On Fri, Mar 09, 2018 at 02:23:13PM +0100, Richard Biener wrote:
>
> With -Os we inhibit most loop header copying which in turn will disable
> any vectorization attempt either via -fopenmp or via -ftree-vectorize.
>
> The following makes sure the aggressive gate in
> should_duplicate_loop_header_p is not applied for force-vectorize loops.
> There's still PARAM_MAX_LOOP_HEADER_INSNS limiting growth.
>
> This reportedly makes -fopenmp -Os vectorize loops properly.
>
> Bootstrap / regtest running on x86_64-unknown-linux-gnu.
>
> Is this OK for trunk (and branches?) or do we want sth different
> in the end?
LGTM.
> 2018-03-09 Richard Biener <rguent...@suse.de>
>
> PR tree-optimization/84777
> * tree-ssa-loop-ch.c (should_duplicate_loop_header_p): For
> force-vectorize loops ignore whether we are optimizing for size.
>
> Index: gcc/tree-ssa-loop-ch.c
> ===================================================================
> --- gcc/tree-ssa-loop-ch.c (revision 258380)
> +++ gcc/tree-ssa-loop-ch.c (working copy)
> @@ -57,7 +57,8 @@ should_duplicate_loop_header_p (basic_bl
> be true, since quite often it is possible to verify that the condition
> is
> satisfied in the first iteration and therefore to eliminate it. Jump
> threading handles these cases now. */
> - if (optimize_loop_for_size_p (loop))
> + if (optimize_loop_for_size_p (loop)
> + && !loop->force_vectorize)
> {
> if (dump_file && (dump_flags & TDF_DETAILS))
> fprintf (dump_file,
Jakub
