Re: GCC 3.3.1 -O2 problem with sqrt.c

[Sanjiv Kumar Gupta <skgnu at yahoo dot com>]

Ian,
I am attaching full .greg file here, in case
it helps. I don't know whether gcc mail server
accepts attachments or not, hence didn't send
it to the list.

Thanks
Sanjiv

--- Ian Lance Taylor <ian@airs.com> wrote:

> Sanjiv Kumar Gupta <skgnu@yahoo.com> writes:
> 
> > I am using gcc 3.3.1 release as my port, and looks
> > like I have hit a problem with greg.
> 
> You neglected to mention what target you are using.
> 
> > I couldn't understand why the insns 620 and 621
> are
> > being generated here as DI moves.
> 
> I'm not sure specifically why it got a DI move here,
> but it doesn't
> look wrong.  It's treating the struct named parts as
> DImode.
> 
> > This is creating problem since insn 621 gets
> splitted
> > after reload into two SI moves,i.e. @(r21, -8) and
> > @(r21, -4).
> > This renders insns 619 as dead and hence insns 618
> and
> > insn 429 as dead, which are eliminated by flow2.
> 
> It does look rather suspicious, but it's hard to
> know whether it is
> wrong without seeing the value in r1.
> 
> Does the behaviour change if you use
> -fno-strict-aliasing?  (I can't
> remember what the default was in 3.3.1).
> 
> Ian
> 


		
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Attachment: sqrt.c.24.greg
Description: 582424730-sqrt.c.24.greg

Attachment: sqrt.c.23.lreg
Description: 4049535085-sqrt.c.23.lreg