[NFC][FunctionAttrs] Remove duplication in old/new PM pipeline

This patch just extract code into a separate function to remove some
duplication between the old and new pass manager pipeline. Due to the
different CGSCC iterators used, not all code duplication was eliminated.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@338585 91177308-0d34-0410-b5e6-96231b3b80d8

Author: Johannes Doerfert

lib/Transforms/IPO/FunctionAttrs.cpp

@@ -1286,6 +1286,31 @@ static bool addNoRecurseAttrs(const SCCNodeSet &SCCNodes) {
   return setDoesNotRecurse(*F);
 }
 
+template <typename AARGetterT>
+static bool deriveAttrsInPostOrder(SCCNodeSet &SCCNodes, AARGetterT &&AARGetter,
+                                   bool HasUnknownCall) {
+  bool Changed = false;
+
+  // Bail if the SCC only contains optnone functions.
+  if (SCCNodes.empty())
+    return Changed;
+
+  Changed |= addArgumentReturnedAttrs(SCCNodes);
+  Changed |= addReadAttrs(SCCNodes, AARGetter);
+  Changed |= addArgumentAttrs(SCCNodes);
+
+  // If we have no external nodes participating in the SCC, we can deduce some
+  // more precise attributes as well.
+  if (!HasUnknownCall) {
+    Changed |= addNoAliasAttrs(SCCNodes);
+    Changed |= addNonNullAttrs(SCCNodes);
+    Changed |= inferAttrsFromFunctionBodies(SCCNodes);
+    Changed |= addNoRecurseAttrs(SCCNodes);
+  }
+
+  return Changed;
+}
+
 PreservedAnalyses PostOrderFunctionAttrsPass::run(LazyCallGraph::SCC &C,
                                                   CGSCCAnalysisManager &AM,
                                                   LazyCallGraph &CG,
@@ -1328,21 +1353,10 @@ PreservedAnalyses PostOrderFunctionAttrsPass::run(LazyCallGraph::SCC &C,
     SCCNodes.insert(&F);
   }
 
-  bool Changed = false;
-  Changed |= addArgumentReturnedAttrs(SCCNodes);
-  Changed |= addReadAttrs(SCCNodes, AARGetter);
-  Changed |= addArgumentAttrs(SCCNodes);
-
-  // If we have no external nodes participating in the SCC, we can deduce some
-  // more precise attributes as well.
-  if (!HasUnknownCall) {
-    Changed |= addNoAliasAttrs(SCCNodes);
-    Changed |= addNonNullAttrs(SCCNodes);
-    Changed |= inferAttrsFromFunctionBodies(SCCNodes);
-    Changed |= addNoRecurseAttrs(SCCNodes);
-  }
+  if (deriveAttrsInPostOrder(SCCNodes, AARGetter, HasUnknownCall))
+    return PreservedAnalyses::none();
 
-  return Changed ? PreservedAnalyses::none() : PreservedAnalyses::all();
+  return PreservedAnalyses::all();
 }
 
 namespace {
@@ -1382,7 +1396,6 @@ Pass *llvm::createPostOrderFunctionAttrsLegacyPass() {
 
 template <typename AARGetterT>
 static bool runImpl(CallGraphSCC &SCC, AARGetterT AARGetter) {
-  bool Changed = false;
 
   // Fill SCCNodes with the elements of the SCC. Used for quickly looking up
   // whether a given CallGraphNode is in this SCC. Also track whether there are
@@ -1403,24 +1416,7 @@ static bool runImpl(CallGraphSCC &SCC, AARGetterT AARGetter) {
     SCCNodes.insert(F);
   }
 
-  // Skip it if the SCC only contains optnone functions.
-  if (SCCNodes.empty())
-    return Changed;
-
-  Changed |= addArgumentReturnedAttrs(SCCNodes);
-  Changed |= addReadAttrs(SCCNodes, AARGetter);
-  Changed |= addArgumentAttrs(SCCNodes);
-
-  // If we have no external nodes participating in the SCC, we can deduce some
-  // more precise attributes as well.
-  if (!ExternalNode) {
-    Changed |= addNoAliasAttrs(SCCNodes);
-    Changed |= addNonNullAttrs(SCCNodes);
-    Changed |= inferAttrsFromFunctionBodies(SCCNodes);
-    Changed |= addNoRecurseAttrs(SCCNodes);
-  }
-
-  return Changed;
+  return deriveAttrsInPostOrder(SCCNodes, AARGetter, ExternalNode);
 }
 
 bool PostOrderFunctionAttrsLegacyPass::runOnSCC(CallGraphSCC &SCC) {