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Re: [PATCH] var-tracking.c speedups


On Wed, Jun 24, 2009 at 01:28:51PM +0200, Michael Matz wrote:
> Hi,
> 
> On Tue, 23 Jun 2009, Jakub Jelinek wrote:
> 
> > BTW, var-tracking.c calls rtx_equal_p in a weird way:
> >                   if ((REG_P (vui[jj].lc->loc)
> >                        && REG_P (node->loc)
> >                        && REGNO (vui[jj].lc->loc) == REGNO (node->loc))
> >                       || rtx_equal_p (vui[jj].lc->loc, node->loc))
> > If that is because it doesn't care about REG mode, when it already knows
> > that it is a REG it shouldn't call rtx_equal_p at all.
> 
> It has to ignore the mode.  A hardreg contains some new value no matter 
> which mode it was in and no matter what mode the value currently in that
> hardreg had.

Ok.  Still, if REG_P (vui[jj].lc->loc), then everything we wanted to check
has been already checked, so the call to rtx_equal_p will return always
false.

	Jakub


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