[PATCH] D26490: [GVN, OptDiag] Print the interesting instructions involved in missed load-elimination

[Hal Finkel via llvm-commits]

hfinkel added inline comments.


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Comment at: lib/Transforms/Scalar/GVN.cpp:1217
+  using namespace ore;
+  for (auto *U : LI->getPointerOperand()->users())
+    if (U != LI && (isa<LoadInst>(U) || isa<StoreInst>(U)) &&
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This iteration order is going to be non-deterministic if there are multiple users; I don't think we can do it this way. Plus, this won't really give the best answer. Unfortunately, actually giving the best answer probably needs to wait for MemorySSA/NewGVN (because looking at other pointer uses won't pick up cases where a smaller load is replaced by part of a larger store, etc.). In the mean time, can we do something deterministic (e.g. sort the other instructions by dominance, pick the last instruction in the last block (perhaps making use of OrderedBasicBlock))?


https://reviews.llvm.org/D26490