[Bug tree-optimization/50439] gfortran infinite loop with -floop-interchange

[wschmidt at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=50439

--- Comment #1 from William J. Schmidt <wschmidt at gcc dot gnu.org> 2012-04-05 16:47:32 UTC ---
I verified that the looping occurs inside the PPL library, on a call to
ppl_PIP_Problem_is_satisfiable.  I used ppl_PIP_Problem_ascii_dump to examine
the "pip" variable passed into that routine:

external_space_dim: 32

internal_space_dim: 0

input_cs( 38 )
size 33 0 0 162 0 1 0 9 0 1620 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 -1
f -RPI_V -RPI  -NNC_V -NNC
size 33 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 0 f
-RPI_V -RPI  -NNC_V -NNC
size 33 -1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 0 0 f
-RPI_V -RPI  -NNC_V -NNC
size 33 0 0 162 0 1 0 9 0 1620 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 -1 0 0 0
f -RPI_V -RPI  -NNC_V -NNC
size 33 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 0 0 0 0 f
-RPI_V -RPI  -NNC_V -NNC
size 33 -1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 0 0 0 0 0 f
-RPI_V -RPI  -NNC_V -NNC
size 33 0 0 162 0 1 0 9 0 1620 0 0 0 0 0 0 -162 0 -1 0 -9 0 0 0 0 0 0 -1620 0 0
0 0 0 0 f -RPI_V -RPI  -NNC_V -NNC
size 33 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 0 0 0 0 0 0 0 0 0 -1 0 0 0 0 0 0 0 f
-RPI_V -RPI  -NNC_V -NNC
size 33 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 0 0 0 0 -1 0 0 0 0 0 0 0 0 f
-RPI_V -RPI  -NNC_V -NNC
size 33 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 0 0 0 0 0 -1 0 0 0 0 0 0 0 0 0 f
-RPI_V -RPI  -NNC_V -NNC
size 33 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 0 0 0 0 0 0 0 0 0 0 f
-RPI_V -RPI  -NNC_V -NNC
size 33 0 0 162 0 1 0 9 0 1620 0 0 0 0 0 0 -162 0 -1 0 -9 0 -1620 0 0 0 0 0 0 0
0 0 0 0 f -RPI_V -RPI  -NNC_V -NNC
size 33 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 0 0 0 0 0 0 0 0 0 0 0 0 f
-RPI_V -RPI  -NNC_V -NNC
size 33 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 f
-RPI_V -RPI  -NNC_V -NNC
size 33 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 f
-RPI_V -RPI  -NNC_V -NNC
size 33 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 f
-RPI_V -RPI  -NNC_V -NNC
size 33 0 0 0 0 0 0 0 0 1 0 0 0 0 -1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 f
-RPI_V -RPI  -NNC_V -NNC
size 33 0 0 1 0 0 0 0 0 0 0 0 0 -1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 f
-RPI_V -RPI  -NNC_V -NNC
size 33 0 0 0 0 0 0 1 0 0 0 0 -1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 f
-RPI_V -RPI  -NNC_V -NNC
size 33 0 0 0 0 1 0 0 0 0 0 -1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 f
-RPI_V -RPI  -NNC_V -NNC
size 33 0 0 0 0 0 0 0 0 0 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 f
-RPI_V -RPI  -NNC_V -NNC
size 33 0 0 0 0 0 0 0 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 f
-RPI_V -RPI  -NNC_V -NNC
size 33 0 0 0 0 0 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 f
-RPI_V -RPI  -NNC_V -NNC
size 33 0 0 0 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 f
-RPI_V -RPI  -NNC_V -NNC
size 33 0 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 f
-RPI_V -RPI  -NNC_V -NNC
size 33 -1 0 1 0 0 0 0 0 0 0 0 0 0 0 0 -1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 f
-RPI_V +RPI  -NNC_V -NNC
size 33 0 0 0 0 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 f
-RPI_V +RPI  -NNC_V -NNC
size 33 6480 0 -162 0 -1 0 -9 0 -1620 0 0 0 0 0 0 162 0 1 0 9 0 0 0 0 0 0 0 0 0
0 0 0 0 f -RPI_V +RPI  -NNC_V -NNC
size 33 9 0 -1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 f
-RPI_V +RPI  -NNC_V -NNC
size 33 8 0 0 0 -1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 f
-RPI_V +RPI  -NNC_V -NNC
size 33 17 0 0 0 0 0 -1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 f
-RPI_V +RPI  -NNC_V -NNC
size 33 0 0 0 0 0 0 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 f
-RPI_V +RPI  -NNC_V -NNC
size 33 8 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 -1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 f
-RPI_V +RPI  -NNC_V -NNC
size 33 17 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 -1 0 0 0 0 0 0 0 0 0 0 0 0 0 f
-RPI_V +RPI  -NNC_V -NNC
size 33 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 0 0 0 0 0 0 0 0 0 0 0 0 0 f
-RPI_V +RPI  -NNC_V -NNC
size 33 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 f
-RPI_V +RPI  -NNC_V -NNC
size 33 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 f
-RPI_V +RPI  -NNC_V -NNC
size 33 0 0 0 0 0 0 0 0 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 f
-RPI_V +RPI  -NNC_V -NNC

first_pending_constraint: 0

status: PARTIALLY_SATISFIABLE

parameters
variables( 0 )

initial_context
0 x 0

control_parameters
CUTTING_STRATEGY_FIRST
PIVOT_ROW_STRATEGY_FIRST

big_parameter_dimension: 18446744073709551615

current_solution: BOTTOM


It appears we'll need to report this to the PPL folks.  I'll get an account
over there and point them to this PR.