[LLVMdev] Pass Manager hangs with CallGraph and LoopSimplify

[Nick Johnson]

Hello,

I have discovered a situation in which the pass manager will infinite
loop.  The minimal test case is below this message.  The required
structure of these passes is;

Before requires CallGraph
After requires LoopSimplify and Before

I can observe this through opt:

opt -load ./libBug.so -after input.bc -o output.bc

I built my copy of llvm from svn revision 68820 using gcc 4.1.2

Any suggestions?
-- 
Nick Johnson




#include "llvm/Pass.h"
#include "llvm/Transforms/Scalar.h"
#include "llvm/Analysis/CallGraph.h"


using namespace llvm;

class Before : public ModulePass {
  public:
    static char ID;
    Before() : ModulePass(&ID) {}

    void getAnalysisUsage(AnalysisUsage &au) const {
      au.addRequired< CallGraph >();
      au.setPreservesAll();
    }

    bool runOnModule(Module &m) { return false; }
};

class After : public FunctionPass {
  public:
    static char ID;

    After() : FunctionPass(&ID) {}

    void getAnalysisUsage(AnalysisUsage &au) const {
      au.addRequiredID( LoopSimplifyID );
      au.addRequired< Before >();
      au.setPreservesAll();
    }

    bool runOnFunction(Function &f) { return false; }
};

char Before::ID = 0;
char After::ID = 0;
namespace {
  RegisterPass< Before > x("before", "before");
  RegisterPass< After > y("after", "after");
}