[llvm] [SandboxVec][DAG] Build actual dependencies (PR #111094)

[Arthur Eubanks via llvm-commits]

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@@ -50,29 +51,137 @@ MemDGNodeIntervalBuilder::make(const Interval<Instruction> &Instrs,
                              cast<MemDGNode>(DAG.getNode(MemBotI)));
 }
 
+DependencyGraph::DependencyType
+DependencyGraph::getRoughDepType(Instruction *FromI, Instruction *ToI) {
+  // TODO: Perhaps compile-time improvement by skipping if neither is mem?
+  if (FromI->mayWriteToMemory()) {
+    if (ToI->mayReadFromMemory())
+      return DependencyType::RAW;
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aeubanks wrote:

is RAW more conservative than WAW?

https://github.com/llvm/llvm-project/pull/111094