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From: "rguenth at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org> To: gcc-bugs@gcc.gnu.org Subject: [Bug middle-end/112344] [14 Regression] Wrong code at -O2 on x86_64-pc-linux-gnu Date: Wed, 22 Nov 2023 10:06:28 +0000 [thread overview] Message-ID: <bug-112344-4-1JwTRJSIO1@http.gcc.gnu.org/bugzilla/> (raw) In-Reply-To: <bug-112344-4@http.gcc.gnu.org/bugzilla/> https://gcc.gnu.org/bugzilla/show_bug.cgi?id=112344 --- Comment #9 from Richard Biener <rguenth at gcc dot gnu.org> --- In particular the final jump is miscalculated somehow, possibly path-ranger mishandles the situation. For the loop header we thread through we first clear dependent ranges (good) but then do compute_ranges_in_phis (weird, we know the incoming edge?), doing Value_Range r (TREE_TYPE (name)); if (range_defined_in_block (r, name, bb)) m_cache.set_range (name, r); where this ends up calling ssa_range_in_phi, resulting in [irange] int [1, 1]$69 = void Hmm, so we have _41 : [irange] int [1073741833, 1073741833] _42 : [irange] int [+INF, +INF] and <bb 4> [local count: 105119324]: _37 = e_1 + 2; _38 = (unsigned int) e_1; _39 = 19 - _38; _40 = _39 / 2; _41 = (int) _40; _42 = _41 * 2; so it's the e_9 replacement that is wrong. This is chrec_apply, applying the unsigned number of iterations (19 - (unsigned int) e_31) / 2 to the signed chrec {e_31 + 2, +, 2}_2. This isn't without overflow when computing the overall increment from INT_MIN to 19 since that positive number cannot be represented in a signed integer type.
next prev parent reply other threads:[~2023-11-22 10:06 UTC|newest] Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top 2023-11-02 6:30 [Bug middle-end/112344] New: " jwzeng at nuaa dot edu.cn 2023-11-02 6:41 ` [Bug middle-end/112344] " pinskia at gcc dot gnu.org 2023-11-02 6:42 ` pinskia at gcc dot gnu.org 2023-11-02 6:47 ` jwzeng at nuaa dot edu.cn 2023-11-02 6:49 ` pinskia at gcc dot gnu.org 2023-11-02 10:06 ` rguenth at gcc dot gnu.org 2023-11-21 19:22 ` jakub at gcc dot gnu.org 2023-11-21 19:23 ` jakub at gcc dot gnu.org 2023-11-22 7:43 ` rguenth at gcc dot gnu.org 2023-11-22 9:10 ` rguenth at gcc dot gnu.org 2023-11-22 10:06 ` rguenth at gcc dot gnu.org [this message] 2023-11-22 14:40 ` cvs-commit at gcc dot gnu.org 2023-11-22 14:41 ` rguenth at gcc dot gnu.org 2023-11-24 7:50 ` cvs-commit at gcc dot gnu.org 2024-02-18 10:07 ` cvs-commit at gcc dot gnu.org
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