https://gcc.gnu.org/bugzilla/show_bug.cgi?id=102124
Jakub Jelinek <jakub at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
CC| |jakub at gcc dot gnu.org,
| |joelh at gcc dot gnu.org,
| |rsandifo at gcc dot gnu.org
Priority|P3 |P2
Target Milestone|--- |11.3
Summary|GCC 11.2.1 |[11/12 Regression]
|-ftree-loop-vectorize |-ftree-loop-vectorize
|Causing Data To Lose Sign |Causing Data To Lose Sign
|Bit on AARCH64 Platform |Bit on AARCH64 Platform
Ever confirmed|0 |1
Status|UNCONFIRMED |NEW
Last reconfirmed| |2021-08-30
--- Comment #2 from Jakub Jelinek <jakub at gcc dot gnu.org> ---
Started with r11-5160-g9fc9573f9a5e9432e53c7de93985cfbd267f0309 .
Slightly reduced testcase:
int
foo (const unsigned char *a, const unsigned char *b, unsigned long len)
{
int ab, ba;
unsigned long i;
for (i = 0, ab = 0, ba = 0; i < len; i++)
{
ab |= a[i] - b[i];
ba |= b[i] - a[i];
}
return (ab | ba) >= 0;
}
int main ()
{
unsigned char a[32] = {'a', 'a', 'a', 'a', 'a', 'a', 'a', 'a', 'a', 'a', 'a',
'a', 'a', 'a', 'a', 'a'};
unsigned char b[32] = {'a', 'a', 'a', 'a', 'a', 'a', 'a', 'a', 'a', 'a', 'a',
'a', 'a', 'a', 'a', 'a'};
unsigned char c[32] = {'b', 'b', 'b', 'b', 'b', 'b', 'b', 'b', 'b', 'b', 'b',
'b', 'b', 'b', 'b', 'b'};
if (!foo (a, b, 16))
__builtin_abort ();
if (foo (a, c, 16))
__builtin_abort ();
return 0;
}
