[llvm] [SandboxIR][Tracker] Track eraseFromParent() (PR #99431)

[Arthur Eubanks via llvm-commits]

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@@ -41,6 +41,62 @@ Tracker::~Tracker() {
   assert(Changes.empty() && "You must accept or revert changes!");
 }
 
+EraseFromParent::EraseFromParent(std::unique_ptr<sandboxir::Value> &&ErasedIPtr,
+                                 Tracker &Tracker)
+    : IRChangeBase(Tracker), ErasedIPtr(std::move(ErasedIPtr)) {
+  auto *I = cast<Instruction>(this->ErasedIPtr.get());
+  auto LLVMInstrs = I->getLLVMInstrs();
+  // Iterate in reverse program order.
+  for (auto *LLVMI : reverse(LLVMInstrs)) {
+    SmallVector<InstrData::OpData> OpDataVec;
+    for (auto [OpNum, Use] : enumerate(LLVMI->operands()))
+      OpDataVec.push_back({Use.get(), static_cast<unsigned>(OpNum)});
+    InstrData.push_back({OpDataVec, LLVMI});
+  }
+#ifndef NDEBUG
----------------
aeubanks wrote:

no need for `ifdef NDEBUG`, the code should optimize away in a non-asserts build. unsure if need to `[[maybe_unused]]` `Idx`

https://github.com/llvm/llvm-project/pull/99431