[CMake] How to use CMake with icc via configuration options when needing interprocedural optimization?

[Rolf Eike Beer]

> Thank you so much for the hint. Setting the environment variable CXX from
> within my CMakeLists.txt via
> SET(ENV{CXX} "icpc")
> but before any call to project() or enable_language() seems indeed to do
> the trick.
>
> Setting CMAKE_CXX_FLAGS_RELEASE or CMAKE_CXX_FLAGS_DEBUG at this stage
> however does not work. This apparently needs to go after the project()
> statement.
> I could of course set the environment cxx-flags in the same way as above.
> This would somewhat sacrifice the nice RELEASE / DEBUG distinction but
> maybe this can be done by some if-statements (there certainly is a way to
> query the CMAKE_BUILD_TYPE variable, right?).

if (CMAKE_BUILD_TYPE STREQUAL Debug) ...

But noone stops you to put another if(Intel) behind the project() call to
finish what you began before the project().

Eike