optimization removes a __builtin_memcpy?

[Steve Kargl]

On Sun, Nov 30, 2008 at 07:56:51PM +0100, Paul Richard Thomas wrote:
> Dear Richard,
> 
> >> The diff shows that the fails case correctly has dlen=30
> >> and in fact for any value less than slen=44 and -O[123]
> >> removes the __builtin_memcpy().  So what is missing or
> >> how to I inhibit this optimization?
> >
> > You cannot inhibit this optimization, instead the optimization should be
> > fixed to not generate invalid gimple ;)  (see builtins.c:fold_builtin_memory_op)
> >
> 
> Your comment is a bit opaque, to me at least:-)  I looked at
> builtins.c:fold_builtin_memory_op and figured out that if dest or src
> are not pointer types the call does not get inlined.  Does this
> matter?
> 
> Steve, does the code work?
> 

I have a working patch.  Unfortunately, I had to move my trip
to Washington DC up by a day, so was sitting on an airplane 
for 5 hours yesterday.  I'll submit a patch sometime this
week.

Richard's comment helped to the extent that I read through
trans.c with a bit more care.  In the end, telling someone
with my background to look at builtins.c:fold_builtin_memory_op
is tantamount to telling a blind person to look at a Picasso.

-- 
Steve