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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/113210] [14 Regression] ICE: tree check: expected integer_cst, have cond_expr in get_len, at tree.h:6481 Date: Fri, 05 Jan 2024 16:09:49 +0000 [thread overview] Message-ID: <bug-113210-4-QfJ8bPd11J@http.gcc.gnu.org/bugzilla/> (raw) In-Reply-To: <bug-113210-4@http.gcc.gnu.org/bugzilla/> https://gcc.gnu.org/bugzilla/show_bug.cgi?id=113210 --- Comment #7 from Jakub Jelinek <jakub at gcc dot gnu.org> --- Or maybe just a bug in the PLUS_EXPR folding? The code sets NITERSM1 to (short unsigned int) (a.0_1 + 255) + 1 > 256 ? ~(short unsigned int) (a.0_1 + 255) : 0 and then fold_build2s PLUS_EXPR of that and 1 and somehow it folds to 1, that doesn't sound right to me. Now, when folding the + 1 addition just with the second operand, i.e. ~(short unsigned int) (a.0_1 + 255) it correctly folds into -(short unsigned int) (a.0_1 + 255) and obviously the second one to 1. There is also the /* (X + 1) > Y ? -X : 1 simplifies to X >= Y ? -X : 1 when X is unsigned, as when X + 1 overflows, X is -1, so -X == 1. */ (simplify (cond (gt (plus @0 integer_onep) @1) (negate @0) integer_onep@2) (if (TYPE_UNSIGNED (type)) (cond (ge @0 @1) (negate @0) @2))) match.pd rule, but that I'd think should just fold the whole thing to: (short unsigned int) (a.0_1 + 255) >= 256 ? -(short unsigned int) (a.0_1 + 255) : 1 Though, a.0_1 is unsigned char, so (short unsigned int) (a.0_1 + 255) + 1 > 256 is actually never true. So guess the folding is correct.
next prev parent reply other threads:[~2024-01-05 16:09 UTC|newest] Thread overview: 20+ messages / expand[flat|nested] mbox.gz Atom feed top 2024-01-02 23:33 [Bug target/113210] New: [14] RISC-V vector " patrick at rivosinc dot com 2024-01-02 23:38 ` [Bug target/113210] " juzhe.zhong at rivai dot ai 2024-01-02 23:48 ` patrick at rivosinc dot com 2024-01-03 1:33 ` [Bug tree-optimization/113210] [14 Regression] " pinskia at gcc dot gnu.org 2024-01-03 1:34 ` pinskia at gcc dot gnu.org 2024-01-03 1:39 ` pinskia at gcc dot gnu.org 2024-01-03 1:42 ` pinskia at gcc dot gnu.org 2024-01-05 14:37 ` jakub at gcc dot gnu.org 2024-01-05 16:09 ` jakub at gcc dot gnu.org [this message] 2024-01-05 16:21 ` jakub at gcc dot gnu.org 2024-01-08 9:44 ` rguenth at gcc dot gnu.org 2024-01-08 10:02 ` jakub at gcc dot gnu.org 2024-01-08 10:09 ` jakub at gcc dot gnu.org 2024-01-08 10:16 ` rguenth at gcc dot gnu.org 2024-01-08 10:18 ` rguenth at gcc dot gnu.org 2024-01-08 10:25 ` rguenth at gcc dot gnu.org 2024-01-08 15:58 ` jakub at gcc dot gnu.org 2024-01-09 8:36 ` rguenth at gcc dot gnu.org 2024-01-09 9:32 ` cvs-commit at gcc dot gnu.org 2024-01-09 9:32 ` jakub at gcc dot gnu.org
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