On Tue, 23 Jan 2024, Tamar Christina wrote:
> Hi All,
>
> This fixes a bug where vect_create_epilog_for_reduction does not handle the
> case where all exits are early exits. In this case we should do like
> induction
> handling code does and not have a main exit.
>
> Bootstrapped Regtested on x86_64-pc-linux-gnu
> with --enable-checking=release --enable-lto --with-arch=native
> --with-build-config=bootstrap-O3 --enable-checking=yes,rtl,extra.
>
> This shows that some new miscompiles are happening (stage3 is likely
> miscompiled)
> but that's unrelated to this patch and I'll look at it next.
>
> Ok for master?
OK, but can you, as followup, change the name of main_exit_p which
doesn't reflect how it's computed now?
> Thanks,
> Tamar
>
> gcc/ChangeLog:
>
> PR tree-optimization/113364
> * tree-vect-loop.cc (vect_create_epilog_for_reduction): If all exits all
> early exits then we must reduce from the first offset for all of them.
>
> gcc/testsuite/ChangeLog:
>
> PR tree-optimization/113364
> * gcc.dg/vect/vect-early-break_107-pr113364.c: New test.
>
> --- inline copy of patch --
> diff --git a/gcc/testsuite/gcc.dg/vect/vect-early-break_107-pr113364.c
> b/gcc/testsuite/gcc.dg/vect/vect-early-break_107-pr113364.c
> new file mode 100644
> index
> 0000000000000000000000000000000000000000..f489265dbfe5eb8fe302dcc34901abaf6e6d5c14
> --- /dev/null
> +++ b/gcc/testsuite/gcc.dg/vect/vect-early-break_107-pr113364.c
> @@ -0,0 +1,22 @@
> +/* { dg-do compile } */
> +/* { dg-add-options vect_early_break } */
> +/* { dg-require-effective-target vect_early_break } */
> +/* { dg-require-effective-target vect_int } */
> +/* { dg-additional-options "-w" } */
> +
> +typedef const unsigned char *It;
> +It DecodeSLEB128(It begin, It end, int *v) {
> + int value = 0;
> + unsigned shift = 0;
> + unsigned char byte;
> + do
> + {
> + if (begin == end)
> + return begin;
> + byte = *(begin++);
> + int slice = byte & 0x7f;
> + value |= slice << shift;
> + } while (byte >= 128);
> + *v = value;
> + return begin;
> +}
> diff --git a/gcc/tree-vect-loop.cc b/gcc/tree-vect-loop.cc
> index
> fe631252dc2258e8ea42179b4ba068a480be9e38..4da1421c8f09746ef4b293573e4f861b642349e1
> 100644
> --- a/gcc/tree-vect-loop.cc
> +++ b/gcc/tree-vect-loop.cc
> @@ -5982,7 +5982,8 @@ vect_create_epilog_for_reduction (loop_vec_info
> loop_vinfo,
> loop-closed PHI of the inner loop which we remember as
> def for the reduction PHI generation. */
> bool double_reduc = false;
> - bool main_exit_p = LOOP_VINFO_IV_EXIT (loop_vinfo) == loop_exit;
> + bool main_exit_p = LOOP_VINFO_IV_EXIT (loop_vinfo) == loop_exit
> + && !LOOP_VINFO_EARLY_BREAKS_VECT_PEELED (loop_vinfo);
> stmt_vec_info rdef_info = stmt_info;
> if (STMT_VINFO_DEF_TYPE (stmt_info) == vect_double_reduction_def)
> {
>
>
>
>
>
--
Richard Biener <rguent...@suse.de>
SUSE Software Solutions Germany GmbH,
Frankenstrasse 146, 90461 Nuernberg, Germany;
GF: Ivo Totev, Andrew McDonald, Werner Knoblich; (HRB 36809, AG Nuernberg)
