|
|
| Bugzilla Link |
679 |
| Created on |
Feb 08, 2010 21:19 |
| Version |
svn |
| OS |
Linux |
| Architecture |
PC |
| Attachments |
bug676A.sac |
Extended Description
Created an attachment (id=671)
source code to reproduce fault
This is an attempt to separate Bug #676 into its essential parts...
The attached code was compiled under Build #16761:MODIFIED
with these options:
sac2c -extrema -nowlf -doawlf -check c -b11:uglf >crud
The first three options are not relevant, BTW, except for minor
differences in generated code.
Function main() contains this code:
_flat_0 = _MAIN::id( _flat_1);
_isaa_695__flat_0 = _saabind_( _isaa_675__rso_6_TheWorld, _isaa_676__rso_6_TheWorld, _flat_0);
_pinl_507__flat_5 = [ _isaa_695__flat_0 ];
_pinl_516__idc_68, _pinl_515__icc_61_pred = _non_neg_val_V_( _pinl_507__flat_5);
_pinl_510__flat_2 = [ 0 ];
_pinl_518__idc_69, _pinl_517__icc_60_pred = _non_neg_val_V_( _pinl_510__flat_2);
_pinl_523__idc_72, _pinl_522__icc_63_pred = _val_le_val_VxV_( _pinl_518__idc_69, _pinl_507__flat_5);
_pinl_528__idc_75, _pinl_527__icc_65_pred = _val_le_val_VxV_( _pinl_516__idc_68, _pinl_507__flat_5);
_pinl_575_ub_i = _max_SxS_( _isaa_675__rso_6_TheWorld, _isaa_695__flat_0);
_pinl_540__wlbsc_490_sc_bound = [ _pinl_575_ub_i ];
_wlsimp_608 = _sub_SxS_( _isaa_695__flat_0, _pinl_575_ub_i);
_pinl_506__icc_67 = with {
(_pinl_540__wlbsc_490_sc_bound <= _pinl_513__flat_6=[_pinl_514_i] < _pinl_507__flat_5 genwidth [ _wlsimp_608 ])
{
/* empty */
} : _isaa_675__rso_6_TheWorld ; ,
(_pinl_510__flat_2 <= _pinl_513__flat_6=[_pinl_514_i] < _pinl_507__flat_5 genwidth [ _isaa_695__flat_0 ])
{
/* empty */
} : _pinl_514_i ;
} :
genarray( _pinl_507__flat_5, _isaa_675__rso_6_TheWorld);
Several things are notable in this code:
1. The unguarded result of id(), _isaa_695__flat_0, is used as WL
GENERATOR_BOUND2 and in the _max_SxS_() computation.
Although semantically correct, due to the _afterguard_() that follows
the WL (not shown), it means that using the _non_neg_val_() guard
as the basis for annotating _pinl_516__idc_68 with
an AVIS_MINVAL() of zero does us no good in simplifying the
_max_SxS_() computation.
2. Similarly, the vector result of the val_le_val_VxV_() computation is
not used at all. Its semantics are saved only by the use of
its predicate result in the trailing _afterguard_().
What should be done here, I think, is the following;
Each guard should, effectively, replace all following occurrences of its
vector arguments by the appropriate result of that guard.
This would have the effect of allowing array annotations (e.g.,
AVIS_MINVAL, AVIS_MAXVAL) to propagate through the code from each
guard to the actual point(s) of use of the putative variable.
