On Tue, Dec 22, 2020 at 11:03 PM Alexandre Oliva <ol...@adacore.com> wrote:
>
> On Oct 28, 2020, Richard Biener <richard.guent...@gmail.com> wrote:
>
> >> BTW, any reason why we are not (yet?) using something like:
> >>
> >> #define FOR_EACH_IMM_USE_STMT(STMT, ITER, SSAVAR) \
> >> for (auto_end_imm_use_stmt_traverse auto_end \
> >> ((((STMT) = first_imm_use_stmt (&(ITER), (SSAVAR))), \
> >> &(ITER))); \
> >> !end_imm_use_stmt_p (&(ITER)); \
> >> (void) ((STMT) = next_imm_use_stmt (&(ITER))))
>
> > Just laziness. Or rather last time I remembered this I tried to do it
> > more fancy via range-for but didn't get very far due to the nested
> > iteration ...
>
> Use a dtor to automatically remove ITER from IMM_USE list in
> FOR_EACH_IMM_USE_STMT.
>
> Regstrapped on x86_64-linux-gnu. Ok to install?
Hmm - while the change looks good, doesn't it end up
calling end_imm_use_stmt_tranverse twice for those
uses still calling BREAK_FROM_IMM_USE_STMT?
Thus, please remove uses of BREAK_FROM_IMM_USE_STMT
together with this patch.
Thanks,
Richard.
>
> for gcc/ChangeLog
>
> * ssa-iterators.h (end_imm_use_stmt_traverse): Forward
> declare.
> (auto_end_imm_use_stmt_traverse): New struct.
> (FOR_EACH_IMM_USE_STMT): Use it.
> ---
> gcc/ssa-iterators.h | 29 ++++++++++++++++++++++++-----
> 1 file changed, 24 insertions(+), 5 deletions(-)
>
> diff --git a/gcc/ssa-iterators.h b/gcc/ssa-iterators.h
> index 98724da14522d..817997aa952d4 100644
> --- a/gcc/ssa-iterators.h
> +++ b/gcc/ssa-iterators.h
> @@ -77,16 +77,35 @@ struct imm_use_iterator
> !end_readonly_imm_use_p (&(ITER)); \
> (void) ((DEST) = next_readonly_imm_use (&(ITER))))
>
> -/* Use this iterator to visit each stmt which has a use of SSAVAR. */
> +/* Forward declare for use in the class below. */
> +static inline void end_imm_use_stmt_traverse (imm_use_iterator *);
> +
> +/* arrange to automatically call, upon descruction, end_imm_use_stmt_traverse
> + with a given pointer to imm_use_iterator. */
> +struct auto_end_imm_use_stmt_traverse
> +{
> + imm_use_iterator *imm;
> + auto_end_imm_use_stmt_traverse (imm_use_iterator *imm)
> + : imm (imm) {}
> + ~auto_end_imm_use_stmt_traverse ()
> + { end_imm_use_stmt_traverse (imm); }
> +};
> +
> +/* Use this iterator to visit each stmt which has a use of SSAVAR. The
> + destructor of the auto_end_imm_use_stmt_traverse object deals with
> removing
> + ITER from SSAVAR's IMM_USE list even when leaving the scope early. */
>
> #define FOR_EACH_IMM_USE_STMT(STMT, ITER, SSAVAR) \
> - for ((STMT) = first_imm_use_stmt (&(ITER), (SSAVAR)); \
> + for (struct auto_end_imm_use_stmt_traverse \
> + auto_end_imm_use_stmt_traverse \
> + ((((STMT) = first_imm_use_stmt (&(ITER), (SSAVAR))), \
> + &(ITER))); \
> !end_imm_use_stmt_p (&(ITER)); \
> (void) ((STMT) = next_imm_use_stmt (&(ITER))))
>
> -/* Use this to terminate the FOR_EACH_IMM_USE_STMT loop early. Failure to
> - do so will result in leaving a iterator marker node in the immediate
> - use list, and nothing good will come from that. */
> +/* These used to be needed to exit FOR_EACH_IMM_USE_STMT early, without
> leaving
> + ITER behind in the stmt lists. This is now taken care of automatically,
> but
> + it doesn't hurt to use the macros for documentation purposes. */
> #define BREAK_FROM_IMM_USE_STMT(ITER) \
> { \
> end_imm_use_stmt_traverse (&(ITER)); \
>
> --
> Alexandre Oliva, happy hacker https://FSFLA.org/blogs/lxo/
> Free Software Activist GNU Toolchain Engineer
> Vim, Vi, Voltei pro Emacs -- GNUlius Caesar
