[Bug optimization/12209] New: GCC fails to bootstrap Cygwin with -funit-at-a-time

["kcook at gcc dot gnu dot org" <gcc-bugzilla at gcc dot gnu dot org>]

PLEASE REPLY TO gcc-bugzilla@gcc.gnu.org ONLY, *NOT* gcc-bugs@gcc.gnu.org.

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=12209

           Summary: GCC fails to bootstrap Cygwin with -funit-at-a-time
           Product: gcc
           Version: 3.4
            Status: UNCONFIRMED
          Keywords: build
          Severity: normal
          Priority: P2
         Component: optimization
        AssignedTo: hubicka at gcc dot gnu dot org
        ReportedBy: kcook at gcc dot gnu dot org
                CC: gcc-bugs at gcc dot gnu dot org
 GCC build triplet: i686-pc-cygwin
  GCC host triplet: i686-pc-cygwin
GCC target triplet: i686-pc-cygwin

When -funit-at-a-time is used for bootstrap, as is now the default since has
been added to -O2, Cygwin ICEs when compiling __popcountsi2 for libgcc2 after
the stage2 compiler is built.

The workaround is 

make BOOT_CFLAGS="-O2 -fno-unit-a-time -g" bootstrap

which will work.