Re: PATCH:[darwin] fix load of a misaligned double word

[Bradley Lucier <lucier at math dot purdue dot edu>]

I have a few questions about this patch.

First, I can't find a message where it's been approved, but it was 
committed in

http://gcc.gnu.org/ml/gcc-cvs/2003-12/msg00850.html

Second, I hit this problem myself, and now my code compiles with the 
FSF compiler with -mcpu=G5, but my FFT code is 10-20% slower than 
before with -mcpu=G4 -mtune=G5.  So I'm wondering if this is the right 
thing to do.

The Apple assembler was complaining about addresses like 3(r4) for 
loads and stores of floating-point values.   If the value of r4 here is 
equal to 5 modulo 8, then this seems like a properly aligned memory 
address according to the PowerPC programming manuals.  Gambit is very 
careful to align doubles on 8-byte boundaries, but these are accessed 
through char * pointers something like

*(double *)((char *)p+3)

and this generated the misaligned messages like the one mentioned in

http://gcc.gnu.org/ml/gcc-patches/2003-12/msg01788.html

So is gcc at fault and needs to be fixed, as this patch implies, or is 
Apple's assembler?  Or do I just not understand what's going on here?

Brad