[Bug target/61977] powerpc-eabi preprocessor breaks on lines that end with "vector"

["drivshin at allworx dot com" <gcc-bugzilla at gcc dot gnu dot org>]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=61977

David Rivshin <drivshin at allworx dot com> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Target|                            |powerpc-eabi
      Known to work|                            |4.9.0
      Known to fail|                            |4.9.1, 4.9.2

--- Comment #1 from David Rivshin <drivshin at allworx dot com> ---
This is still happening in the latest trunk and latest 4.9 branch code.

Simplified steps to reproduce:
../gcc.svn/configure --prefix=${PWD}/../local --enable-languages=c
--with-gnu-as --with-gnu-ld --disable-libstdcxx-pch --target=powerpc-eabi
--disable-shared --with-newlib
make all-gcc
make install-gcc
echo -e "# comment ending in vector" | ../local/bin/powerpc-eabi-cpp -x
assembler-with-cpp


I'm fairly certain this is the same root cause as bug 51654, and changeset
r210055 just exposed some non-altivec powerpc targets to it. In addition to the
workarounds mentioned there (bug 51654, comment 3), removing the call to
init_vector_keywords() in rs6000_cpu_cpp_builtins() also works. 

Since those vector keywords only have effect if TARGET_ALTIVEC (see
rs6000_macro_to_expand()), making their definition conditional upon
TARGET_ALTIVEC resolves the 4.9.1 regression (as best I can tell). Although
that obviously does not resolve the underlying issue, which has existed since
at least 4.6 (according to bug 51654).