llvm dev - May 2009 - [LLVMdev] Pass Manager hangs with CallGraph and LoopSimplify

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");
}

See http://llvm.org/docs/GettingStarted.html#brokengcc and then try building
with something OTHER than GCC 4.1.2 .



----- Original Message ----
> From: Nick Johnson <npjohnso at cs.princeton.edu>
> To: LLVM Developers Mailing List <llvmdev at cs.uiuc.edu>
> Sent: Monday, May 11, 2009 3:01:12 PM
> Subject: [LLVMdev] Pass Manager hangs with CallGraph and LoopSimplify
> 
> 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");
> }
> _______________________________________________
> LLVM Developers mailing list
> LLVMdev at cs.uiuc.edu         http://llvm.cs.uiuc.edu
> http://lists.cs.uiuc.edu/mailman/listinfo/llvmdev

> See http://llvm.org/docs/GettingStarted.html#brokengcc and then try
building with something OTHER than GCC 4.1.2 .
I have confirmed this bug with GCC v 4.2.4, which is NOT on your list.

Nick

>
>
>
> ----- Original Message ----
>> From: Nick Johnson <npjohnso at cs.princeton.edu>
>> To: LLVM Developers Mailing List <llvmdev at cs.uiuc.edu>
>> Sent: Monday, May 11, 2009 3:01:12 PM
>> Subject: [LLVMdev] Pass Manager hangs with CallGraph and LoopSimplify
>>
>> 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");
>> }
>> _______________________________________________
>> LLVM Developers mailing list
>> LLVMdev at cs.uiuc.edu         http://llvm.cs.uiuc.edu
>> http://lists.cs.uiuc.edu/mailman/listinfo/llvmdev
>
>
>
>
> _______________________________________________
> LLVM Developers mailing list
> LLVMdev at cs.uiuc.edu         http://llvm.cs.uiuc.edu
> http://lists.cs.uiuc.edu/mailman/listinfo/llvmdev
>


-- 
Nick Johnson