While trying to build the GCC 5 with GCC 5, I ran into an ICE when
building libcpp at -O0.  The problem is the C++ front-end was not
folding sizeof(a)/sizeof(a[0]) when passed to a function at -O0. The
C++ front-end keeps around sizeof until the gimplifier and there is no
way to fold the expressions that involve them.  So to work around the
issue we need to change __builtin_aarch64_im_lane_boundsi to accept an
extra argument and change the first two arguments to size_t type so we
don't get an extra cast there and do the division inside the compiler
itself.

Also we don't want to cause an ICE on any source code so I changed the
assert to be a sorry if either of the two arguments are not integer
constants.

OK?  Bootstrapped and tested on aarch64-linux-gnu with no regressions
and I was able to bootstrap without a modified libcpp.

Thanks,
Andrew Pinski

ChangeLog:
            * config/aarch64/aarch64-builtins.c (aarch64_init_simd_builtins):
            Change the first argument type to size_type_node and add another
            size_type_node.
            (aarch64_simd_expand_builtin): Handle the new argument to
            AARCH64_SIMD_BUILTIN_LANE_CHECK and don't ICE but rather
            print sorry out when the first two arguments are not
            integer constants.
            * config/aarch64/arm_neon.h (__AARCH64_LANE_CHECK):
            Pass the sizeof's directly to __builtin_aarch64_im_lane_boundsi.

testsuite/ChangeLog:
            * c-c++-common/torture/aarch64-vect-lane-1.c: New testcase.