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From: "jakub at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org> To: gcc-bugs@gcc.gnu.org Subject: [Bug tree-optimization/110755] [13/14 Regression] Wrong optimization of fabs on ppc64el at -O1 Date: Fri, 21 Jul 2023 08:11:24 +0000 [thread overview] Message-ID: <bug-110755-4-VmRgZwIELu@http.gcc.gnu.org/bugzilla/> (raw) In-Reply-To: <bug-110755-4@http.gcc.gnu.org/bugzilla/> https://gcc.gnu.org/bugzilla/show_bug.cgi?id=110755 --- Comment #5 from Jakub Jelinek <jakub at gcc dot gnu.org> --- A big hammer solution might be to treat flag_rounding_math in frange::set the same as !HONOR_SIGNED_ZEROS, i.e. always extend [0, x] ranges to [-0, x] and [y, -0] to [y, 0] because we don't know what the rounding will do: - else if (!HONOR_SIGNED_ZEROS (m_type)) + else if (!HONOR_SIGNED_ZEROS (m_type) || flag_rounding_math) { if (real_iszero (&m_max, 1)) m_max.sign = 0; if (real_iszero (&m_min, 0)) m_min.sign = 1; } Though, such a change would affect even say operator_abs handling where we even for flag_rounding_math are guaranteed the sign will be positive (unless -fno-signed-zeros, in that case it is right we don't assume anything). Or do it in range_operator::fold_range? Or some other spot? Generally, operations like neg, abs, comparisons should be fine, but +-*/ at least in the fold_range direction probably need to do that.
next prev parent reply other threads:[~2023-07-21 8:11 UTC|newest] Thread overview: 17+ messages / expand[flat|nested] mbox.gz Atom feed top 2023-07-20 20:18 [Bug target/110755] New: " aurelien at aurel32 dot net 2023-07-20 20:25 ` [Bug target/110755] " pinskia at gcc dot gnu.org 2023-07-20 20:28 ` aurelien at aurel32 dot net 2023-07-20 20:31 ` [Bug tree-optimization/110755] [13/14 Regression] " pinskia at gcc dot gnu.org 2023-07-21 6:56 ` rguenth at gcc dot gnu.org 2023-07-21 8:11 ` jakub at gcc dot gnu.org [this message] 2023-07-21 8:38 ` jakub at gcc dot gnu.org 2023-07-22 20:20 ` aurelien at aurel32 dot net 2023-07-24 7:12 ` jakub at gcc dot gnu.org 2023-07-24 7:47 ` jakub at gcc dot gnu.org 2023-07-24 18:31 ` aurelien at aurel32 dot net 2023-07-26 8:52 ` cvs-commit at gcc dot gnu.org 2023-07-26 10:00 ` [Bug tree-optimization/110755] [13 " jakub at gcc dot gnu.org 2023-07-27 9:27 ` rguenth at gcc dot gnu.org 2023-07-27 17:53 ` cvs-commit at gcc dot gnu.org 2023-08-30 22:21 ` jakub at gcc dot gnu.org 2023-11-06 2:38 ` hp at gcc dot gnu.org
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