Re: [trans-mem] thread-private malloc optimizations

[Aldy Hernandez <aldyh at redhat dot com>]

> (1) Inside that loop, you need to check for self-assignment like
>     can happen in loops:
> 
> 	bb1:
> 		x_1 = ...
> 		goto bb3;
> 	bb2:
> 		x_2 = ...
> 		goto bb3;
> 	bb3:
> 		x_3 = PHI (x_1(1), x_2(2), x_3(3))
> 		...
> 		goto bb3

I can't seem to come up with a testcase to see an example.  Would I just
ignore self-assignment in the loop, that is take the result of analyzing
just x_1 and x_2?

> (2) You need to perform a MIN operation there between the old
>     retval and the one you get from the recursive call.  At the
>     moment you're promoting thread_local to transaction_local.
> 
> The rest of the patch looks ok.

That was on purpose, see comment.  The caller (requires_barrier)
generates a log for mem_thread_local, whereas there is no log created
for mem_transaction_local.  If we pass back mem_thread_local, we'd
create a log twice.  Isn't the whole purpose of knowing that all the PHI
arguments have been handled, not having to generate a log or
save/restore pair?

Aldy