Re: [PATCH] [C++] speedup cp_tree_chain_matters_p

[Andrew Pinski <pinskia at physics dot uc dot edu>]

On Mar 30, 2004, at 03:12, Zack Weinberg wrote:

> Andrew Pinski <pinskia@physics.uc.edu> writes:
>
> > This patch speeds up cp_tree_chain_matters_p by allowing the last call
> > be sibcalled.
> >
> > Bootstrapped and tested on powerpc-apple-darwin with no regressions.
> >
> > OK?
>
> No.  Find out why sibcall optimization doesn't trigger for the
> original code and fix that instead.

The reason why it is not sibcalled is because c_tree_chain_matters_p
returns an int so the || statement becomes f()!=0||g()!=0 which becomes
if (f()!=0)
  return true;
return g()!=0;

So one thing to do is change the return type c_tree_chain_matters_p to
return bool but that will still not fix it.
This example is not sibcalled at all:
_Bool f();
_Bool g();
_Bool h()
{
  return f() || g();
}

Thanks,
Andrew Pinski