[FFmpeg-cvslog] r18936 - in trunk/libavcodec: Makefile mlpdsp.c

[Alexander Strange]

On May 25, 2009, at 4:02 PM, Reimar D?ffinger wrote:

> On Mon, May 25, 2009 at 04:42:28PM -0300, Ramiro Polla wrote:
>> I still don't really understand what llvm is complaining about, but  
>> is
>> there a way to make llvm stop complaining without altering the object
>> code in gcc? There should be a way to correctly specify this...
>>
>> Besides, how bad can a cast to the same type be?
>
> Sorry, I missed that readval is "r" for 64 bit.
> In that case, I think that's a bug in LLVM, it should ignore nop-casts
> (the types are exactly the same).

I think it's reasonable; newer gcc rejects it in C:

int as(int a)
{
     asm ("" : : "m"((int)a));
}

int c(int a)
{
     return *&((int)a);
}

 > gcc-4.2 -S test.c
test.c: In function ?c?:
test.c:8: warning: argument to '&' not really an lvalue; this will be  
a hard error in the future
 > /usr/local/gcc45/bin/gcc -S test.c
test.c: In function 'c':
test.c:8: error: lvalue required as unary '&' operand

There's not really any difference, so it may just be an oversight that  
gcc doesn't at least warn about it.