Revert "[AMDGPU][SplitModule] Handle !callees metadata (#108802)"

This reverts commit 4a0dc3e.
Breaks tests, see comments on
llvm/llvm-project#108802

Author: nico

llvm/lib/Target/AMDGPU/AMDGPUSplitModule.cpp

@@ -482,29 +482,6 @@ void SplitGraph::Node::visitAllDependencies(
   }
 }
 
-/// Checks if \p I has MD_callees and if it does, parse it and put the function
-/// in \p Callees.
-///
-/// \returns true if there was metadata and it was parsed correctly. false if
-/// there was no MD or if it contained unknown entries and parsing failed.
-/// If this returns false, \p Callees will contain incomplete information
-/// and must not be used.
-static bool handleCalleesMD(const Instruction &I,
-                            SetVector<Function *> &Callees) {
-  auto *MD = I.getMetadata(LLVMContext::MD_callees);
-  if (!MD)
-    return false;
-
-  for (const auto &Op : MD->operands()) {
-    Function *Callee = mdconst::extract_or_null<Function>(Op);
-    if (!Callee)
-      return false;
-    Callees.insert(Callee);
-  }
-
-  return true;
-}
-
 void SplitGraph::buildGraph(CallGraph &CG) {
   SplitModuleTimer SMT("buildGraph", "graph construction");
   LLVM_DEBUG(
@@ -542,38 +519,28 @@ void SplitGraph::buildGraph(CallGraph &CG) {
                  Fn.printAsOperand(dbgs());
                  dbgs() << " - analyzing function\n");
 
-      SetVector<Function *> KnownCallees;
-      bool HasUnknownIndirectCall = false;
+      bool HasIndirectCall = false;
       for (const auto &Inst : instructions(Fn)) {
         // look at all calls without a direct callee.
-        const auto *CB = dyn_cast<CallBase>(&Inst);
-        if (!CB || CB->getCalledFunction())
-          continue;
-
-        // inline assembly can be ignored, unless InlineAsmIsIndirectCall is
-        // true.
-        if (CB->isInlineAsm()) {
-          LLVM_DEBUG(dbgs() << "    found inline assembly\n");
-          continue;
-        }
-
-        if (handleCalleesMD(Inst, KnownCallees))
-          continue;
-        // If we failed to parse any !callees MD, or some was missing,
-        // the entire KnownCallees list is now unreliable.
-        KnownCallees.clear();
+        if (const auto *CB = dyn_cast<CallBase>(&Inst);
+            CB && !CB->getCalledFunction()) {
+          // inline assembly can be ignored, unless InlineAsmIsIndirectCall is
+          // true.
+          if (CB->isInlineAsm()) {
+            LLVM_DEBUG(dbgs() << "    found inline assembly\n");
+            continue;
+          }
 
-        // Everything else is handled conservatively. If we fall into the
-        // conservative case don't bother analyzing further.
-        HasUnknownIndirectCall = true;
-        break;
+          // everything else is handled conservatively.
+          HasIndirectCall = true;
+          break;
+        }
       }
 
-      if (HasUnknownIndirectCall) {
+      if (HasIndirectCall) {
         LLVM_DEBUG(dbgs() << "    indirect call found\n");
         FnsWithIndirectCalls.push_back(&Fn);
-      } else if (!KnownCallees.empty())
-        DirectCallees.insert(KnownCallees.begin(), KnownCallees.end());
+      }
     }
 
     Node &N = getNode(Cache, Fn);