From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: by sourceware.org (Postfix, from userid 48) id 6CCC13875DDA; Tue, 17 Oct 2023 11:37:29 +0000 (GMT) DKIM-Filter: OpenDKIM Filter v2.11.0 sourceware.org 6CCC13875DDA DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gcc.gnu.org; s=default; t=1697542649; bh=SvTQiREouTODN+nIZKJiCkedBsBmbv0+yT2O2rRGhhU=; h=From:To:Subject:Date:In-Reply-To:References:From; b=DI43wW+QCoa2KcaxiLkrgxa+oQ0UNjRdaEj/aTsFxEUetf34u2ZjwDRLv8uUXE0TC chVTdAhfxnzGW4F483Mhrgvew3L5sdaBHtlDzVcYZAc8/H1XJ7VyfVZ6sza5F0wHJR 4cm5mYTJU8QVmN+A/Gy2q7p8Cc/HsBM2PBsGVahg= From: "jakub at gcc dot gnu.org" To: gcc-bugs@gcc.gnu.org Subject: [Bug middle-end/111845] [14 regression] ICE when building pycryptodome Date: Tue, 17 Oct 2023 11:37:27 +0000 X-Bugzilla-Reason: CC X-Bugzilla-Type: changed X-Bugzilla-Watch-Reason: None X-Bugzilla-Product: gcc X-Bugzilla-Component: middle-end X-Bugzilla-Version: 14.0 X-Bugzilla-Keywords: ice-on-valid-code X-Bugzilla-Severity: normal X-Bugzilla-Who: jakub at gcc dot gnu.org X-Bugzilla-Status: NEW X-Bugzilla-Resolution: X-Bugzilla-Priority: P1 X-Bugzilla-Assigned-To: unassigned at gcc dot gnu.org X-Bugzilla-Target-Milestone: 14.0 X-Bugzilla-Flags: X-Bugzilla-Changed-Fields: Message-ID: In-Reply-To: References: Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable X-Bugzilla-URL: http://gcc.gnu.org/bugzilla/ Auto-Submitted: auto-generated MIME-Version: 1.0 List-Id: https://gcc.gnu.org/bugzilla/show_bug.cgi?id=3D111845 --- Comment #6 from Jakub Jelinek --- Same with renamed vars, so that the long variable names don't make it unreadable: int a, b; unsigned int c, d, e; void foo (int x) { b +=3D d; c +=3D b < d; b +=3D e =3D a < x; c +=3D b; c +=3D b < e; } I believe the above is equivalent to: e =3D a < x; unsigned c1; b =3D __builtin_addc (b, d, e, &c1); c =3D __builtin_addc (c, b, c1, &c1); i.e. b is set to b + d + e where e is in [0, 1] range and c is set to c + b= + carry-out from the b + d + e additions. match_uaddc_usubc is called on the _17 =3D _30 + _31; addition in: b.0_1 =3D b; b.1_2 =3D (unsigned int) b.0_1; d.2_3 =3D d; _8 =3D .ADD_OVERFLOW (b.1_2, d.2_3); _4 =3D REALPART_EXPR <_8>; _14 =3D IMAGPART_EXPR <_8>; _5 =3D _14 !=3D 0; _6 =3D (unsigned int) _5; c.6_7 =3D c; _31 =3D _6 + c.6_7; a.7_9 =3D a; _10 =3D a.7_9 < x_19(D); _11 =3D (unsigned int) _10; e =3D _11; _29 =3D .ADD_OVERFLOW (_4, _11); _12 =3D REALPART_EXPR <_29>; _28 =3D IMAGPART_EXPR <_29>; _13 =3D (int) _12; b =3D _13; _15 =3D _28 !=3D 0; _16 =3D (unsigned int) _15; _30 =3D _12 + _16; _17 =3D _30 + _31; c =3D _17; return; and changes it: @@ -12,14 +12,14 @@ a.7_9 =3D a; _10 =3D a.7_9 < x_19(D); _11 =3D (unsigned int) _10; e =3D _11; +_27 =3D .UADDC (b.1_2, d.2_3, _11); _29 =3D .ADD_OVERFLOW (_4, _11); -_12 =3D REALPART_EXPR <_29>; -_28 =3D IMAGPART_EXPR <_29>; +_12 =3D REALPART_EXPR <_27>; _13 =3D (int) _12; b =3D _13; -_15 =3D _28 !=3D 0; -_16 =3D (unsigned int) _15; _30 =3D _12 + _16; -_17 =3D _30 + _31; +_26 =3D IMAGPART_EXPR <_27>; +_25 =3D .UADDC (c.6_7, _12, _26); +_17 =3D REALPART_EXPR <_25>; c =3D _17; return; That again looks correct to me, except that the dead _30 =3D _12 + _16 stat= ement should have been removed as well but wasn't. The bb contains still other d= ead statements but the _30 =3D _12 + _16; is the only problematic one, as it refers to rel= eased SSA_NAME. After a fast DCE I think the bb would turn into: b.0_1 =3D b; b.1_2 =3D (unsigned int) b.0_1; d.2_3 =3D d; c.6_7 =3D c; a.7_9 =3D a; _10 =3D a.7_9 < x_19(D); _11 =3D (unsigned int) _10; e =3D _11; _27 =3D .UADDC (b.1_2, d.2_3, _11); _12 =3D REALPART_EXPR <_27>; _13 =3D (int) _12; b =3D _13; _26 =3D IMAGPART_EXPR <_27>; _25 =3D .UADDC (c.6_7, _12, _26); _17 =3D REALPART_EXPR <_25>; c =3D _17; return;=