https://gcc.gnu.org/bugzilla/show_bug.cgi?id=97425
Bug ID: 97425
Summary: bogus array bounds in -Warray-bounds for a function
array parameter
Product: gcc
Version: 11.0
Status: UNCONFIRMED
Severity: minor
Priority: P3
Component: middle-end
Assignee: unassigned at gcc dot gnu.org
Reporter: msebor at gcc dot gnu.org
Target Milestone: ---
The -Wartray-bounds warnings in the test case below are all expected but the
bounds of the array types referenced in the messages for f3 and and f4 don't
correspond to those in the array parameters.
In f3 the warning should mention ‘int[2][3][4]’ instead and in f4 it should
reference ‘int[1][2][3][4]’.
$ cat z.c && gcc -O2 -S -Wall z.c
void f1 (int a[4])
{
int *p = &a[0];
p[4] = 0;
}
void f2 (int a[3][4])
{
int *p = &a[0][0];
p[3 * 4] = 0;
}
void f3 (int a[2][3][4])
{
int *p = &a[0][0][0];
p[2 * 3 * 4] = 0;
}
void f4 (int a[1][2][3][4])
{
int *p = &a[0][0][0][0];
p[1 * 2 * 3 * 4] = 0;
}
z.c: In function ‘f1’:
z.c:4:4: warning: array subscript 4 is outside array bounds of ‘int[4]’
[-Warray-bounds]
4 | p[4] = 0;
| ~^~~
z.c:1:14: note: while referencing ‘a’
1 | void f1 (int a[4])
| ~~~~^~~~
z.c: In function ‘f2’:
z.c:10:4: warning: array subscript 12 is outside array bounds of ‘int[3]’
[-Warray-bounds]
10 | p[3 * 4] = 0;
| ~^~~~~~~
z.c:7:14: note: while referencing ‘a’
7 | void f2 (int a[3][4])
| ~~~~^~~~~~~
z.c: In function ‘f3’:
z.c:16:4: warning: array subscript 24 is outside array bounds of ‘int[2][4]’
[-Warray-bounds]
16 | p[2 * 3 * 4] = 0;
| ~^~~~~~~~~~~
z.c:13:14: note: while referencing ‘a’
13 | void f3 (int a[2][3][4])
| ~~~~^~~~~~~~~~
z.c: In function ‘f4’:
z.c:16:16: warning: array subscript 24 is outside array bounds of
‘int[1][3][4]’ [-Warray-bounds]
16 | p[2 * 3 * 4] = 0;
| ~~~~~~~~~~~~~^~~
z.c:19:14: note: while referencing ‘a’
19 | void f4 (int a[1][2][3][4])
| ~~~~^~~~~~~~~~~~~
