https://gcc.gnu.org/bugzilla/show_bug.cgi?id=86833
Bug ID: 86833
Summary: No Warning for uninitilized array unless optimization
on
Product: gcc
Version: unknown
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: c
Assignee: unassigned at gcc dot gnu.org
Reporter: wladislav.artsimovich at iws dot fraunhofer.de
Target Milestone: ---
As asked on stackoverflow.com/questions/51659180,
The following code causes a Segmentation fault:
int main()
{
double array[2]={0, 0};
printf("%f\n", array[999]);
return 0;
}
Compiling with "gcc -Wall -O1" throws:
main.c: In function 'main':
main.c:6:5: warning: 'array[999]' is used uninitialized in this function
[-Wuninitialized]
printf("%f\n", array[999]);
^~~~~~~~~~~~~~~~~~~~~~~~~~
While compiling with "gcc -Wall" or equivalent "gcc -Wall -O0" throws no error
at all.
I got told, that this is typical, because unless O1 is set GCC performs no
checks related to such memory management.
It was also mentioned, that clang throws an error in all cases.
Usually Linters use no Optimization and will miss that.
