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From: Richard Guenther <rguenther@suse.de>
To: Diego Novillo <dnovillo@google.com>
Cc: gcc-patches@gcc.gnu.org
Subject: Re: [PATCH][RFC] Force predicate computations to separate stmts
Date: Fri, 13 Aug 2010 15:32:00 -0000	[thread overview]
Message-ID: <alpine.LNX.2.00.1008131728040.25856@zhemvz.fhfr.qr> (raw)
In-Reply-To: <4C6562CF.30901@google.com>

On Fri, 13 Aug 2010, Diego Novillo wrote:

> On 10-08-13 11:12 , Richard Guenther wrote:
> 
> > This helps streamlining the code and allows for example value-numbering
> > to do sth with these predicates (and eventually drive jump-threading
> > from it).
> 
> Nice!  This ought to help simplify VRP too.  We can move the assertions right
> after the assignments and remove the code that inserts assertions at the top
> of if-then-else blocks.

You still will have asserts 'on edges' - otherwise you don't know
if the predicate is true or false.

> > But - I'm fishing for comments (as usual) on this GIMPLE IL change.
> 
> It's an obvious and useful cleanup.  Thanks.  I have not looked at the patch,
> but I presume that it's perfectly sensible and tedious.

Heh.

> Any changes in memory usage?

I didn't yet measure memory usage or compile time (nor did I look at
all testcases that now fail).  But I would expect memory usage to
go up, not down (one gimple-assign compared to one less operand slot).

Oh, and as a followup a RHS COND_EXPR would now fit in GIMPLE_TERNARY_RHS.

Richard.

  reply	other threads:[~2010-08-13 15:30 UTC|newest]

Thread overview: 5+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2010-08-13 15:20 Richard Guenther
2010-08-13 15:22 ` Diego Novillo
2010-08-13 15:32   ` Richard Guenther [this message]
2010-08-13 15:48   ` Michael Matz
2010-08-13 16:00     ` Diego Novillo

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