https://gcc.gnu.org/bugzilla/show_bug.cgi?id=117574
Richard Biener <rguenth at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Status|NEW |ASSIGNED
Assignee|unassigned at gcc dot gnu.org |rguenth at gcc dot
gnu.org
--- Comment #9 from Richard Biener <rguenth at gcc dot gnu.org> ---
So before IVCANON we have a loop-header copy that will enter the loop:
if (_8 >= _10) // 76 >= 40
goto <bb 13>; [89.00%] // enter loop
else
goto <bb 7>; [11.00%] // skip it
and the first loop jump
<bb 6> [local count: 955630224]:
# g_33 = PHI <g_21(15), _10(13)>
# b_lsm.12_28 = PHI <_20(15), b_lsm.12_30(13)>
_20 = b_lsm.12_28 + g_33;
g_21 = g_33 + 50;
if (_8 >= g_21) // 76 >= 90
goto <bb 15>; [89.00%] // loop
else
goto <bb 17>; [11.00%] // exit
should exit the loop. We enter number_of_iterations_lt with
{ (long int) ((int) d.3_5 + 40) + 50, +, 50 } and (long int) ((int) d.3_5 + 76)
+ 1
computing delta == 18446744073709551603 (aka -13u) and then
number_of_iterations_lt_to_ne computes we can convert this to NE with
a final value of 34 and a { 0, +, 50 } IV. I will dig further.
