Paul Koning <paulkon...@comcast.net> writes:
> @@ -8615,6 +8639,34 @@ so here's a silly made-up example:
> "")
> @end smallexample
>
> +There are two special macros defined for use in the preparation statements:
> +@code{DONE} and @code{FAIL}. Use them with a following semicolon,
> +as a statement.
> +
> +@table @code
> +
> +@findex DONE
> +@item DONE
> +Use the @code{DONE} macro to end RTL generation for the peephole. The
> +only RTL insns generated as replacement for the matched input insn will
> +be those already emitted by explicit calls to @code{emit_insn} within
> +the preparation statements; the replacement pattern is not used.
> +
> +@findex FAIL
> +@item FAIL
> +Make the @code{define_peephole2} fail on this occasion. When a
> @code{define_peephole2}
> +fails, it means that the replacement was not truly available for the
> +particular inputs it was given. In that case, GCC may still apply a
> +later @code{define_peephole2} that also matches the given insn pattern.
> +(Note that this is different from @code{define_split}, where @code{FAIL}
> +prevents the input insn from being split at all.)
> +@end table
> +
> +If the preparation falls through (invokes neither @code{DONE} nor
> +@code{FAIL}), then the @code{define_peephole2} uses the replacement
> +template.
> +
> +
> @noindent
> If we had not added the @code{(match_dup 4)} in the middle of the input
> sequence, it might have been the case that the register we chose at the
Double empty line.
OK otherwise, thanks. (Think this counts as a gen* patch.)
Richard
