[PATCH] D39760: [SimplifyCFG] Teach merge conditional stores to handle cases where the PostBB has more than 2 predecessors by inserting a new block for the store.

[Eli Friedman via Phabricator via llvm-commits]

efriedma added a comment.

Do you know how much impact this has, in the sense of making this transform trigger more often in benchmarks?



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Comment at: lib/Transforms/Utils/SimplifyCFG.cpp:2956
+  // sink the store.
+  if (std::next(pred_begin(PostBB), 2) != pred_end(PostBB)) {
+    BasicBlock *TruePred = QTB ? QTB : QFB->getSinglePredecessor();
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You might want to explicitly note what is known about the terminators of QTB/QFB here; pred_begin can return a block multiple times in cases where a terminator contains multiple uses of a successor.  (I don't think you can hit that case here, but it took me a few minutes to convince myself.)


https://reviews.llvm.org/D39760