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From: "k.even-mendoza at imperial dot ac.uk" <gcc-bugzilla@gcc.gnu.org> To: gcc-bugs@gcc.gnu.org Subject: [Bug c/102606] New: miscompilation of a program with large array in a dead-code Date: Tue, 05 Oct 2021 11:48:57 +0000 [thread overview] Message-ID: <bug-102606-4@http.gcc.gnu.org/bugzilla/> (raw) https://gcc.gnu.org/bugzilla/show_bug.cgi?id=102606 Bug ID: 102606 Summary: miscompilation of a program with large array in a dead-code Product: gcc Version: 12.0 Status: UNCONFIRMED Severity: normal Priority: P3 Component: c Assignee: unassigned at gcc dot gnu.org Reporter: k.even-mendoza at imperial dot ac.uk Target Milestone: --- This program miscompiled with gcc-12 (and also older versions) with -O0: #include "stdio.h" void foo(int *p) { if(0) // Dead-code { int *i[(3500)][(300)]; } } int main() { int i = 1; foo(&i); printf("1\n"); return 0; } the program terminates with Segmentation fault when compiled with -O0 and GCC, but with -O1,O2,O3,Os and clang (all flags), it prints "1" and return 0. I assume the definition of "i" is being pulled up, out side the if(0) block. I used gcc (GCC) 12.0.0 20210811 (experimental).
next reply other threads:[~2021-10-05 11:48 UTC|newest] Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top 2021-10-05 11:48 k.even-mendoza at imperial dot ac.uk [this message] 2021-10-05 11:52 ` [Bug middle-end/102606] large array in a dead-code is not optimized away at -O0 pinskia at gcc dot gnu.org 2021-10-05 12:08 ` rguenth at gcc dot gnu.org 2021-10-05 16:17 ` jakub at gcc dot gnu.org 2021-10-05 18:02 ` k.even-mendoza at imperial dot ac.uk 2021-10-08 20:47 ` pinskia at gcc dot gnu.org
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