[LLVMdev] weird issue with mem2reg, still

Wed Jun 23 16:52:02 PDT 2004

 void MetaSplit::handleProgramUses(Value *V){
  if(!isa<BasicBlock>(V))
   programValues.insert(V);
  if(User *U = dyn_cast<User>(V)){
   User::op_iterator OB = U->op_begin(), OE = U->op_end();
   for(; OB != OE; ++OB){
    if(CallInst *CI = dyn_cast<CallInst>(*OB)){
      Function *F = CI->getCalledFunction();
      if(F == ii || F == fi || F == vi || F == di || F == ci || F == si){
       std::cerr << "This Call: " << *CI << std::endl;
       std::cerr << "\tNum Operands: " << CI->getNumOperands() << std::endl;
       handleGeneratorUses(CI->getOperand(1));
      }
    }
    else if(!(*programValues.find(*OB))){
     handleProgramUses(*OB);
    }
   }
  }
 }

pmeredit|zion|/localhome/pmeredit/llvm/projects/MetaSplit/lib/MetaSplit|[189
]% opt -load ../Debug/libmetasplit.so -mem2reg -metasplit < test3.s.bc >
m2r.bc
This Call:      %tmp.10 = call int %_Z1Ii( int %i.0 )           ; <int>
[#uses=1]

        Num Operands: 2
Segmentation fault (core dumped)

bugpoint...
*** Attempting to perform final cleanups: This Call:    %tmp.13 = call int
%_Z1Ii( )            ; <int> [#uses=1]

        Num Operands: 1
bugpoint: /home/vadve/lattner/cvs/llvm/include/llvm/User.h:35: llvm::Value*
llvm::User::getOperand(unsigned int): Assertion `i < Operands.size() &&
"getOperand() out of range!"' failed.

Now this is really strange, because it seems that the bugpoint function
differs from what is there on the normal run.  Also, a call to int %_Z1Ii
must ALWAYS have an interger argument (it's prototype is
int(int)), which aparently is no longer there (in the bugpoint version).

By far the best thing is I inserted an if that was if(numOperands > 1)
perform get operand call and this assert still happens.

----- Original Message ----- 
From: "Chris Lattner" <sabre at nondot.org>
To: <llvmdev at cs.uiuc.edu>
Sent: Wednesday, June 23, 2004 4:46 PM
Subject: Re: [LLVMdev] weird issue with mem2reg, still

> On Wed, 23 Jun 2004, Patrick Meredith wrote:
>
> > Somehow it fails with operand out of bounds when the number of operands
> > is 2 and I am asking for the second operand. Second meaning operand 1.
>
> Okay, so you have something like this:
>
>   if (CallInst *CI = dyn_cast<CallInst>(...)) {
>
>      ... = CI->getOperand(1);
>   }
>
> Can you send in this snippet of code, the assertion, and the results of:
>   std::cerr << "TheCall: " << *CI;
>
> executed right before the getOperand call that is failing?
>
> -Chris
>
>
> > ----- Original Message -----
> > From: "Chris Lattner" <sabre at nondot.org>
> > To: <llvmdev at cs.uiuc.edu>
> > Sent: Wednesday, June 23, 2004 4:24 PM
> > Subject: Re: [LLVMdev] weird issue with mem2reg, should have guessed
> >
> >
> > > On Wed, 23 Jun 2004, Patrick Meredith wrote:
> > >
> > > > What's different about code that's been mem2reg'd from straight
front
> > end
> > > > code, or anything that mem2reg hasn't been run on?  PHINODES!
> > >
> > > Yup, front-ends generally don't produce SSA form. :)
> > >
> > > > It appears to be crashing when I try to cast a Value* that's really
a
> > > > BB* (from the PHInode operands) to a User*, insteresting since I am
> > > > dyn_casting.  I just caught this on cerr though (printing out what
the
> > > > Value* was each time).
> > >
> > > Yeah, you shouldn't do that. :)  Also, you should use the 'cast'
template
> > > instead of the dyn_cast template unless you are prepared to handle the
> > > null return value.  Use 'cast' when you _know_ that something is a
> > > particular type.  This will give you a nice assertion failure instead
of a
> > > segfault when you deref the null pointer :)
> > >
> > > > Let me check bugpoint.
> > >
> > > Cool, post the testcase it produces.  Hopefully it will be small :)
> > >
> > > -Chris
> > >
> > > > ----- Original Message -----
> > > > From: "Misha Brukman" <brukman at uiuc.edu>
> > > > To: <llvmdev at cs.uiuc.edu>
> > > > Sent: Wednesday, June 23, 2004 3:56 PM
> > > > Subject: Re: [LLVMdev] weird issue with mem2reg
> > > >
> > > >
> > > > > On Wed, Jun 23, 2004 at 03:50:09PM -0500, Patrick Meredith wrote:
> > > > > > MetaSplit is an anlysis I just finished writing.  It doesn't
alter
> > > > > > anything, all it does is build a set of "program instructions".
For
> > > > > > some reason even though if I run it with any other combination
of
> > > > > > passes I've found, anytime I run it with mem2reg I get a seg
fault
> > in
> > > > > > dyn_cast!  Here's output:
> > > > >
> > > > > Since the crash is after your code is entered, the problem is
probably
> > > > > not in mem2reg, but in your pass.  To see if that's the case, you
can
> > do
> > > > > this:
> > > > >
> > > > > % opt -mem2reg < orig.bc > m2r.bc
> > > > > % opt -load=... -metasplit < m2r.bc > output.bc
> > > > >
> > > > > And see if it crashes in mem2reg or in your pass.  To narrow your
> > > > > testcase down further, we recommend the use of bugpoint, the
automatic
> > > > > test case reducer:
> > > > >
> > > > >   http://llvm.cs.uiuc.edu/docs/HowToSubmitABug.html
> > > > >
> > > > > In this case, this should work:
> > > > >
> > > > > % bugpoint -load=... -mem2reg -metasplit orig.bc
> > > > >
> > > > > --
> > > > > Misha Brukman :: http://misha.brukman.net ::
http://llvm.cs.uiuc.edu
> > > > >
> > > > > _______________________________________________
> > > > > LLVM Developers mailing list
> > > > > LLVMdev at cs.uiuc.edu         http://llvm.cs.uiuc.edu
> > > > > http://mail.cs.uiuc.edu/mailman/listinfo/llvmdev
> > > >
> > > > _______________________________________________
> > > > LLVM Developers mailing list
> > > > LLVMdev at cs.uiuc.edu         http://llvm.cs.uiuc.edu
> > > > http://mail.cs.uiuc.edu/mailman/listinfo/llvmdev
> > > >
> > >
> > > -Chris
> > >
> > > --
> > > http://llvm.cs.uiuc.edu/
> > > http://www.nondot.org/~sabre/Projects/
> > >
> > > _______________________________________________
> > > LLVM Developers mailing list
> > > LLVMdev at cs.uiuc.edu         http://llvm.cs.uiuc.edu
> > > http://mail.cs.uiuc.edu/mailman/listinfo/llvmdev
> >
> > _______________________________________________
> > LLVM Developers mailing list
> > LLVMdev at cs.uiuc.edu         http://llvm.cs.uiuc.edu
> > http://mail.cs.uiuc.edu/mailman/listinfo/llvmdev
> >
>
> -Chris
>
> -- 
> http://llvm.cs.uiuc.edu/
> http://www.nondot.org/~sabre/Projects/
>
> _______________________________________________
> LLVM Developers mailing list
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