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From: "pinskia at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org> To: gcc-bugs@gcc.gnu.org Subject: [Bug tree-optimization/110557] [13/14 Regression] Wrong code for x86_64-linux-gnu with -O3 -mavx2: vectorized loop mishandles signed bit-fields Date: Wed, 05 Jul 2023 13:15:26 +0000 [thread overview] Message-ID: <bug-110557-4-D7nhb5x5M0@http.gcc.gnu.org/bugzilla/> (raw) In-Reply-To: <bug-110557-4@http.gcc.gnu.org/bugzilla/> https://gcc.gnu.org/bugzilla/show_bug.cgi?id=110557 Andrew Pinski <pinskia at gcc dot gnu.org> changed: What |Removed |Added ---------------------------------------------------------------------------- Status|UNCONFIRMED |NEW Keywords|needs-bisection | Last reconfirmed| |2023-07-05 Ever confirmed|0 |1 Component|target |tree-optimization --- Comment #1 from Andrew Pinski <pinskia at gcc dot gnu.org> --- ifcvt produces correctly the sign extend: <unnamed-signed:56> _ifc__18; _3 = a_14(D) + _2; _ifc__22 = _3->D.3439; _ifc__18 = BIT_FIELD_REF <_ifc__22, 56, 8>; _5 = (long long int) _ifc__18; _6 = _5 * -4; _7 = (long unsigned int) _6; _15 = MAX_EXPR <_7, size_19>; But then the vectorizer misses that: ``` _ifc__18 = BIT_FIELD_REF <_ifc__22, 56, 8>; vect_patt_13.20_76 = vect__ifc__22.19_74 & { 18446744073709551360, 18446744073709551360, 18446744073709551360, 18446744073709551360 }; vect_patt_10.21_77 = vect_patt_13.20_76 >> 8; vect_patt_9.22_78 = VIEW_CONVERT_EXPR<vector(4) long long int>(vect_patt_10.21_77); _5 = (long long int) _ifc__18; vect__6.23_80 = vect_patt_9.22_78 * { -4, -4, -4, -4 }; _6 = _5 * -4; ``` vect_patt_9.22_78 should have been sign extended ... With the C front-end, we get: ``` <unnamed-signed:56> _24; <unnamed-signed:56> _23; _24 = _25->y; _23 = _24 * -4; _22 = (long unsigned int) _23; ``` Which the vectorizer does not understand could be prompted to 64bit and then truncated so it does not vectorize it. r13-3219-g25413fdb2ac24933214123e24ba16502 .
next prev parent reply other threads:[~2023-07-05 13:15 UTC|newest] Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top 2023-07-05 11:10 [Bug target/110557] New: " xry111 at gcc dot gnu.org 2023-07-05 11:11 ` [Bug target/110557] [13/14 Regression] " xry111 at gcc dot gnu.org 2023-07-05 13:15 ` pinskia at gcc dot gnu.org [this message] 2023-07-06 8:17 ` [Bug tree-optimization/110557] " rguenth at gcc dot gnu.org 2023-07-06 10:17 ` avieira at gcc dot gnu.org 2023-07-06 10:21 ` xry111 at gcc dot gnu.org 2023-07-06 11:30 ` xry111 at gcc dot gnu.org 2023-07-06 14:58 ` avieira at gcc dot gnu.org 2023-07-06 16:18 ` xry111 at gcc dot gnu.org 2023-07-06 16:32 ` xry111 at gcc dot gnu.org 2023-07-10 10:36 ` cvs-commit at gcc dot gnu.org 2023-07-10 10:36 ` cvs-commit at gcc dot gnu.org 2023-07-10 10:38 ` xry111 at gcc dot gnu.org 2023-07-11 8:16 ` xry111 at gcc dot gnu.org
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