[LLVMdev] Pass Manager hangs with CallGraph and LoopSimplify

[Nick Johnson]

> 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");
>> }
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>
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-- 
Nick Johnson