https://gcc.gnu.org/bugzilla/show_bug.cgi?id=109350
Richard Biener <rguenth at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
CC| |amacleod at redhat dot com
--- Comment #2 from Richard Biener <rguenth at gcc dot gnu.org> ---
Hmm, the same reproduces with r_imin_imax as ptrdiff_t but the IL is a bit
more obvious:
<bb 2> [local count: 1073741824]:
_27 ={v} signed_value_source;
_4 = (unsigned long) _27;
_8 = _4 + 2147483648;
if (_8 > 4294967295)
goto <bb 8>; [50.00%]
else
goto <bb 3>; [50.00%]
<bb 3> [local count: 536870913]:
_30 = _27 + 1;
_28 = (sizetype) _30;
if (_4 <= 4611686018427387900)
goto <bb 4>; [50.00%]
else
goto <bb 5>; [50.00%]
<bb 5> [local count: 268435458]:
_12 = operator new [] (18446744073709551615);
__builtin_memcpy (_12, &MEM <const char[37]> [(void
*)"0123456789abcdefghijklmnopqrstuvwxyz" + 35B], 2);
sink (_12);
if (_28 <= 4611686018427387900)
goto <bb 9>; [100.00%]
else
goto <bb 7>; [0.00%]
<bb 9> [local count: 0]:
iftmp.2_37 = _28 * 2;
_39 = operator new [] (iftmp.2_37);
__builtin_memcpy (_39, &MEM <const char[37]> [(void
*)"0123456789abcdefghijklmnopqrstuvwxyz" + 34B], 3);
so we have (unsigned long)[int_min, int_max] > 4611686018427387900
&& (unsigned long)[int_min+1, int_max+1] <= 4611686018427387900 to
constrain _4. I don't see how we can arrive at [0,0] for iftmp.2_37.
In fact if I put this into a separate testcase like
void __attribute__((noipa))
foo (long signed_value_source)
{
unsigned long temu = signed_value_source;
if (temu + 2147483648 > 4294967295)
;
else
{
long tems = signed_value_source + 1;
unsigned long temu2 = tems;
if (temu > 4611686018427387900)
if (temu2 <= 4611686018427387900)
{
unsigned long iftmp = temu2 * 2;
if (iftmp == 0)
__builtin_abort ();
}
}
}
then we optimize this to
<bb 2> [local count: 1073741824]:
temu_3 = (long unsigned int) signed_value_source_2(D);
_1 = temu_3 + 2147483648;
if (_1 > 4294967295)
goto <bb 5>; [50.00%]
else
goto <bb 3>; [50.00%]
<bb 3> [local count: 536870913]:
if (signed_value_source_2(D) == -1)
goto <bb 4>; [0.00%]
else
goto <bb 5>; [100.00%]
<bb 4> [count: 0]:
__builtin_abort ();
and the outer if doesn't change the inner range result.
