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From: "cyp561 at gmail dot com" <gcc-bugzilla@gcc.gnu.org> To: gcc-bugs@gcc.gnu.org Subject: [Bug c++/51392] New: Wrong code with -Os when __attribute__((__const__)) function returns structure Date: Sat, 03 Dec 2011 10:09:00 -0000 [thread overview] Message-ID: <bug-51392-4@http.gcc.gnu.org/bugzilla/> (raw) http://gcc.gnu.org/bugzilla/show_bug.cgi?id=51392 Bug #: 51392 Summary: Wrong code with -Os when __attribute__((__const__)) function returns structure Classification: Unclassified Product: gcc Version: 4.5.3 Status: UNCONFIRMED Severity: normal Priority: P3 Component: c++ AssignedTo: unassigned@gcc.gnu.org ReportedBy: cyp561@gmail.com Target: x86_64-pc-linux-gnu Build: gcc version 4.5.3 (Gentoo 4.5.3-r1 p1.0, pie-0.4.5) Fails with -Os, works with -O2: 4.5.3 Works always: 4.1.2 4.2.4 4.3.6 4.4.6 Fails always: 3.4.6 Only fails if the copy constructor is manually defined. Works with __attribute__((__pure__)) instead of __attribute__((__const__)). Still fails with printf and #include <stdio.h> removed. Maybe it's somehow illegal with __attribute__((__const__)) to return a structure with a manually defined copy constructor? Testcase, reduced as much as I could: /* $ g++ -O2 -o error error.cpp $ ./error (-11 1 4) $ g++ -Os -o error error.cpp $ ./error (1790250 1127603896 -1465067344) Aborted $ ./error (1801140 -1464045896 574146144) Aborted */ extern "C" void abort(); struct Vector3f { Vector3f() {} Vector3f(int x, int y, int z) : x(x), y(y), z(z) {} Vector3f(Vector3f const &v) : x(v.x), y(v.y), z(v.z) {} // Essential int x, y, z; }; __attribute__((__const__)) Vector3f pie_SurfaceNormal3fv(Vector3f a, Vector3f b) { return Vector3f(a.y*b.z - a.z*b.y, a.z*b.x - a.x*b.z, a.x*b.y - a.y*b.x); } void normalsOnTile(Vector3f *normals) { Vector3f b(3, 5, 7); Vector3f c(4, 8, 9); *normals = pie_SurfaceNormal3fv(b, c); } #include <stdio.h> int main() { Vector3f normals; normalsOnTile(&normals); printf("(%d %d %d)\n", normals.x, normals.y, normals.z); if (normals.x != -11) abort(); }
next reply other threads:[~2011-12-03 10:09 UTC|newest] Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top 2011-12-03 10:09 cyp561 at gmail dot com [this message] 2011-12-03 16:27 ` [Bug c++/51392] " cybersphinx.gcc at dispostable dot com 2011-12-04 14:04 ` mikpe at it dot uu.se 2011-12-04 15:51 ` rguenth at gcc dot gnu.org
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