[Bug tree-optimization/32367] [4.3 Regression] internal compiler error: in build_polynomial_chrec, at tree-chrec.h:113

["pinskia at gcc dot gnu dot org" <gcc-bugzilla@gcc.gnu.org>]

------- Comment #3 from pinskia at gcc dot gnu dot org  2007-06-16 20:03 -------
The chrec is
{{&BinomialCoefficients[0], +, 4}_1, +, {0, +, 4}_1}_1

Which looks ok and correct.

the comment before chrec_component_in_loop_num, says:
/* Returns the evolution part of CHREC in LOOP_NUM when RIGHT is
   true, otherwise returns the initial condition in LOOP_NUM.  */


So the initialize condition here is &BinomialCoefficients[0] p+ 0.

I guess this part needs a fixing.

Note we get in build_polynomial_chrec:
(gdb) p debug_generic_expr (left)
&BinomialCoefficients[0]
$16 = void
(gdb) p debug_generic_expr (right)
{&BinomialCoefficients[0], +, 4}_1

Which does not make sense at all, since we are going to create:
{&BinomialCoefficients[0], +, {&BinomialCoefficients[0], +, 4}_1 }_1

So that means the initialize condition that returns is:
&BinomialCoefficients[0] + &BinomialCoefficients[0]

Which really does not makes any sense at all.

So I just exposed a latent bug in chrec_component_in_loop_num.


-- 

pinskia at gcc dot gnu dot org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|UNCONFIRMED                 |NEW
     Ever Confirmed|0                           |1
   Last reconfirmed|0000-00-00 00:00:00         |2007-06-16 20:03:48
               date|                            |


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=32367