[Bug tree-optimization/26388] Variable sized storage allocation should be promoted to stack allocation

[msebor at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=26388

Martin Sebor <msebor at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|UNCONFIRMED                 |WAITING
   Last reconfirmed|                            |2017-02-16
                 CC|                            |msebor at gcc dot gnu.org
     Ever confirmed|0                           |1

--- Comment #10 from Martin Sebor <msebor at gcc dot gnu.org> ---
The implementation challenges aside, I think the transformation suggested here
could break some valid (if rare) C++ programs.  std::vector is specified to use
std::allocator to obtain storage which in turn is specified to use operator
new.  Operator new is a replaceable function meaning that a program can define
its own that keeps track of the number of calls to it by vector (and other)
member functions.  Such programs could break by GCC eliminating the of the
operator.

Richard, in light of this and other concerns in the discussion of this bug, do
you want to keep this bug open or do you agree with closing it?