Re: [RFC] Contributing tree-ssa to mainline

[Paul Brook <paul at codesourcery dot com>]

On Monday 19 January 2004 12:26 pm, Richard Kenner wrote:
> A case I know about in Ada is check elimination.  Because the default for
> Ada is enabling checking, it's quite important to eliminate checks that can
> be proven not to fail.  Theoretically, a lot this could be
> language-independent optimizers by value range propagation and related
> optimizations.  But the front-end can do a much better job because it has
> information only it knows. Moreover, by suppressing the check before
> generating any code for it, compilation time is reduced.  I think this is
> clearly the proper place for that optimization.

I don't know what form of checking is performed in Ada, but optimizations to 
remove array bound checks would also be useful for fortran. Particularly 
Fortran90 where it is much more common to know the shape of an array.

Admittedly -fbounds-check is turned on by default in fortran, but neither is 
-O2.

Paul