[PATCH] D17442: [LPM] Remove the last worrisome split in the primary loop pass pipeline, allowing LICM and friends to always run over the outer loop after unrolling has a chance to remove the inner loop.

[Michael Zolotukhin via llvm-commits]

mzolotukhin added a comment.

Just to make it clear: I absolutely support any steps in this direction, and I'm just concerned that if we do it right now we might be hit by huge regressions. If testing proves me wrong, I'm totally happy with it:)

As for the current situation - we might need a clean-up after loop-unswitch and loop-rotate. Also, the issue is that if any of this transformations fails due to lack of cleanup, it'll create a chain reaction: others will likely also fail.

So, I think we need to test this change, and if there are major problems, try to address them first (probably, by developing LoopSimplifyCFG).


http://reviews.llvm.org/D17442