[Bug middle-end/40106] Time increase for the Polyhedron test air.f90 due to bad optimization

[rguenther at suse dot de]

------- Comment #27 from rguenther at suse dot de  2009-08-31 15:23 -------
Subject: Re:  Time increase for the Polyhedron test
 air.f90 due to bad optimization

On Mon, 31 Aug 2009, jv244 at cam dot ac dot uk wrote:

> ------- Comment #26 from jv244 at cam dot ac dot uk  2009-08-31 15:20 -------
> (In reply to comment #25)
> > -                                      if (npx[(integer(kind=8)) i + -1] + 1 >
> > j)
> > +                                      if (NON_LVALUE_EXPR
> > <npx[(integer(kind=8)) i + -1]> >= j)> where NON_LVALUE_EXPR appear when the test is compiled without
> > -fno-strict-overflow.
> 
> I wonder if this is a case where the optimizers would benefit from exploiting
> the fact that in Fortran integers can never overflow in a valid program ?

In fact it does with -fstrict-overflow.

Richard.


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http://gcc.gnu.org/bugzilla/show_bug.cgi?id=40106