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From: "rguenth at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Subject: [Bug tree-optimization/107647] [12/13 Regression] GCC 12.2.0 may produce FMAs even with -ffp-contract=off
Date: Thu, 17 Nov 2022 13:16:35 +0000 [thread overview]
Message-ID: <bug-107647-4-GU3LT5xtpl@http.gcc.gnu.org/bugzilla/> (raw)
In-Reply-To: <bug-107647-4@http.gcc.gnu.org/bugzilla/>
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=107647
--- Comment #16 from Richard Biener <rguenth at gcc dot gnu.org> ---
(In reply to Alexander Monakov from comment #15)
> I'm confused about the first hunk in the attached patch:
>
> --- a/gcc/tree-vect-slp-patterns.cc
> +++ b/gcc/tree-vect-slp-patterns.cc
> @@ -1035,8 +1035,10 @@ complex_mul_pattern::matches (complex_operation_t op,
> auto_vec<slp_tree> left_op, right_op;
> slp_tree add0 = NULL;
>
> - /* Check if we may be a multiply add. */
> + /* Check if we may be a multiply add. It's only valid to form FMAs
> + with -ffp-contract=fast. */
> if (!mul0
> + && flag_fp_contract_mode != FP_CONTRACT_FAST
> && vect_match_expression_p (l0node[0], PLUS_EXPR))
> {
> auto vals = SLP_TREE_CHILDREN (l0node[0]);
>
>
> Shouldn't it be ' == FP_CONTRACT_FAST' rather than '!='? It seems we are
> checking that a match is found and contracting across statement boundaries
> is allowed.
whoops yes, I'll fix and add a check for the type.
next prev parent reply other threads:[~2022-11-17 13:16 UTC|newest]
Thread overview: 23+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-11-11 16:59 [Bug tree-optimization/107647] New: " bartoldeman at users dot sourceforge.net
2022-11-11 17:05 ` [Bug tree-optimization/107647] " bartoldeman at users dot sourceforge.net
2022-11-11 17:12 ` [Bug tree-optimization/107647] [12/13 Regression] " pinskia at gcc dot gnu.org
2022-11-11 17:22 ` amonakov at gcc dot gnu.org
2022-11-11 17:27 ` pinskia at gcc dot gnu.org
2022-11-11 17:33 ` pinskia at gcc dot gnu.org
2022-11-11 17:41 ` amonakov at gcc dot gnu.org
2022-11-11 17:54 ` pinskia at gcc dot gnu.org
2022-11-14 11:43 ` rguenth at gcc dot gnu.org
2022-11-14 11:49 ` rguenth at gcc dot gnu.org
2022-11-17 8:38 ` rguenth at gcc dot gnu.org
2022-11-17 8:59 ` tnfchris at gcc dot gnu.org
2022-11-17 9:07 ` tnfchris at gcc dot gnu.org
2022-11-17 9:10 ` rguenth at gcc dot gnu.org
2022-11-17 9:15 ` tnfchris at gcc dot gnu.org
2022-11-17 9:21 ` amonakov at gcc dot gnu.org
2022-11-17 13:16 ` rguenth at gcc dot gnu.org [this message]
2022-11-18 7:37 ` cvs-commit at gcc dot gnu.org
2022-11-18 7:48 ` [Bug tree-optimization/107647] [12 " rguenth at gcc dot gnu.org
2022-11-21 9:45 ` tnfchris at gcc dot gnu.org
2022-11-22 7:07 ` rguenth at gcc dot gnu.org
2022-12-12 11:20 ` cvs-commit at gcc dot gnu.org
2022-12-12 11:21 ` rguenth at gcc dot gnu.org
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