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From: "jakub at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org> To: gcc-bugs@gcc.gnu.org Subject: [Bug debug/48466] New: [4.4/4.5/4.6 Regression] Wrong variable locations at -O0 on i686 Date: Tue, 05 Apr 2011 18:13:00 -0000 [thread overview] Message-ID: <bug-48466-4@http.gcc.gnu.org/bugzilla/> (raw) http://gcc.gnu.org/bugzilla/show_bug.cgi?id=48466 Summary: [4.4/4.5/4.6 Regression] Wrong variable locations at -O0 on i686 Product: gcc Version: 4.6.0 Status: UNCONFIRMED Severity: normal Priority: P3 Component: debug AssignedTo: unassigned@gcc.gnu.org ReportedBy: jakub@gcc.gnu.org CC: tromey@gcc.gnu.org, hjl@gcc.gnu.org struct S { int a; int *b; }; struct T { struct S a; struct S b; }; struct U { const char *u; }; int n[10]; volatile int v; struct U foo (const char *s) { struct U r; r.u = s; return r; } void bar (struct T *s, int a, int b) { s->a.a = a; s->a.b = &s->a.a; s->b.a = b; s->b.b = &s->b.a; } int main () { struct T t; struct U x = foo ("this is x"); struct S y, z; y.b = n; y.a = 0; bar (&t, 1, 2); v++; z = y; return 0; } compiled with -g -O0 -dA, when you debug this in the debugger, &t is different from the address passed to bar and after the bar call t contains garbage. Most likely this started with http://gcc.gnu.org/viewcvs?root=gcc&view=rev&rev=138438 The t variable has DECL_RTL (mem (plus (frame) (const_int -16)), (frame) is eliminated to bp - 4, but crtl->stack_realign_tried is true (eventhough fde->stack_realign is false) and thus it is encoded as sp - 20 instead of bp - 20. fde->drap_reg is -1. http://gcc.gnu.org/ml/gcc-patches/2008-07/msg02391.html
next reply other threads:[~2011-04-05 18:13 UTC|newest] Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top 2011-04-05 18:13 jakub at gcc dot gnu.org [this message] 2011-04-05 18:13 ` [Bug debug/48466] " jakub at gcc dot gnu.org 2011-04-05 18:55 ` jakub at gcc dot gnu.org 2011-04-05 19:13 ` hjl.tools at gmail dot com 2011-04-06 11:50 ` jakub at gcc dot gnu.org 2011-04-06 20:40 ` jakub at gcc dot gnu.org 2011-04-06 20:42 ` [Bug debug/48466] [4.4/4.5 " jakub at gcc dot gnu.org 2011-04-07 18:31 ` jakub at gcc dot gnu.org 2011-04-07 21:28 ` [Bug debug/48466] [4.4 " jakub at gcc dot gnu.org 2011-04-07 22:21 ` jakub at gcc dot gnu.org
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