Anna Thomas 186ef38175 [Loop Deletion] Delete loops that are never executed ... Summary: Currently, loop deletion deletes loop where the only values that are used outside the loop are loop-invariant. This patch adds logic to delete loops where the loop is proven to be never executed (i.e. the only predecessor of the loop preheader has a constant conditional branch as terminator, and the preheader is not the taken target). This will remove loops that become dead after loop-unswitching generates constant conditional branches. The next steps are: 1. moving the loop deletion implementation to LoopUtils. 2. Add logic in loop-simplifyCFG which will support changing conditional constant branches to unconditional branches. If loops become unreachable in this process, they can be removed using `deleteDeadLoop` function. Reviewers: chandlerc, efriedma, sanjoy, reames Reviewed by: sanjoy Subscribers: mzolotukhin, llvm-commits Differential Revision: https://reviews.llvm.org/D32494 llvm-svn: 302015		2017-05-03 11:47:11 +00:00
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2007-07-23-InfiniteLoop.ll
2008-05-06-Phi.ll
2011-06-21-phioperands.ll
dcetest.ll
invalidation.ll
multiple-exit-conditions.ll
multiple-exits.ll
simplify-then-delete.ll
unreachable-loops.ll	[Loop Deletion] Delete loops that are never executed	2017-05-03 11:47:11 +00:00
update-scev.ll