[llvm] [AMDGPU][SplitModule] Cleanup CallsExternal Handling (PR #106528)

[Matt Arsenault via llvm-commits]

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@@ -1326,13 +1362,23 @@ static void splitAMDGPUModule(
   //
   // Additionally, it guides partitioning to not duplicate this function if it's
   // called directly at some point.
-  for (auto &Fn : M) {
-    if (Fn.hasAddressTaken()) {
-      if (Fn.hasLocalLinkage()) {
-        LLVM_DEBUG(dbgs() << "[externalize] " << Fn.getName()
-                          << " because its address is taken\n");
+  //
+  // TODO: Could we be smarter about this ? This makes all functions whose
+  // addresses are taken non-copyable. We should probably model this type of
+  // constraint in the graph and use it to guide splitting, instead of
+  // externalizing like this. Maybe non-copyable should really mean "keep one
+  // visible copy, then internalize all other copies" for some functions?
+  if (!NoExternalizeOnAddrTaken) {
+    for (auto &Fn : M) {
+      // TODO: Should aliases count? Probably not but they're so rare I'm not
+      // sure it's worth fixing.
+      if (Fn.hasAddressTaken()) {
+        if (Fn.hasLocalLinkage()) {
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arsenm wrote:

Check hasLocalLinkage first 

https://github.com/llvm/llvm-project/pull/106528