public inbox for gcc-bugs@sourceware.org
help / color / mirror / Atom feed
* [Bug c/14947] New: Optimization leads to SegV for large locals on MAC Power PC
@ 2004-04-13 22:12 fsmith at mathworks dot com
2004-04-13 22:45 ` [Bug optimization/14947] " pinskia at gcc dot gnu dot org
0 siblings, 1 reply; 2+ messages in thread
From: fsmith at mathworks dot com @ 2004-04-13 22:12 UTC (permalink / raw)
To: gcc-bugs
/*
This program segvs with gcc -O, but not with plain gcc.
The differences between the crashing version with Sz1 and the non-crashing
version with SZ2 are;
$ diff mactest.s mactest_segv.
25c25
< li r4,8172
---
> li r4,8173
59c59
< ori r0,r0,32752
---
> ori r0,r0,32736
65,69d64
< xoris r0,r30,0x8000
< stw r0,32756(r1)
< lis r0,0x4330
< stw r0,32752(r1)
< lfd f13,32752(r1)
71a67,72
> lis r0,0x4330
> add r9,r9,r1
> xoris r2,r30,0x8000
> stw r2,4(r9)
> stw r0,0(r9)
> lfd f13,0(r9)
Inspecting this code in the broader context the problem appears to be that
r9 is used without being initialized
gcc -v returns:
Reading specs from /usr/libexec/gcc/darwin/ppc/3.3/specs
Thread model: posix
gcc version 3.3 20030304 (Apple Computer, Inc. build 1495)
*/
#include<stdio.h>
#define SZ1 8192-19
#define SZ2 8192-20
/* Crashes with SZ1 but not with SZ2 or smaller sizes. */
#define SZ SZ1
void prn(int j, double k) /* double is required here. */
{
printf("SZ=%d j=%d, k=%g\n",SZ,j,k);
fflush(stdout);
}
int main(void)
{
int j=0;
int A[SZ];
do { /* loop required. */
prn(j,/* implicit cast here. */ j);
} while(j);
return 0;
}
--
Summary: Optimization leads to SegV for large locals on MAC Power
PC
Product: gcc
Version: 3.3
Status: UNCONFIRMED
Severity: normal
Priority: P2
Component: c
AssignedTo: unassigned at gcc dot gnu dot org
ReportedBy: fsmith at mathworks dot com
CC: gcc-bugs at gcc dot gnu dot org
GCC build triplet: gcc version 3.3 20030304 (Apple Computer, Inc. build
1495)
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=14947
^ permalink raw reply [flat|nested] 2+ messages in thread
end of thread, other threads:[~2004-04-13 22:00 UTC | newest]
Thread overview: 2+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2004-04-13 22:12 [Bug c/14947] New: Optimization leads to SegV for large locals on MAC Power PC fsmith at mathworks dot com
2004-04-13 22:45 ` [Bug optimization/14947] " pinskia at gcc dot gnu dot org
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for read-only IMAP folder(s) and NNTP newsgroup(s).