[LLVMdev] Order of Basic Blocks

[Ryan Taylor]

Actually, I apologize, this worked like a charm, I was looking at the wrong
readout. Thanks a lot!

On Mon, Nov 21, 2011 at 10:30 AM, Ryan Taylor <ryta1203 at gmail.com> wrote:

>
>
> ---------- Forwarded message ----------
> From: Ryan Taylor <ryta1203 at gmail.com>
> Date: Mon, Nov 21, 2011 at 10:30 AM
> Subject: Re: [LLVMdev] Order of Basic Blocks
> To: Benjamin Kramer <benny.kra at googlemail.com>
>
>
> This worked, though the RPO_iterator apparently wasn't what I was looking
> for anyways, it seems it doesn't rreally go top->down.
>
> I have a simple example code, where the block follow this path:
>
> BB0->BB1 (T), BB8 (F)
> BB1-> BB2 (T), BB3 (F)
> BB2-> BB4
> BB3-> BB5
> BB4-> BB6
> BB5-> BB8 (T), BB5 (F)
> BB6-> BB7 (T), BB4 (F)
> BB7-> BB8 (T), BB4 (F)
> BB8 (end)
>
> So, this is the basic block flow graph. When I iterate using the
> ReversePostOrderTraversal iterator, the basic blocks vistied are in this
> order:
>
> BB0, BB1, BB3, BB2, BB7, BB6, BB4, BB5, BB8
>
> Can someone explain why this is and how the BBs are stored so that I can
> either go top->down or more prefably, depth first search (from the given
> graph above)?
>
> Thanks.
>
>
>
> On Mon, Nov 21, 2011 at 10:14 AM, Benjamin Kramer <
> benny.kra at googlemail.com> wrote:
>
>>
>> On 21.11.2011, at 19:07, Ryan Taylor wrote:
>>
>> > Is there a way to cast the rpo_iterator to a basic block pointer? I
>> need to use the functions of the class Basic Block.
>>
>> Dereference it.
>>
>> - Ben
>>
>>
>> >
>> > On Sun, Nov 20, 2011 at 3:15 PM, Ryan Taylor <ryta1203 at gmail.com>
>> wrote:
>> > Sorry, forgot to add group to CC.
>> >
>> > On Sun, Nov 20, 2011 at 6:14 PM, Ryan Taylor <ryta1203 at gmail.com>
>> wrote:
>> > Cameron,
>> >
>> >   To make it less vague, I would ideally like to traverse top down. I
>> believe what you suggested is what I want, I will have a look at it.
>> >
>> >   Currently, I am iterating over the BBs in a Function, so
>> Function::iterator BBitr=F->begin(), BBitrE=F->end();
>> BBitr!=BBitrE;++BBitr, does that help clarify what I'm looking for? With
>> this current iteration method, I seem to sometimes get top down but other
>> times get bottom up and sometimes it starts top down then jumps to the
>> bottom and goes bottom up. Is there a reason for this randomness?
>> >
>> > On Sun, Nov 20, 2011 at 6:10 PM, Cameron Zwarich <zwarich at apple.com>
>> wrote:
>> > Your question is a bit vague, but you probably want
>> ReversePostOrderTraversal from include/llvm/ADT/PostOrderIterator.h.
>> >
>> > Cameron
>> >
>> > On Nov 20, 2011, at 3:00 PM, Ryan Taylor wrote:
>> >
>> > > LLVMers,
>> > >
>> > >   Is there any way to guarantee iteration of the basic blocks from
>> top down or path to path? Currently it looks sort of semi-random, sometimes
>> visiting loop heads first and other times loop tails, is there a way I can
>> visit the BBs top down or path to path?
>> > >
>> > > Thank you.
>> > > _______________________________________________
>> > > LLVM Developers mailing list
>> > > LLVMdev at cs.uiuc.edu         http://llvm.cs.uiuc.edu
>> > > http://lists.cs.uiuc.edu/mailman/listinfo/llvmdev
>> >
>> >
>> >
>> >
>> > _______________________________________________
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>>
>>
>
>
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