[PATCH] D110060: [LoopBoundSplit] Handle the case in which exiting block is loop header

[Max Kazantsev via Phabricator via llvm-commits]

mkazantsev requested changes to this revision.
mkazantsev added inline comments.
This revision now requires changes to proceed.


================
Comment at: llvm/lib/Transforms/Scalar/LoopBoundSplit.cpp:81
+    // value from backedge.
+    if (Cond.AddRecSCEV && isa<PHINode>(Cond.AddRecValue)) {
+      PHINode *PN = cast<PHINode>(Cond.AddRecValue);
----------------
You can use `L.getLoopPreheader` or `L.getLoopPredecessor` to find a block from which a non-loop value is coming.


================
Comment at: llvm/test/Transforms/LoopBoundSplit/bug51866.ll:39
+; CHECK-NEXT:    [[I_0_SPLIT:%.*]] = phi i16 [ [[INC_SPLIT:%.*]], [[FOR_INC_SPLIT:%.*]] ], [ 5, [[FOR_COND_SPLIT_PREHEADER]] ]
+; CHECK-NEXT:    [[I_1_SPLIT:%.*]] = phi i16 [ [[INC_SPLIT]], [[FOR_INC_SPLIT]] ], [ 10, [[FOR_COND_SPLIT_PREHEADER]] ]
+; CHECK-NEXT:    [[EXITCOND_NOT_SPLIT:%.*]] = icmp eq i16 [[I_0_SPLIT]], 10
----------------
Why is it 10 again?


CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D110060/new/

https://reviews.llvm.org/D110060