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Re: [Lto-team] Fwd: [tuples] reduced testcase of the libjava build failure


On Fri, May 2, 2008 at 12:00 PM, Rafael Espindola <espindola@google.com> wrote:
> >
>  >  IMHO if such comparison may trap then we need to gimplify to
>  >
>  >  <bb>
>  >   ...
>  >   bool tmp = a < b;
>  >
>  >  <bb>
>  >   if (tmp)
>  >      ....
>
>  That is interesting. IMHO we should change GIMPLE_COND to have only a
>  boolean variable. My only argument for that is that it would make the
>  IL more simple, since there would be only one place to look for
>  comparisons (on GIMPLE_ASSIGN).
>
>  This problems looks like a more convincing argument. What do you think about it?

It also would help SCCVN because all comparisons will have an SSA_NAME
associated.  I can imagine (optimization) problems with 1) expand,
2) forwprop (it does COND_EXPR operand combining), 3) vrp and DOM
for the same reason, 4) ifcombine.   And of course with all the others
I forgot ;)

IMHO a worthwhile simplification in general, but not necessary for the
immediate problem.

Richard.


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