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From: "jakub at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org> To: gcc-bugs@gcc.gnu.org Subject: [Bug target/107131] [11/12/13 Regression] wrong code with -Os -fno-ipa-vrp -fno-tree-bit-ccp Date: Fri, 13 Jan 2023 16:27:23 +0000 [thread overview] Message-ID: <bug-107131-4-acy92QPQD1@http.gcc.gnu.org/bugzilla/> (raw) In-Reply-To: <bug-107131-4@http.gcc.gnu.org/bugzilla/> https://gcc.gnu.org/bugzilla/show_bug.cgi?id=107131 Jakub Jelinek <jakub at gcc dot gnu.org> changed: What |Removed |Added ---------------------------------------------------------------------------- CC| |hjl.tools at gmail dot com, | |uros at gcc dot gnu.org --- Comment #8 from Jakub Jelinek <jakub at gcc dot gnu.org> --- I think the problem happens during combine. Parts of the vector code related to: V b = (V) { } >= o; V c = b <= (V)(b >= (V) { 0, 0, 0, 0, 0, 0x90DF0BE3990AC871ULL }); - in particular the scalar c[5] computation, i.e. unsigned long long b = 0 >= o ? -1ULL : 0ULL; unsigned long long c = b <= (b >= 0x90DF0BE3990AC871ULL ? -1ULL : 0ULL) ? -1ULL : 0ULL; evaluates to 0 rather than -1 that it should when o is 0. This boils down to: __attribute__((noipa)) unsigned long long foo (unsigned char o) { unsigned long long t1 = -(long long) (o == 0); unsigned long long t2 = -(long long) (t1 > 10439075533421201520ULL); unsigned long long t3 = -(long long) (t1 <= t2); return t3; } int main () { if (foo (0) != -1ULL) __builtin_abort (); return 0; } at -O2 or -Os, which was miscompiled starting with r12-303-g86403f4e6e5f7216 and got fixed with r13-3530-g0e36a9c6915c713d30. No idea why this is marked as 11 regression though... So, do we need to backport PR107172 change to 12 branch?
next prev parent reply other threads:[~2023-01-13 16:27 UTC|newest] Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top 2022-10-03 13:37 [Bug target/107131] New: " zsojka at seznam dot cz 2022-10-03 14:48 ` [Bug target/107131] [11/12 Regression] " marxin at gcc dot gnu.org 2022-10-03 19:34 ` pinskia at gcc dot gnu.org 2022-10-03 19:40 ` pinskia at gcc dot gnu.org 2022-10-06 7:12 ` [Bug target/107131] [11/12/13 " rguenth at gcc dot gnu.org 2022-10-18 8:38 ` rguenth at gcc dot gnu.org 2022-11-18 12:52 ` jakub at gcc dot gnu.org 2023-01-13 10:15 ` cvs-commit at gcc dot gnu.org 2023-01-13 14:01 ` jakub at gcc dot gnu.org 2023-01-13 16:27 ` jakub at gcc dot gnu.org [this message] 2023-01-13 16:39 ` cvs-commit at gcc dot gnu.org 2023-01-13 16:42 ` [Bug target/107131] [11/12 " jakub at gcc dot gnu.org 2023-04-27 12:02 ` rguenth at gcc dot gnu.org 2023-04-27 12:03 ` rguenth at gcc dot gnu.org 2023-05-29 10:07 ` jakub at gcc dot gnu.org
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