improve sloc assignment on bind_expr entry/exit code

2014-06-18  Olivier Hainque <hainque@adacore.com>

        improve sloc assignment on bind_expr entry/exit code

        gcc/
        * tree-core.h (tree_block): Add an "end_locus" field, allowing
        memorization of the end of block source location.
        * tree.h (BLOCK_SOURCE_END_LOCATION): New accessor.
        * gimplify.c (gimplify_bind_expr): Propagate the block start and
        end source location info we have on the block entry/exit code we
        generate.

        testsuite/
        * gnat.dg/blocklocs.adb: New test.

From-SVN: r211773