[llvm-dev] Alias set with only one element having may-alias property

[Nema, Ashutosh via llvm-dev]

Looks like missing some basics here.

Consider following test:

     1  int escape(int **ptr);
     2  int foo(int * ptr)
     3  {
     4     return escape(&ptr);
     5  }

At line number 4 address of pointer passed to another routine.

When I print alias set:

Alias Set Tracker: 1 alias sets for 1 pointer values.
  AliasSet[0x43be490, 2] may alias, Mod/Ref   Pointers: (i32** %ptr.addr, 8)
    1 Unknown instructions: i32 %call

Here ptr.addr is only in the set, and set property is may-alias.

I'm not sure it may-alias with what, if its aliasing with self then why not must-alias ?

Is may-alias indicating ptr.addr is unsafe to optimize, and it can possibly alias with something.

Regards,
Ashutosh

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