From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: by sourceware.org (Postfix, from userid 48) id BEF183857804; Fri, 15 Jan 2021 01:42:03 +0000 (GMT) DKIM-Filter: OpenDKIM Filter v2.11.0 sourceware.org BEF183857804 From: "vsevolod.livinskij at frtk dot ru" To: gcc-bugs@gcc.gnu.org Subject: [Bug tree-optimization/98694] New: GCC produces incorrect code for loops with -O3 for skylake-avx512 and icelake-server Date: Fri, 15 Jan 2021 01:42:03 +0000 X-Bugzilla-Reason: CC X-Bugzilla-Type: new X-Bugzilla-Watch-Reason: None X-Bugzilla-Product: gcc X-Bugzilla-Component: tree-optimization X-Bugzilla-Version: 11.0 X-Bugzilla-Keywords: X-Bugzilla-Severity: normal X-Bugzilla-Who: vsevolod.livinskij at frtk dot ru X-Bugzilla-Status: UNCONFIRMED X-Bugzilla-Resolution: X-Bugzilla-Priority: P3 X-Bugzilla-Assigned-To: unassigned at gcc dot gnu.org X-Bugzilla-Target-Milestone: --- X-Bugzilla-Flags: X-Bugzilla-Changed-Fields: bug_id short_desc product version bug_status bug_severity priority component assigned_to reporter target_milestone Message-ID: 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 X-BeenThere: gcc-bugs@gcc.gnu.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Gcc-bugs mailing list List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Fri, 15 Jan 2021 01:42:03 -0000 https://gcc.gnu.org/bugzilla/show_bug.cgi?id=3D98694 Bug ID: 98694 Summary: GCC produces incorrect code for loops with -O3 for skylake-avx512 and icelake-server Product: gcc Version: 11.0 Status: UNCONFIRMED Severity: normal Priority: P3 Component: tree-optimization Assignee: unassigned at gcc dot gnu.org Reporter: vsevolod.livinskij at frtk dot ru Target Milestone: --- The reproducer is a bit big, but I was not able to reduce it further. Reproducer: // func.cpp #include extern short var_1, var_29, var_89; extern unsigned var_2, var_11; extern bool var_4; extern long var_6; extern char var_7; extern int var_8, var_10; extern short arr_206[10][14][13][21][14] __attribute__((aligned)); extern int arr_257[]; long f(long l) { return 0 > l ? 0 : l; } void test() { var_11 =3D var_6; for (char a =3D 0; a < (char)var_2; a =3D 6) for (int b =3D 0; b < var_2; b =3D ~0) for (int c =3D 0; c < 2; c =3D var_1) for (bool d =3D 0; d < var_4; d =3D 1) var_29 =3D f(~var_6); for (short e =3D 0; e < short(var_6); e =3D var_6) { for (; 0 < (int)var_6;) ; for (char g =3D 0; g < 4; g++) for (; std::min(var_7 / 405077347810ULL, (unsigned long long)9); var_7 +=3D 2) for (char h =3D 0; h < (char)var_8; h +=3D 4) for (short i =3D 0; i < (var_4 && var_6) + 13; i++) { arr_206[0][g][0][h][i] =3D var_6; var_89 =3D std::min(var_4 ?: 709U, (unsigned)var_4); } for (short j =3D 0; j < var_2; j +=3D 4) for (int k =3D 0; k < 5U; k =3D var_10) arr_257[k] =3D var_6; } } // driver.cpp #include short var_1 =3D (short)7531; unsigned int var_2 =3D 187158918U; bool var_4 =3D (bool)1; unsigned long long int var_6 =3D 10263287916162477044ULL; signed char var_7 =3D 0; long long int var_8 =3D 21; unsigned int var_10 =3D 3309705747U; unsigned int var_11 =3D 222967114U; short var_29 =3D (short)-22723; short var_89 =3D (short)-19017; short arr_206 [10] [14] [13] [21] [14] __attribute__((aligned)); int arr_257 [5]; void test(); int main() { test(); for (size_t i_0 =3D 0; i_0 < 5; ++i_0) printf("%d ", arr_257 [i_0]); printf("\n"); } Error: >$ g++ -march=3Dskylake-avx512 func.cpp driver.cpp -O2 && sde -skx -- ./a.o= ut=20 -2039714828 0 0 0 0=20 >$ g++ -march=3Dskylake-avx512 func.cpp driver.cpp -O3 && sde -skx -- ./a.o= ut=20 27636 0 0 0 0 gcc version 11.0.0 20210113 (8fc183ccd0628465205b8a88c29ab69bfe74a08a)=