[Bug tree-optimization/62630] [5 regression] gcc.dg/graphite/vect-pr43423.c FAILs

[mircea.namolaru at inria dot fr]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=62630

--- Comment #16 from Mircea Namolaru <mircea.namolaru at inria dot fr> ---
Yes, but it seems to me that the cast (not in the original code) should not
be generated at all if it could not be guaranteed that the casted-to type is
larger 
enough to accommodate it. Otherwise you introduce a cast from a longer signed
type
to a shorter signed one whose behaviour is undefined by the C standard and was
not
in the original code.

So the cast in the following code is problematic (when
graphite_IV, a signed long is not in the range of a signed int).

       _56 = (intD.6) graphite_IV.5_53;
       _55 = aD.1830[_56];

The solution to fix this is to made Graphite not to generate
casts like this. An alternative is to infer the range of
graphite_IV like you do and remove the cast (but this seems more complicated
and risky as the analysis may not succeed and the problematic cast is not
removed).