Re: thanks for the memory work

[law at redhat dot com]

In message <1069809446.22241.2045.camel@p4>, Andrew MacLeod writes:
 >> > So an interesting question then becomes can we _cleanly_ avoid use of the
 >> > varray in the general case.   That would reduce the number of operand
 >> >varrays
 >> 
 >
 >We can.
Good.


 >> I think the iterator API + some magic to recognize most common cases
 >> would do the job here.  I plan to look into this once I get my patches
 >> queue shorter, but I won't mind anyone beating me :)
 >> 
 >
 >I think we'll pay a penalty if we don't cache the information and
 >instead try to recreate it each time, even for the common cases. Too
 >many ifs executed all the time. I certainly write code assuming that use
 >and def access is quick.
That is certainly a concern.  In fact that's one of the reasons why I
wasn't even going to consider special casing uses, vdefs or vuses.  
defs is the only one I thought that it might make sense to consider.


 >As I discussed earlier, I plan to make all the real USE and DEF ops for
 >all the stmt's come out of a single array, or be cached in the
 >annotation for the common case like immediate_uses works now. Whichever
 >works out best.  
Even if they come out of a single array, I don't see how that necessarily
helps the memory consumption problems -- since you've still got to
provide the operand walkers indices into that array.

jeff