On Thu, Feb 23, 2012 at 10:11 PM, Aldy Hernandez <al...@redhat.com> wrote:
> On 02/23/12 12:19, Aldy Hernandez wrote:
>
>> about hit me. Instead now I save all loads in a function and iterate
>> through them in a brute force way. I'd like to rewrite this into a hash
>> of some sort, but before I go any further I'm interested to know if the
>> main idea is ok.
>
>
> For the record, it may be ideal to reuse some of the iterations we already
> do over the function's basic blocks, so we don't have to iterate yet again
> over the IL stream. Though it may complicate the pass unnecessarily.
It's definitely ugly that you need to do this. And yes, you have to look at
very many passes I guess, PRE comes to my mind at least.
I still do not understand the situation very well, at least why for
transaction { for () if (b) load; } load;
it should be safe to hoist load out of the transaction while for
load; transaction { for () if (b) load; }
it is not. Neither do I understand why it's not ok for
transaction { for () if (b) load; }
to hoist the load out of the transaction.
I assume all the issue is about hoisting things over the trasaction start.
So - why does the transaction start not simply clobber all global memory?
That would avoid the hoisting. I assume that transforming the above to
transaction { tem = load; for () if (b) = tem; }
is ok?
Thanks,
Richard.
