Committed, thanks Richard.
Pan
-----Original Message-----
From: Gcc-patches <gcc-patches-bounces+pan2.li=intel....@gcc.gnu.org> On Behalf
Of Richard Biener via Gcc-patches
Sent: Thursday, July 6, 2023 3:09 PM
To: Ju-Zhe Zhong <juzhe.zh...@rivai.ai>
Cc: gcc-patches@gcc.gnu.org; richard.sandif...@arm.com
Subject: Re: [PATCH V2] VECT: Fix ICE of variable stride on strieded load/store
with SELECT_VL loop control.
On Thu, 6 Jul 2023, juzhe.zh...@rivai.ai wrote:
> From: Ju-Zhe Zhong <juzhe.zh...@rivai.ai>
>
> Hi, Richi.
>
> Sorry for making mistake on LEN_MASK_GATHER_LOAD/LEN_MASK_SCATTER_STORE
> with SELECT_VL loop control.
OK.
> Consider this following case:
> #define TEST_LOOP(DATA_TYPE, BITS)
> \
> void __attribute__ ((noinline, noclone))
> \
> f_##DATA_TYPE##_##BITS (DATA_TYPE *restrict dest, DATA_TYPE *restrict src,
> \
> INDEX##BITS stride, INDEX##BITS n) \
> {
> \
> for (INDEX##BITS i = 0; i < n; ++i)
> \
> dest[i] += src[i * stride];
> \
> }
>
> When "stride" is a constant, current flow works fine.
> However, when "stride" is a variable. It causes an ICE:
> # vectp_src.67_85 = PHI <vectp_src.67_86(6), src_21(D)(12)>
> ...
> _96 = .SELECT_VL (ivtmp_94, 4);
> ...
> ivtmp_78 = ((sizetype) _39 * (sizetype) _96) * 4;
> vect__11.69_87 = .LEN_MASK_GATHER_LOAD (vectp_src.67_85, _84, 4, { 0, 0, 0, 0
> }, { -1, -1, -1, -1 }, _96, 0);
> ...
> vectp_src.67_86 = vectp_src.67_85 + ivtmp_78;
>
> Becase the IR: ivtmp_78 = ((sizetype) _39 * (sizetype) _96) * 4;
>
> Instead, I split the IR into:
>
> step_stride = _39
> step = step_stride * 4
> ivtmp_78 = step * _96
>
> Thanks.
>
> gcc/ChangeLog:
>
> * tree-vect-stmts.cc (vect_get_strided_load_store_ops): Fix ICE.
>
> ---
> gcc/tree-vect-stmts.cc | 6 ++----
> 1 file changed, 2 insertions(+), 4 deletions(-)
>
> diff --git a/gcc/tree-vect-stmts.cc b/gcc/tree-vect-stmts.cc
> index c10a4be60eb..10e71178ce7 100644
> --- a/gcc/tree-vect-stmts.cc
> +++ b/gcc/tree-vect-stmts.cc
> @@ -3176,10 +3176,8 @@ vect_get_strided_load_store_ops (stmt_vec_info
> stmt_info,
> = fold_build2 (MULT_EXPR, sizetype,
> fold_convert (sizetype, unshare_expr (DR_STEP (dr))),
> loop_len);
> - tree bump = make_temp_ssa_name (sizetype, NULL, "ivtmp");
> - gassign *assign = gimple_build_assign (bump, tmp);
> - gsi_insert_before (gsi, assign, GSI_SAME_STMT);
> - *dataref_bump = bump;
> + *dataref_bump = force_gimple_operand_gsi (gsi, tmp, true, NULL_TREE,
> true,
> + GSI_SAME_STMT);
> }
> else
> {
>
--
Richard Biener <rguent...@suse.de>
SUSE Software Solutions Germany GmbH, Frankenstrasse 146, 90461 Nuernberg,
Germany; GF: Ivo Totev, Andrew Myers, Andrew McDonald, Boudien Moerman;
HRB 36809 (AG Nuernberg)
