* cse.c (fold_rtx): Update comments for (const (minus (label) (label)))
        case.
        (cse_insn): Avoid creating a bogus REG_EQUAL note for
        (const (minus (label) (label)))
        (record_jump_cond): Fix mismatched paren in comment.
Fixes powerpc label-label problem.
Bootstraps on the x86.

Co-Authored-By: Jeffrey A Law <law@cygnus.com>

From-SVN: r25527