumes a compare can involve a NaN. ifx does not generate the check for NaN operands. If using -fp-model fast or -fp-model fast=2 with ifx and NaN compares are desired to match ifort's behavior, the -assume nan_compare option should be added to the command line.

Find More


Explore the complete list of oneAPI code samples in the oneAPI Samples Catalog (GitHub*). These samples were designed to help you develop, offload, and optimize multiarchitecture applications targeting CPUs, GPUs, and FPGAs.

Document Description

Intel® Fortran Compiler Classic and Intel® Fortran Compiler Developer Guide and Reference

The Developer Guide and Reference contains information on:

  • How to use the command line or Microsoft* Visual Studio*or Xcode*or the Eclipse* CDT
  • Support for the latest compiler technologies and architectures.
  • Compiler reference material, including options, program structures, class and math libraries, and much more

Intel® Fortran Compiler Documentation

Explore tutorials, training materials, and other Fortran documentation.

Intel® Fortran Compiler Classic and Intel® Fortran Compiler Release Notes

Information on product installation, new and changed features, and issues that are not described in the product documentation.

Intel® Fortran Compiler Forum

Ask questions and find answers in the Intel® Fortran Compiler forum.

Layers for Yocto* Project

Add oneAPI components to a Yocto project build using the meta-intel layers.

Notices and Disclaimers

Intel, the Intel logo, Intel Atom, Intel Core, Intel Xeon Phi, VTune and Xeon are trademarks of Intel Corporation in the U.S. and/or other countries.

*Other names and brands may be claimed as the property of others.

Microsoft, Windows, and the Windows logo are trademarks, or registered trademarks of Microsoft Corporation in the United States and/or other countries.

© Intel Corporation.

This software and the related documents are Intel copyrighted materials, and your use of them is governed by the express license under which they were provided to you (License). Unless the License provides otherwise, you may not use, modify, copy, publish, distribute, disclose or transmit this software or the related documents without Intel's prior written permission.

This software and the related documents are provided as is, with no express or implied warranties, other than those that are expressly stated in the License.

Intel optimizations, for Intel compilers or other products, may not optimize to the same degree for non-Intel products.