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

[Arthur Eubanks via llvm-commits]

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@@ -99,6 +100,46 @@ class UseSet : public IRChangeBase {
 #endif
 };
 
+class EraseFromParent : public IRChangeBase {
+  /// Contains all the data we need to restore an "erased" (i.e., detached)
+  /// instruction: the instruction itself and the operands data.
+  struct InstrData {
+    /// The operand and the corresponding operand number.
+    struct OpData {
+      llvm::Value *Op;
+      unsigned OpNum;
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aeubanks wrote:

do we need this? can we just use the index from `enumerate(OpDataVec)`?

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