[Bug rtl-optimization/31849] [4.2/4.3 Regression] Code size regression caused by fix to PR 31360

[rakdver at kam dot mff dot cuni dot cz]

------- Comment #5 from rakdver at kam dot mff dot cuni dot cz  2007-05-07 09:38 -------
Subject: Re:  [4.2/4.3 Regression] Code size regression caused by fix to PR
31360

> (In reply to comment #2)
> > > 1) Hoists a register containing 0 out of the loop
> > The correct thing to do.
> >
> Not necessarily.  Hoisting literal constants means that opportunities to simply
> insns based on that constant are potentially lost.

This could be prevented if invariant motion added equivalence notes;
nevertheless,
one could argue that such simplifications should have been performed
before loop invariant motion (in cse).


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=31849