[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.

[escha via llvm-commits]

escha added a comment.

Yeah, I understand that it's way more complex (and breaks LCSSA); I was more curious about whether there were cases where:

LoopPassManager [ loop passes A -> LoopSimplifyCFG -> loop passes B ]
SimplifyCFG

does worse than

LoopPassManager [ loop passes A ]
SimplifyCFG
LoopPassManager [ loop passes B ]

in other words, cases where having the primary SimplifyCFG after "loop passes B" caused us to miss things in "loop passes B" that we care about.


http://reviews.llvm.org/D17442