[LLVMdev] Pass Manager hangs with CallGraph and LoopSimplify

[Samuel Crow]

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");
> }
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