other: 0.888
instruction: 0.873
socket: 0.853
graphic: 0.840
mistranslation: 0.839
semantic: 0.832
device: 0.824
network: 0.818
assembly: 0.816
vnc: 0.814
KVM: 0.755
boot: 0.718

Qemu 2.3.0 failes to compile with GCC 5.1.0 and -flto

Compiling Qemu 2.3.0 failes with the following error:

x86_64-pc-linux-gnu-g++ -I/usr/include/pixman-1   -fPIE -DPIE -m64 -D_GNU_SOURCE -D_FILE_OFFSET_BITS=64 -D_LARGEFILE_SOURCE -Wstrict-prototypes -Wredundant-decls -Wall -Wundef -Wwrite-strings -Wmissing-prototypes -fno-strict-aliasing -fno-common  -Wendif-labels -Wmissing-include-dirs -Wempty-body -Wnested-externs -Wformat-security -Wformat-y2k -Winit-self -Wignored-qualifiers -Wold-style-declaration -Wold-style-definition -Wtype-limits -fstack-protector-strong   -I/usr/include/libpng16  -I/usr/include/libusb-1.0  -I/home/gentoo/tmp/portage/app-emulation/qemu-2.3.0/work/qemu-2.3.0/tests -pthread -I/usr/include/glib-2.0 -I/usr/lib64/glib-2.0/include  -march=native -O2 -pipe -ggdb -floop-interchange -floop-strip-mine -floop-block -ftree-loop-distribution -fira-loop-pressure -ftree-vectorize -ftree-loop-linear -flto=5 -fuse-linker-plugin -Wl,-z,relro -Wl,-z,now -pie -m64 -Wl,-O1 -Wl,--as-needed -march=native -O2 -pipe -ggdb -floop-interchange -floop-strip-mine -floop-block -ftree-loop-distribution -fira-loop-pressure -ftree-vectorize -ftree-loop-linear -flto=5 -fuse-linker-plugin -Wl,-znow -Wl,--sort-common -Wl,--hash-style=gnu -Wl,--enable-new-dtags -o qemu-img qemu-img.o async.o thread-pool.o nbd.o block.o blockjob.o main-loop.o iohandler.o qemu-timer.o aio-posix.o qemu-io-cmds.o qemu-coroutine.o qemu-coroutine-lock.o qemu-coroutine-io.o qemu-coroutine-sleep.o coroutine-ucontext.o block/raw_bsd.o block/qcow.o block/vdi.o block/vmdk.o block/cloop.o block/dmg.o block/bochs.o block/vpc.o block/vvfat.o block/qcow2.o block/qcow2-refcount.o block/qcow2-cluster.o block/qcow2-snapshot.o block/qcow2-cache.o block/qed.o block/qed-gencb.o block/qed-l2-cache.o block/qed-table.o block/qed-cluster.o block/qed-check.o block/vhdx.o block/vhdx-endian.o block/vhdx-log.o block/parallels.o block/blkdebug.o block/blkverify.o block/block-backend.o block/snapshot.o block/qapi.o block/raw-posix.o block/linux-aio.o block/null.o block/mirror.o block/nbd.o block/nbd-client.o block/sheepdog.o block/accounting.o block/write-threshold.o block/curl.o  libqemuutil.a libqemustub.a   -lz -lbz2 -laio -lcurl -lm -lgthread-2.0 -pthread -lglib-2.0   -lz -lrt -lz -lcap-ng -luuid  -lutil
lto1: error: two or more sections for .gnu.lto_fprintf.2f4a95b725db6827
(null):0: confused by earlier errors, bailing out
make[1]: *** [/home/gentoo/tmp/portage/app-emulation/qemu-2.3.0/temp/ccEUT6Vq.ltrans11.ltrans.o] Error 1
make[1]: *** Waiting for unfinished jobs....
lto-wrapper: fatal error: make returned 2 exit status
compilation terminated.
/usr/lib/gcc/x86_64-pc-linux-gnu/5.1.0/../../../../x86_64-pc-linux-gnu/bin/ld: fatal error: lto-wrapper failed
collect2: error: ld returned 1 exit status
/home/gentoo/tmp/portage/app-emulation/qemu-2.3.0/work/qemu-2.3.0/rules.mak:122: recipe for target 'qemu-img' failed
make: *** [qemu-img] Error 1

I've found an old GCC bugreport with the same error: https://gcc.gnu.org/bugzilla/show_bug.cgi?id=52159 (which has been marked as dup of https://gcc.gnu.org/bugzilla/show_bug.cgi?id=59000) . I was able to reduce the object list to to three .o files which reproduce the error reliably: qemu-img.o qemu-io-cmds.o block/qapi.o.

Please let me know if you need further information.

This seems to be a GCC bug, not a QEMU bug? I'm going to close this bug, since it has been reported upstream with the GCC folks, and they don't seem to think this is an error on our side.