[PATCH] D118472: [LoopPeel] Check for non-LCSSA form loops

[Max Kazantsev via Phabricator via llvm-commits]

mkazantsev requested changes to this revision.
mkazantsev added a comment.
This revision now requires changes to proceed.

This patch does not account for the fact that `DT` and `LI` can both be `nullptr`. I think it may be reasonable to lift this restriction, but so far the pass supports this case. If you can't go w/o `DT` and `LI`, then we first need to rework the pass in a way that it always expects `DT` and `LI`.



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Comment at: llvm/lib/Transforms/Scalar/LoopFuse.cpp:195
+        GuardBranch(L->getLoopGuardBranch()), PP(PP),
+        AbleToPeel(canPeel(L, *(const_cast<DominatorTree *>(DT)), *LI)),
+        Peeled(false), DT(DT), PDT(PDT), LI(LI), ORE(ORE) {
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Loop peeling pass is not guaranteed to be provided with `DT` and `LI`. They can both be (and sometimes are) nullptr, at least in old PM.


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Comment at: llvm/lib/Transforms/Utils/LoopPeel.cpp:748
   assert(PeelCount > 0 && "Attempt to peel out zero iterations?");
-  assert(canPeel(L) && "Attempt to peel a loop which is not peelable?");
+  assert(canPeel(L, *DT, *LI) && "Attempt to peel a loop which is not peelable?");
 
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This should also work for `DT == nullptr`, see checks below (line 764).


Repository:
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https://reviews.llvm.org/D118472