[PATCH] D91682: [LoopInterchange] Fix the checking of tightly nested loop

[Whitney Tsang via Phabricator via llvm-commits]

Whitney added inline comments.


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Comment at: llvm/lib/Transforms/Scalar/LoopInterchange.cpp:587
 
-bool LoopInterchangeLegality::tightlyNested(Loop *OuterLoop, Loop *InnerLoop) {
-  BasicBlock *OuterLoopHeader = OuterLoop->getHeader();
-  BasicBlock *InnerLoopPreHeader = InnerLoop->getLoopPreheader();
-  BasicBlock *OuterLoopLatch = OuterLoop->getLoopLatch();
+bool LoopInterchangeLegality::tightlyNested(Loop *ParentLoop, Loop *ChildLoop) {
+  BasicBlock *ParentLoopHeader = ParentLoop->getHeader();
----------------
Is there a reason to rename Outer->Parent and Inner->Child? As all the comments still use the term inner and outer to reference the loops.


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Comment at: llvm/lib/Transforms/Scalar/LoopInterchange.cpp:1006
   // Check if the loops are tightly nested.
-  if (!tightlyNested(OuterLoop, InnerLoop)) {
-    LLVM_DEBUG(dbgs() << "Loops not tightly nested\n");
-    ORE->emit([&]() {
-      return OptimizationRemarkMissed(DEBUG_TYPE, "NotTightlyNested",
-                                      InnerLoop->getStartLoc(),
-                                      InnerLoop->getHeader())
-             << "Cannot interchange loops because they are not tightly "
-                "nested.";
-    });
-    return false;
-  }
+  Loop *ChildLoop = InnerLoop;
+  Loop *ParentLoop = nullptr;
----------------
processLoop is called with loop i and i -1, so there are no loops in between InnerLoop and OuterLoop.
Am I missing something?




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  https://reviews.llvm.org/D91682/new/

https://reviews.llvm.org/D91682