[PATCH] D126456: [WIP][IPSCCP] Invalidate the Lattice Value of deleted instructions.

[Alexandros Lamprineas via Phabricator via llvm-commits]

labrinea added inline comments.


================
Comment at: llvm/lib/Transforms/Utils/SCCPSolver.cpp:1738
+    if (auto *I = dyn_cast<Instruction>(U))
+      if (I != Old && isBlockExecutable(I->getParent()))
+        UseInsts.push_back(I);
----------------
This is something weren't checking before. There can be self-referencing PHI nodes which get replaced and then we are visiting them, which results in a crash.


================
Comment at: llvm/lib/Transforms/Utils/SCCPSolver.cpp:1743-1749
+  // Remove the instruction from Block and Solver.
+  if (auto *I = dyn_cast<Instruction>(Old)) {
+    if (I->isSafeToRemove()) {
+      I->eraseFromParent();
+      removeLatticeValueFor(I);
+    }
+  }
----------------
Also this should happen first and then visit the users, otherwise the solver keeps invalid lattice state in the meantime.


Repository:
  rG LLVM Github Monorepo

CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D126456/new/

https://reviews.llvm.org/D126456