https://gcc.gnu.org/bugzilla/show_bug.cgi?id=61207
M. Hanselmann <public at hansmi dot ch> changed: What |Removed |Added ---------------------------------------------------------------------------- CC| |public at hansmi dot ch --- Comment #5 from M. Hanselmann <public at hansmi dot ch> --- This also happens when compiling Boost 1.57.0. I've reproduced it using TDM64-GCC (version 4.9.2-3) and Stephan T. Lavavej's MinGW distribution (version 12.2). How to reproduce: - Unpack Boost 1.57.0 and change into source directory - g++ -v -save-temps -Os -I. libs\test\src\unit_test_parameters.cpp As mentioned in earlier comments, -O{1,2,3} work and only -Os produced an ICE. I'm not attaching 2.3 MB preprocessed file due to the wide availability of Boost sources.