https://gcc.gnu.org/bugzilla/show_bug.cgi?id=126547
Bug ID: 126547
Summary: [16/17 Regression] Wrong code with ranger and FP
division and infinities
Product: gcc
Version: 17.0
Status: UNCONFIRMED
Keywords: wrong-code
Severity: normal
Priority: P3
Component: tree-optimization
Assignee: unassigned at gcc dot gnu.org
Reporter: ktkachov at gcc dot gnu.org
Target Milestone: ---
int printf (const char *, ...);
/* a1 / a2 == +Inf does not imply that a2 is a zero: the quotient overflows to
+Inf for every a2 small enough, so the reverse range of the divisor has to
include the subnormals. Ranger derives [-0.0, +0.0] for a2 on the true
edge and the jump threader then folds "a2 > 0.0" to false there. */
__attribute__((noipa)) static int
f (unsigned int p, long double a2)
{
long double a1 = (long double) (int) (p & 7) + 1.0L; /* [1.0, 8.0] */
long double d = a1 / a2;
int n = 0;
if (d >= __builtin_infl ())
n += 1;
if (a2 > 0.0L)
n += 2;
return n;
}
int
main (void)
{
int r = f (0, __LDBL_DENORM_MIN__); /* 1.0L / 6.5e-4966L == +Inf */
printf ("%d\n", r);
if (r != 3)
__builtin_abort ();
return 0;
}
aborts at -O2 and passes at -O0
