How do I enable link time optimization (LTO) with CMake?

Question

I have the most recent cmake build and trying all build configurations (Debug, MinSizeRel, RelWithDebugInfo, Release, General) I see nowhere (text search) in generated makefiles

Answer 1

Edit: as of 28 October, 2015 on CMake IRC

jcelerier | I have a question about INTERPROCEDURAL_OPTIMIZATION
jcelerier | it sounds like it should enable -flto on gcc
+ngladitz | jcelerier: its only implemented for the intel compiler
jcelerier | ngladitz: ah, okay
jcelerier | are there other switches for pgo / lto ?
jcelerier | or must it be done by hand ?
+ngladitz | there currently is no first class support otherwise     

Related CMake issue: https://gitlab.kitware.com/cmake/cmake/issues/15245

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CMake has the INTERPROCEDURAL_OPTIMIZATION property on targets, which sounds like it may enable LTO on some platforms.

Link : http://www.cmake.org/cmake/help/v3.0/prop_tgt/INTERPROCEDURAL_OPTIMIZATION.html

To enable it on a target MyLib :

add_library(MyLib ...)
...
set_property(TARGET MyLib PROPERTY INTERPROCEDURAL_OPTIMIZATION True)