llvm dev - Aug 2014 - [LLVMdev] difference between replaceAllUsesWith and replaceUsesOfWith?

Why is the first for loop not equivalent to the second?

Thanks,
Rob

==========================
for (GlobalVariable **i = Globals.begin(), **e = Globals.end(); i != e;
++i) {
  GlobalVariable *GV = *i;

  Constant *GEP = ConstantExpr::getGetElementPtr(...);
  GV->replaceAllUsesWith(GEP);
}

==========================
for (GlobalVariable **i = Globals.begin(), **e = Globals.end(); i != e;
++i) {
  GlobalVariable *GV = *i;

  Constant *GEP = ConstantExpr::getGetElementPtr(...);

for (Value::use_iterator ui = GV->use_begin(); ui != GV->use_end(); ++ui)
{
  if(User *u = dyn_cast < User > (*ui)) {
    u->replaceUsesOfWith(GV, GEP);
  }
}

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Hi Rob,

On 9 August 2014 02:03, Rob Jansen <jansen at cs.umn.edu>
wrote:
> Why is the first for loop not equivalent to the second?
In the second loop, "*ui" is an llvm::Use object. It's owned by a
User, but isn't a subclass of one. To match the first loop, you either
need to call Value::user_begin instead of use_begin, or do the cast on
"ui->getUser()".

Cheers.

Tim.

On Sat, Aug 9, 2014 at 6:06 AM, Tim Northover <t.p.northover at gmail.com>
wrote:
> Hi Rob,
>
> On 9 August 2014 02:03, Rob Jansen <jansen at cs.umn.edu> wrote:
> > Why is the first for loop not equivalent to the second?
>
> In the second loop, "*ui" is an llvm::Use object. It's owned
by a
> User, but isn't a subclass of one. To match the first loop, you either
> need to call Value::user_begin instead of use_begin, or do the cast on
> "ui->getUser()".
>
I think this is incorrect since the use_iterator is defined as:

`typedef value_use_iterator<User> use_iterator;`

and indeed `ui->getUser();` is not a callable function on a User. What am I
missing?

-Rob
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