Reapply r77654 with a fix: MachineFunctionPass's getAnalysisUsage

shouldn't do AU.setPreservesCFG(), because even though CodeGen passes
don't modify the LLVM IR CFG, they may modify the MachineFunction CFG,
and passes like MachineLoop are registered with isCFGOnly set to true.

llvm-svn: 77691

llvm/lib/CodeGen/MachineFunctionPass.cpp

@@ -0,0 +1,52 @@
+//===-- MachineFunctionPass.cpp -------------------------------------------===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+// This file contains the definitions of the MachineFunctionPass members.
+//
+//===----------------------------------------------------------------------===//
+
+#include "llvm/Analysis/AliasAnalysis.h"
+#include "llvm/Analysis/ScalarEvolution.h"
+#include "llvm/Analysis/IVUsers.h"
+#include "llvm/Analysis/LiveValues.h"
+#include "llvm/Analysis/LoopDependenceAnalysis.h"
+#include "llvm/Analysis/MemoryDependenceAnalysis.h"
+#include "llvm/CodeGen/MachineFunctionAnalysis.h"
+#include "llvm/CodeGen/MachineFunctionPass.h"
+using namespace llvm;
+
+bool MachineFunctionPass::runOnFunction(Function &F) {
+  // Do not codegen any 'available_externally' functions at all, they have
+  // definitions outside the translation unit.
+  if (F.hasAvailableExternallyLinkage())
+    return false;
+
+  MachineFunction &MF = getAnalysis<MachineFunctionAnalysis>().getMF();
+  return runOnMachineFunction(MF);
+}
+
+void MachineFunctionPass::getAnalysisUsage(AnalysisUsage &AU) const {
+  AU.addRequired<MachineFunctionAnalysis>();
+  AU.addPreserved<MachineFunctionAnalysis>();
+
+  // MachineFunctionPass preserves all LLVM IR passes, but there's no
+  // high-level way to express this. Instead, just list a bunch of
+  // passes explicitly.
+  AU.addPreserved<AliasAnalysis>();
+  AU.addPreserved<ScalarEvolution>();
+  AU.addPreserved<IVUsers>();
+  AU.addPreserved<LoopDependenceAnalysis>();
+  AU.addPreserved<MemoryDependenceAnalysis>();
+  AU.addPreserved<LiveValues>();
+  AU.addPreserved<DominatorTree>();
+  AU.addPreserved<DominanceFrontier>();
+  AU.addPreserved<LoopInfo>();
+
+  FunctionPass::getAnalysisUsage(AU);
+}