https://gcc.gnu.org/bugzilla/show_bug.cgi?id=66228
Bug ID: 66228 Summary: Compiling simple program with -flto -O1 causes mad behaviour Product: gcc Version: 4.9.2 Status: UNCONFIRMED Severity: normal Priority: P3 Component: lto Assignee: unassigned at gcc dot gnu.org Reporter: t...@the-tk.com Target Milestone: --- Created attachment 35582 --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=35582&action=edit This is the wtf.i file left over from running gcc -v -save-temps -flto -O1 wtf.c This code, when compiled with -O1 and -flto and ran with no arguments passed prints: ./a.out: Incorrect number of arguments ./a.out: WTF? And exits returning 1. This behaviour is obviously incorrect. This has been tested on versions (various people): 4.8.4 4.9.2 20150304 5.1.0 20150505 5.1.1 20150519 The version I am personally using is 4.9.2 20150304. Here is the output of `gcc -v -save-temps -flto -O1 wtf.c': Using built-in specs. COLLECT_GCC=/usr/bin/gcc COLLECT_LTO_WRAPPER=/usr/lib/gcc/x86_64-unknown-linux-gnu/4.9.2/lto-wrapper Target: x86_64-unknown-linux-gnu Configured with: /build/gcc/src/gcc-4.9-20150304/configure --prefix=/usr --libdir=/usr/lib --libexecdir=/usr/lib --mandir=/usr/share/man --infodir=/usr/share/info --with-bugurl=https://bugs.archlinux.org/ --enable-languages=c,c++,ada,fortran,go,lto,objc,obj-c++ --enable-shared --enable-threads=posix --with-system-zlib --enable-__cxa_atexit --disable-libunwind-exceptions --enable-clocale=gnu --disable-libstdcxx-pch --disable-libssp --enable-gnu-unique-object --enable-linker-build-id --enable-cloog-backend=isl --enable-lto --enable-plugin --enable-install-libiberty --with-linker-hash-style=gnu --disable-multilib --disable-werror --enable-checking=release Thread model: posix gcc version 4.9.2 20150304 (prerelease) (GCC) COLLECT_GCC_OPTIONS='-B' '/usr/lib/hardening-wrapper/bin' '-fPIE' '-D' '_FORTIFY_SOURCE=2' '-pie' '-fstack-protector-strong' '-v' '-save-temps' '-flto' '-O1' '-mtune=generic' '-march=x86-64' /usr/lib/gcc/x86_64-unknown-linux-gnu/4.9.2/cc1 -E -quiet -v -D _FORTIFY_SOURCE=2 wtf.c -mtune=generic -march=x86-64 -fPIE -fstack-protector-strong -flto -O1 -fpch-preprocess -o wtf.i ignoring nonexistent directory "/usr/lib/gcc/x86_64-unknown-linux-gnu/4.9.2/../../../../x86_64-unknown-linux-gnu/include" #include "..." search starts here: #include <...> search starts here: /usr/lib/gcc/x86_64-unknown-linux-gnu/4.9.2/include /usr/local/include /usr/lib/gcc/x86_64-unknown-linux-gnu/4.9.2/include-fixed /usr/include End of search list. COLLECT_GCC_OPTIONS='-B' '/usr/lib/hardening-wrapper/bin' '-fPIE' '-D' '_FORTIFY_SOURCE=2' '-pie' '-fstack-protector-strong' '-v' '-save-temps' '-flto' '-O1' '-mtune=generic' '-march=x86-64' /usr/lib/gcc/x86_64-unknown-linux-gnu/4.9.2/cc1 -fpreprocessed wtf.i -quiet -dumpbase wtf.c -mtune=generic -march=x86-64 -auxbase wtf -O1 -version -fPIE -fstack-protector-strong -flto -o wtf.s GNU C (GCC) version 4.9.2 20150304 (prerelease) (x86_64-unknown-linux-gnu) compiled by GNU C version 4.9.2 20150304 (prerelease), GMP version 6.0.0, MPFR version 3.1.2-p11, MPC version 1.0.2 warning: MPC header version 1.0.2 differs from library version 1.0.3. GGC heuristics: --param ggc-min-expand=100 --param ggc-min-heapsize=131072 GNU C (GCC) version 4.9.2 20150304 (prerelease) (x86_64-unknown-linux-gnu) compiled by GNU C version 4.9.2 20150304 (prerelease), GMP version 6.0.0, MPFR version 3.1.2-p11, MPC version 1.0.2 warning: MPC header version 1.0.2 differs from library version 1.0.3. GGC heuristics: --param ggc-min-expand=100 --param ggc-min-heapsize=131072 Compiler executable checksum: de1e8c8938fc18eb6d7bf643b5ef22cd COLLECT_GCC_OPTIONS='-B' '/usr/lib/hardening-wrapper/bin' '-fPIE' '-D' '_FORTIFY_SOURCE=2' '-pie' '-fstack-protector-strong' '-v' '-save-temps' '-flto' '-O1' '-mtune=generic' '-march=x86-64' as -v --64 -o wtf.o wtf.s GNU assembler version 2.25.0 (x86_64-unknown-linux-gnu) using BFD version (GNU Binutils) 2.25.0 COMPILER_PATH=/usr/lib/hardening-wrapper/bin/:/usr/lib/gcc/x86_64-unknown-linux-gnu/4.9.2/:/usr/lib/gcc/x86_64-unknown-linux-gnu/4.9.2/:/usr/lib/gcc/x86_64-unknown-linux-gnu/:/usr/lib/gcc/x86_64-unknown-linux-gnu/4.9.2/:/usr/lib/gcc/x86_64-unknown-linux-gnu/ LIBRARY_PATH=/usr/lib/hardening-wrapper/bin/:/usr/lib/gcc/x86_64-unknown-linux-gnu/4.9.2/:/usr/lib/gcc/x86_64-unknown-linux-gnu/4.9.2/../../../../lib/:/lib/../lib/:/usr/lib/../lib/:/usr/lib/gcc/x86_64-unknown-linux-gnu/4.9.2/../../../:/lib/:/usr/lib/ COLLECT_GCC_OPTIONS='-B' '/usr/lib/hardening-wrapper/bin' '-fPIE' '-D' '_FORTIFY_SOURCE=2' '-pie' '-fstack-protector-strong' '-v' '-save-temps' '-flto' '-O1' '-mtune=generic' '-march=x86-64' /usr/lib/gcc/x86_64-unknown-linux-gnu/4.9.2/collect2 -plugin /usr/lib/gcc/x86_64-unknown-linux-gnu/4.9.2/liblto_plugin.so -plugin-opt=/usr/lib/gcc/x86_64-unknown-linux-gnu/4.9.2/lto-wrapper -plugin-opt=-fresolution=wtf.res -plugin-opt=-pass-through=-lgcc -plugin-opt=-pass-through=-lgcc_s -plugin-opt=-pass-through=-lc -plugin-opt=-pass-through=-lgcc -plugin-opt=-pass-through=-lgcc_s -flto --build-id --eh-frame-hdr --hash-style=gnu -m elf_x86_64 -dynamic-linker /lib64/ld-linux-x86-64.so.2 -pie /usr/lib/gcc/x86_64-unknown-linux-gnu/4.9.2/../../../../lib/Scrt1.o /usr/lib/gcc/x86_64-unknown-linux-gnu/4.9.2/../../../../lib/crti.o /usr/lib/gcc/x86_64-unknown-linux-gnu/4.9.2/crtbeginS.o -L/usr/lib/hardening-wrapper/bin -L/usr/lib/gcc/x86_64-unknown-linux-gnu/4.9.2 -L/usr/lib/gcc/x86_64-unknown-linux-gnu/4.9.2/../../../../lib -L/lib/../lib -L/usr/lib/../lib -L/usr/lib/gcc/x86_64-unknown-linux-gnu/4.9.2/../../.. wtf.o -lgcc --as-needed -lgcc_s --no-as-needed -lc -lgcc --as-needed -lgcc_s --no-as-needed /usr/lib/gcc/x86_64-unknown-linux-gnu/4.9.2/crtendS.o /usr/lib/gcc/x86_64-unknown-linux-gnu/4.9.2/../../../../lib/crtn.o /usr/bin/gcc @/tmp/ccxHh0w0.args Using built-in specs. COLLECT_GCC=/usr/bin/gcc Target: x86_64-unknown-linux-gnu Configured with: /build/gcc/src/gcc-4.9-20150304/configure --prefix=/usr --libdir=/usr/lib --libexecdir=/usr/lib --mandir=/usr/share/man --infodir=/usr/share/info --with-bugurl=https://bugs.archlinux.org/ --enable-languages=c,c++,ada,fortran,go,lto,objc,obj-c++ --enable-shared --enable-threads=posix --with-system-zlib --enable-__cxa_atexit --disable-libunwind-exceptions --enable-clocale=gnu --disable-libstdcxx-pch --disable-libssp --enable-gnu-unique-object --enable-linker-build-id --enable-cloog-backend=isl --enable-lto --enable-plugin --enable-install-libiberty --with-linker-hash-style=gnu --disable-multilib --disable-werror --enable-checking=release Thread model: posix gcc version 4.9.2 20150304 (prerelease) (GCC) COLLECT_GCC_OPTIONS='-c' '-fno-trapv' '-fno-strict-overflow' '-mtune=generic' '-march=x86-64' '-O1' '-B' '/usr/lib/hardening-wrapper/bin' '-fPIE' '-D' '_FORTIFY_SOURCE=2' '-pie' '-fstack-protector-strong' '-v' '-save-temps' '-O1' '-mtune=generic' '-march=x86-64' '-fltrans-output-list=/tmp/cckzPbXh.ltrans.out' '-fwpa' '-fresolution=wtf.res' /usr/lib/gcc/x86_64-unknown-linux-gnu/4.9.2/lto1 -quiet -dumpbase wtf.o -mtune=generic -march=x86-64 -mtune=generic -march=x86-64 -auxbase wtf -O1 -O1 -version -fno-trapv -fno-strict-overflow -fPIE -fstack-protector-strong -fltrans-output-list=/tmp/cckzPbXh.ltrans.out -fwpa -fresolution=wtf.res @/tmp/ccOxcM5h GNU GIMPLE (GCC) version 4.9.2 20150304 (prerelease) (x86_64-unknown-linux-gnu) compiled by GNU C version 4.9.2 20150304 (prerelease), GMP version 6.0.0, MPFR version 3.1.2-p11, MPC version 1.0.2 warning: MPC header version 1.0.2 differs from library version 1.0.3. GGC heuristics: --param ggc-min-expand=100 --param ggc-min-heapsize=131072 GNU GIMPLE (GCC) version 4.9.2 20150304 (prerelease) (x86_64-unknown-linux-gnu) compiled by GNU C version 4.9.2 20150304 (prerelease), GMP version 6.0.0, MPFR version 3.1.2-p11, MPC version 1.0.2 warning: MPC header version 1.0.2 differs from library version 1.0.3. GGC heuristics: --param ggc-min-expand=100 --param ggc-min-heapsize=131072 COMPILER_PATH=/usr/lib/hardening-wrapper/bin/:/usr/lib/hardening-wrapper/bin/:/usr/lib/gcc/x86_64-unknown-linux-gnu/4.9.2/:/usr/lib/gcc/x86_64-unknown-linux-gnu/4.9.2/:/usr/lib/gcc/x86_64-unknown-linux-gnu/:/usr/lib/gcc/x86_64-unknown-linux-gnu/4.9.2/:/usr/lib/gcc/x86_64-unknown-linux-gnu/:/usr/lib/gcc/x86_64-unknown-linux-gnu/4.9.2/:/usr/lib/gcc/x86_64-unknown-linux-gnu/4.9.2/:/usr/lib/gcc/x86_64-unknown-linux-gnu/:/usr/lib/gcc/x86_64-unknown-linux-gnu/4.9.2/:/usr/lib/gcc/x86_64-unknown-linux-gnu/ LIBRARY_PATH=/usr/lib/hardening-wrapper/bin/:/usr/lib/gcc/x86_64-unknown-linux-gnu/4.9.2/../../../../lib/../lib/:/lib/../lib/../lib/:/usr/lib/../lib/../lib/:/usr/lib/gcc/x86_64-unknown-linux-gnu/4.9.2/../../../../lib/:/lib/../lib/:/usr/lib/../lib/:/usr/lib/gcc/x86_64-unknown-linux-gnu/4.9.2/:/usr/lib/gcc/x86_64-unknown-linux-gnu/4.9.2/../../../../lib/:/lib/../lib/:/usr/lib/../lib/:/usr/lib/hardening-wrapper/bin/:/usr/lib/gcc/x86_64-unknown-linux-gnu/4.9.2/:/usr/lib/gcc/x86_64-unknown-linux-gnu/4.9.2/../../../../lib/:/lib/../lib/:/usr/lib/../lib/:/usr/lib/gcc/x86_64-unknown-linux-gnu/4.9.2/../../../:/lib/:/usr/lib/:/usr/lib/gcc/x86_64-unknown-linux-gnu/4.9.2/../../../:/lib/:/usr/lib/ COLLECT_GCC_OPTIONS='-c' '-fno-trapv' '-fno-strict-overflow' '-mtune=generic' '-march=x86-64' '-O1' '-B' '/usr/lib/hardening-wrapper/bin' '-fPIE' '-D' '_FORTIFY_SOURCE=2' '-pie' '-fstack-protector-strong' '-v' '-save-temps' '-O1' '-mtune=generic' '-march=x86-64' '-fltrans-output-list=/tmp/cckzPbXh.ltrans.out' '-fwpa' '-fresolution=wtf.res' [Leaving LTRANS /tmp/ccxHh0w0.args] [Leaving LTRANS /tmp/cckzPbXh.ltrans.out] /usr/bin/gcc @/tmp/ccUKvuJr.args Using built-in specs. COLLECT_GCC=/usr/bin/gcc Target: x86_64-unknown-linux-gnu Configured with: /build/gcc/src/gcc-4.9-20150304/configure --prefix=/usr --libdir=/usr/lib --libexecdir=/usr/lib --mandir=/usr/share/man --infodir=/usr/share/info --with-bugurl=https://bugs.archlinux.org/ --enable-languages=c,c++,ada,fortran,go,lto,objc,obj-c++ --enable-shared --enable-threads=posix --with-system-zlib --enable-__cxa_atexit --disable-libunwind-exceptions --enable-clocale=gnu --disable-libstdcxx-pch --disable-libssp --enable-gnu-unique-object --enable-linker-build-id --enable-cloog-backend=isl --enable-lto --enable-plugin --enable-install-libiberty --with-linker-hash-style=gnu --disable-multilib --disable-werror --enable-checking=release Thread model: posix gcc version 4.9.2 20150304 (prerelease) (GCC) COLLECT_GCC_OPTIONS='-c' '-fno-trapv' '-fno-strict-overflow' '-mtune=generic' '-march=x86-64' '-O1' '-B' '/usr/lib/hardening-wrapper/bin' '-fPIE' '-D' '_FORTIFY_SOURCE=2' '-pie' '-fstack-protector-strong' '-v' '-save-temps' '-O1' '-mtune=generic' '-march=x86-64' '-fltrans-output-list=/tmp/cckzPbXh.ltrans.out' '-fltrans' '-o' '/tmp/cckzPbXh.ltrans0.ltrans.o' /usr/lib/gcc/x86_64-unknown-linux-gnu/4.9.2/lto1 -quiet -dumpbase cckzPbXh.ltrans0.o -mtune=generic -march=x86-64 -mtune=generic -march=x86-64 -auxbase-strip /tmp/cckzPbXh.ltrans0.ltrans.o -O1 -O1 -version -fno-trapv -fno-strict-overflow -fPIE -fstack-protector-strong -fltrans-output-list=/tmp/cckzPbXh.ltrans.out -fltrans @/tmp/ccNoDh2g -o cckzPbXh.ltrans0.s GNU GIMPLE (GCC) version 4.9.2 20150304 (prerelease) (x86_64-unknown-linux-gnu) compiled by GNU C version 4.9.2 20150304 (prerelease), GMP version 6.0.0, MPFR version 3.1.2-p11, MPC version 1.0.2 warning: MPC header version 1.0.2 differs from library version 1.0.3. GGC heuristics: --param ggc-min-expand=100 --param ggc-min-heapsize=131072 GNU GIMPLE (GCC) version 4.9.2 20150304 (prerelease) (x86_64-unknown-linux-gnu) compiled by GNU C version 4.9.2 20150304 (prerelease), GMP version 6.0.0, MPFR version 3.1.2-p11, MPC version 1.0.2 warning: MPC header version 1.0.2 differs from library version 1.0.3. GGC heuristics: --param ggc-min-expand=100 --param ggc-min-heapsize=131072 COLLECT_GCC_OPTIONS='-c' '-fno-trapv' '-fno-strict-overflow' '-mtune=generic' '-march=x86-64' '-O1' '-B' '/usr/lib/hardening-wrapper/bin' '-fPIE' '-D' '_FORTIFY_SOURCE=2' '-pie' '-fstack-protector-strong' '-v' '-save-temps' '-O1' '-mtune=generic' '-march=x86-64' '-fltrans-output-list=/tmp/cckzPbXh.ltrans.out' '-fltrans' '-o' '/tmp/cckzPbXh.ltrans0.ltrans.o' as -v --64 -o /tmp/cckzPbXh.ltrans0.ltrans.o cckzPbXh.ltrans0.s GNU assembler version 2.25.0 (x86_64-unknown-linux-gnu) using BFD version (GNU Binutils) 2.25.0 COMPILER_PATH=/usr/lib/hardening-wrapper/bin/:/usr/lib/hardening-wrapper/bin/:/usr/lib/gcc/x86_64-unknown-linux-gnu/4.9.2/:/usr/lib/gcc/x86_64-unknown-linux-gnu/4.9.2/:/usr/lib/gcc/x86_64-unknown-linux-gnu/:/usr/lib/gcc/x86_64-unknown-linux-gnu/4.9.2/:/usr/lib/gcc/x86_64-unknown-linux-gnu/:/usr/lib/gcc/x86_64-unknown-linux-gnu/4.9.2/:/usr/lib/gcc/x86_64-unknown-linux-gnu/4.9.2/:/usr/lib/gcc/x86_64-unknown-linux-gnu/:/usr/lib/gcc/x86_64-unknown-linux-gnu/4.9.2/:/usr/lib/gcc/x86_64-unknown-linux-gnu/ LIBRARY_PATH=/usr/lib/hardening-wrapper/bin/:/usr/lib/gcc/x86_64-unknown-linux-gnu/4.9.2/../../../../lib/../lib/:/lib/../lib/../lib/:/usr/lib/../lib/../lib/:/usr/lib/gcc/x86_64-unknown-linux-gnu/4.9.2/../../../../lib/:/lib/../lib/:/usr/lib/../lib/:/usr/lib/gcc/x86_64-unknown-linux-gnu/4.9.2/:/usr/lib/gcc/x86_64-unknown-linux-gnu/4.9.2/../../../../lib/:/lib/../lib/:/usr/lib/../lib/:/usr/lib/hardening-wrapper/bin/:/usr/lib/gcc/x86_64-unknown-linux-gnu/4.9.2/:/usr/lib/gcc/x86_64-unknown-linux-gnu/4.9.2/../../../../lib/:/lib/../lib/:/usr/lib/../lib/:/usr/lib/gcc/x86_64-unknown-linux-gnu/4.9.2/../../../:/lib/:/usr/lib/:/usr/lib/gcc/x86_64-unknown-linux-gnu/4.9.2/../../../:/lib/:/usr/lib/ COLLECT_GCC_OPTIONS='-c' '-fno-trapv' '-fno-strict-overflow' '-mtune=generic' '-march=x86-64' '-O1' '-B' '/usr/lib/hardening-wrapper/bin' '-fPIE' '-D' '_FORTIFY_SOURCE=2' '-pie' '-fstack-protector-strong' '-v' '-save-temps' '-O1' '-mtune=generic' '-march=x86-64' '-fltrans-output-list=/tmp/cckzPbXh.ltrans.out' '-fltrans' '-o' '/tmp/cckzPbXh.ltrans0.ltrans.o' [Leaving LTRANS /tmp/ccUKvuJr.args] [Leaving LTRANS /tmp/cckzPbXh.ltrans0.o]