llvm dev - Feb 2015 - [LLVMdev] Calculate LoopInfo again

Hello,
I am iterating over loops using LoopInfo iterator. If a condition satisfies
on some loop, I change the loop body and remove it from that particular
loop. Also, I remove all incoming edges to the loop header, latch and
preHeader. Hence, these will be the unreachable blocks in the function.

If that condition satisfies, then I start iterating the loops from the
beginning skipping the modified loop. So, I need to re-calculate the
LoopInfo.

How to build LoopInfo again with the updated CFG structure?

If I just call getAnalysis<LoopInfo>() again, the modified loop will still
be present in it.

-- 
Regards,
Sridhar
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You can re-create LoopInfo from updated dominator tree.
Just update dominator tree for function and check LoopInfo::Analyze for new
LoopInfo.

Regards,
Ashutosh

From: llvmdev-bounces at cs.uiuc.edu [mailto:llvmdev-bounces at cs.uiuc.edu] On
Behalf Of Sridhar G
Sent: Wednesday, February 25, 2015 11:28 AM
To: llvmdev at cs.uiuc.edu
Subject: [LLVMdev] Calculate LoopInfo again

Hello,
I am iterating over loops using LoopInfo iterator. If a condition satisfies on
some loop, I change the loop body and remove it from that particular loop. Also,
I remove all incoming edges to the loop header, latch and preHeader. Hence,
these will be the unreachable blocks in the function.

If that condition satisfies, then I start iterating the loops from the beginning
skipping the modified loop. So, I need to re-calculate the LoopInfo.

How to build LoopInfo again with the updated CFG structure?

If I just call getAnalysis<LoopInfo>() again, the modified loop will still
be present in it.

--
Regards,
Sridhar
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