Intel® C++ Compiler Classic Release Notes

By Varsha Madananth,

Published: 09/17/2019   Last Updated: 06/04/2021

This document provides a summary of new and changed product features and includes notes about features and problems not described in the product documentation.

This Release Note will only cover Intel® C++ Compiler Classic.


Key Features in oneAPI C++ Compiler Classic 2021.3

  • Bug fixes

Key Features in oneAPI C++ Compiler Classic 2021.2.1


  • Bug fixes
  • Support for Microsoft Visual Studio* 2019 16.9.3.This release fixes calls to math builtin function which caused linker issue with  VS 2019 v16.9.3.  This allows the Intel C++ Compiler Classic to work with VS 2019 16.9.3.  C++ Users with VS 2019 update 16.9.3 should install this patch to fix the link issue.

Important Note -

  • This 2021.2.1 is a PATCH release. If you use Intel Fortran please do NOT install this patch Release as it will break any existing Intel® Fortran Compiler Classic and Intel® Fortran Compiler (Beta) 2021.x that is installed on your system
  • The 2021.2.1 Release is for Windows* only, C++ only, and a fix only for the Intel® C++ Compiler Classic only.  DPC++ and ICX users do not need this release since it contains no new fixes or features from 2021.2.0.
  • The 2021.2.1 Release is only provided by an online download HERE .  This Release is not provided on the Intel® Registration Center and not in the NuGET repository.

Key Features in oneAPI C++ Compiler Classic 2021.2

  • Support for Alderlake and Sapphir Rapids features through compiler options - 
    • -mavxvnni
    • -mcldemote
    • -mhreset
    • -mptwrite
    • -mserialize
    • -mwaitpkg
    • -march=alderlake, -xalderlake 

    • -march=sapphirerapids, ​-xsapphirerapids

  • Corrections to reported problems

New Features in oneAPI C++ Compiler Classic 2021.1.2 Patch release

  • This 2021.1.2 is a PATCH release.  It is not a full compiler and relies on updating an existing one.  It is intended to install over an existing oneAPI HPC Toolkit 2021.1.1 installation.
  • This patch release fixes the issue Compiler Option --version Incorrect Version String. There are no other fixes in this compiler compared to the initial release 2021.1.1 compiler.
  • When installing a patch release, users to install the latest patches for all the compilers that they use(Intel Fortran Compiler/Intel DPC++/C++ Compiler/Intel C++ Compiler classic).
  • Intel® CPU Runtime for OpenCL™ Applications is also required to be re-installed. You can download the Intel® CPU Runtime for OpenCL™ Applications for Windows from here. For Linux, the package is distributed through APT and YUM, please follow the instructions on Installing Intel® oneAPI Toolkits via Linux* Package Managers to setup the repository and install the package "intel-oneapi-runtime-opencl".

Key Features in oneAPI C++ Compiler Classic 2021.1

  • New C++20 features supported under the /Qstd=c++20 (Windows*) or -std=c++20 (Linux*/OS X*) options.
  • New features from OpenMP 5.0*  
    • IF clause on SIMD Directive
    • NONTEMPORAL clause on SIMD directive
  • Compiler option --version Incorrect version string 
  • Corrections to reported problems


How to install the Intel® C++ Compiler classic

Installation instructions are shipped with all Intel® Software Development Products as part of the documentation. Installation guide for the latest Intel® oneAPI HPC toolkit version is also available online. Please check Intel® oneAPI page for installation guides.


How to use the Intel® C++ Compiler Classic

Please refer to

for details on how to use the Intel® C++ Compiler Classic.


Unsupported or Discontinued Features


The Loop Profiler feature will be removed in future compilers.

The following compiler options related to Loop Profiler are deprecated and will be removed in future compilers

  • profile-loops=keyword
  • profile-loops-report=value
  • profile-functions
  • guide-profile

Intel® Cilk™ Plus support is removed

ICC -qnextgen compiler option is removed
Use of qnextgen (Linux), /qnextgen (Windows) compiler option is removed. Use "icx", instead of "icc -qnextgen" or "icc /qnextgen".

The Intel® C++ Compiler  (icx) is available as "Intel® oneAPI DPC++/C++ Compiler" in Intel® oneAPI Base Toolkit  release.

OpenMP offload is available as "Intel® oneAPI DPC++/C++ Compiler Pro" in Intel® oneAPI HPC Toolkit.

Please refer to  Intel® oneAPI DPC++/C++ Compiler Release Notes for new Feature on Intel® C++ Compiler  (icx) and OpenMP offload.

Known Issues

Compiler Option --version Incorrect Version String

Compiler option --version on Linux* and macOS* returns an incorrect version string icc (ICC) 2021.1 Beta 20201112.  The word "Beta" is incorrect; this is a production compiler. Use the compiler option -V for the correct version string, Intel(r) C++ Intel (r) 64 Compiler Classic for applications running on Intel (r) 64, Version 2021.1 Build 20201112_000000. The string returned by compiler option --version is fixed in the 2021.1.2 Patch release. This icc compiler option is not available on Windows*.

macOS Big Sur 11 Not Supported

Errors will be missing libraries such as -lSystem not found

More background: New in macOS Big Sur 11.0.1, the system ships with a built-in dynamic linker cache of all system-provided libraries. As part of this change, copies of dynamic libraries are no longer present on the filesystem. Code that attempts to check for dynamic library presence by looking for a file at a path or enumerating a directory will fail.

Error "no rule to process file" within Xcode* 10 and 11

macOS*’s XCode 10 and 11 come with a new build system and it is configured as the default. Currently, the Intel Compiler does not support it. You will see the error "no rule to process file" when building an Intel C++ Compiler project within XCode. Please switch to “Legacy Build System” in Project Settings to build your  project in Xcode.

For more details please find this article.


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Product and Performance Information


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