[Bug tree-optimization/51721] New: -Warray-bounds false positives and inconsistencies
vincent-gcc at vinc17 dot net
gcc-bugzilla@gcc.gnu.org
Sat Dec 31 01:51:00 GMT 2011
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=51721
Bug #: 51721
Summary: -Warray-bounds false positives and inconsistencies
Classification: Unclassified
Product: gcc
Version: 4.6.2
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: tree-optimization
AssignedTo: unassigned@gcc.gnu.org
ReportedBy: vincent-gcc@vinc17.net
I get strange -Warray-bounds false positives on the following code:
static int a[10], b[10], c[10], d[10];
unsigned int f (unsigned int v)
{
return v == 17 ? 11 : v;
}
unsigned int g (unsigned int v)
{
return v == 17 ? 17 : v;
}
void t (unsigned int s)
{
if (s >> 1 == 0)
{
a[f(s)] = 0;
a[f(s)] = 0;
b[f(s)] = 0;
c[g(s)] = 0;
c[g(s)] = 0;
d[H(s)] = 0;
}
}
With gcc (Debian 4.6.2-9) 4.6.2 on a Debian/x86_64 machine:
$ gcc-snapshot -O2 -Warray-bounds -c bounds.c -DH=f
bounds.c: In function 't':
bounds.c:17:8: warning: array subscript is above array bounds [-Warray-bounds]
bounds.c:19:8: warning: array subscript is above array bounds [-Warray-bounds]
bounds.c:20:8: warning: array subscript is above array bounds [-Warray-bounds]
$ gcc-snapshot -O2 -Warray-bounds -c bounds.c -DH=g
bounds.c: In function 't':
bounds.c:17:8: warning: array subscript is above array bounds [-Warray-bounds]
Note: line 17 is the first "a[f(s)] = 0;".
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