https://gcc.gnu.org/bugzilla/show_bug.cgi?id=109386
Bug ID: 109386
Summary: [13 Regression] Frange value relation related
miscompilation
Product: gcc
Version: 13.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: tree-optimization
Assignee: unassigned at gcc dot gnu.org
Reporter: jakub at gcc dot gnu.org
Target Milestone: ---
I've totally missed a regression caused by my recent frange improvements (most
likely
r13-6967-g5fe05ffefd21c4fa):
+FAIL: libphobos.phobos/std/math/algebraic.d execution test
+FAIL: libphobos.phobos_shared/std/math/algebraic.d execution test
Reduced testcase in C:
static inline float
foo (float x, float y)
{
float u = __builtin_fabsf (x);
float v = __builtin_fabsf (y);
if (!(u >= v))
{
v = u;
u = __builtin_fabsf (y);
if (__builtin_isinf (u)) return u;
if (__builtin_isinf (v)) return v;
}
return 42.0f;
}
int
main ()
{
if (!__builtin_isinf (foo (__builtin_inff (), __builtin_nanf (""))))
__builtin_abort ();
}
for -O2.
I believe the bug is that (as discussed earlier) we don't implement the full
set of VREL_* relations for the case where NAN may be seen and in this case
register VREL_LT for the if block, which is wrong, the inverse of VREL_GE is
VREL_UNLT which we don't currently have.
