Following instructions here: https://gcc.gnu.org/install/index.html on Fedora 28 with gcc (GCC) 8.1.1 20180712 (Red Hat 8.1.1-5). First, the build hit a couple of -Werror fails so I reconfigured with -disable-werror then I get: Comparing stages 2 and 3, Bootstrap comparison failure! Do I disable comparison? Disable bootstrap? Any other suggestions on doing a fresh build? > svn checkout svn://gcc.gnu.org/svn/gcc/trunk gcc > mkdir build > cd build > mkdir gcc > mkdir install > cd gcc > ../../gcc/configure --prefix=$HOME/repos/build/install --enable-languages=c,c++ --disable-multilib > make BOOT_CFLAGS='-O' bootstrap ... ./insn-opinit.h:358:40: error: ‘icode’ may be used uninitialized in this function [-Werror=maybe-uninitialized] 358 | #define GEN_FCN(CODE) (insn_data[CODE].genfun) ... ../../../gcc/gcc/config/i386/i386.c:4514:32: error: ‘mask’ may be used uninitialized in this function [-Werror=maybe-uninitialized] 4514 | opts->x_recip_mask_explicit |= mask; | ~~~~~~~~~~~~~~~~~~~~~~~~~~~~^~~~~~~ cc1plus: all warnings being treated as errors ... > make clean > ../../gcc/configure --prefix=$HOME/repos/build/install --enable-languages=c,c++ --disable-multilib -disable-werror > make ... Comparing stages 2 and 3 Bootstrap comparison failure! gcc/gcc.o differs gcc/plugin.o differs ...
