https://gcc.gnu.org/bugzilla/show_bug.cgi?id=65958
Bug ID: 65958
Summary: -fstack-check breaks __builtin(alloca)
Product: gcc
Version: 4.9.2
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: c
Assignee: unassigned at gcc dot gnu.org
Reporter: felix.janda at posteo dot de
Target Milestone: ---
Target: arm
On arm, gcc-4.9.2 compiles the following snippet to a program which
returns 1 instead of 0 when the option -fstack-check is given.
int main(void)
{
char *p;
if(1) {
char i[48];
p = __builtin_alloca(8);
p[0] = 1;
}
if(1) {
char i[48], j[64];
j[48] = 0;
}
return !p[0];
}
I could reproduce the behavior already with gcc-4.7.1.
The issue causes miscompilation of bash's lib/glob/glob.c. See:
https://bugs.gentoo.org/show_bug.cgi?id=518598
