Mingw x64 Windows: plugin needed to handle lto object

Question

When I'm trying to compile my project with 64-bit mingw (x86_64-5.1.0-posix-seh-rt_v4-rev0) I got messages:

BFD: my/project/dir/filename.cpp.obj: plugin needed to handle lto object

for each source file. Yet when I compile with 32-bit mingw(i686-5.1.0-posix-dwarf-rt_v4-rev0), everething is OK.

My flags are:

CXX_FLAGS "-fno-exceptions -fno-rtti -std=c++14 -O3 -fstrict-aliasing -flto -fomit-frame-pointer -march=native -ffast-math -funroll-loops"
LINKER_FLAGS "-O1 -s"

I tried to add -fuse-linker-plugin and -fno-use-linker-plugin, but it didn't help. My OS is 64-bit Windows 10. I use CLion and CMake if it matters, though it shouldn't. How can I fix it?

Answer 1

Put the LTO plugin into the bfd-plugins directory:

mkdir mingw64\lib\bfd-plugins
cp mingw64\libexec\gcc\x86_64-w64-mingw32\5.1.0\liblto_plugin-0.dll mingw64\lib\bfd-plugins\liblto_plugin-0.dll