[Bug c++/102514] New: The allocation function shall not be called when existing an erroneous expression in noptr-new-declarator

[Bug c++/102514] New: The allocation function shall not be called when existing an erroneous expression in noptr-new-declarator

[xmh970252187 at gmail dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=102514

            Bug ID: 102514
           Summary: The allocation function shall not be called when
                    existing an erroneous expression in
                    noptr-new-declarator
           Product: gcc
           Version: 12.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: c++
          Assignee: unassigned at gcc dot gnu.org
          Reporter: xmh970252187 at gmail dot com
  Target Milestone: ---

````
struct C{
    void* operator new[](std::size_t N) noexcept(false){  // #1
        std::cout<<"abc\n";
        auto p =  malloc(10);
        return p;
    }
};
int n = -1;
auto ptr = new C[n];
std::cout<< ptr;
delete [] ptr;
````

GCC prints that `#1` is called and the address is non-null. According to
[expr.new] p9, the function at `#1` shall not be called, and since the function
has potential throwing specification, the new-expression should terminate by
throwing an exception.  

Example 2: 
````cpp
struct C2{
    void* operator new[](std::size_t N) noexcept{  // #2
        std::cout<<"abc\n";
        auto p =  malloc(10);
        return p;
    }
};
int n = -1;
auto ptr = new C2[n];
std::cout<< ptr;
delete [] ptr;
````
GCC calls `#2`, and the address is non-null.

[Bug c++/102514] The allocation function shall not be called when existing an erroneous expression in noptr-new-declarator

[pinskia at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=102514

--- Comment #1 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
Hmm, clang, GCC, ICC and MSVC all have the same behavior for the testcase.

[Bug c++/102514] The allocation function shall not be called when existing an erroneous expression in noptr-new-declarator

[xmh970252187 at gmail dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=102514

--- Comment #2 from jim x <xmh970252187 at gmail dot com> ---
It seems that they all do not obey [expr.new] p9, which says that

If the expression in a noptr-new-declarator is present, it is implicitly
converted to std​::​size_­t. The expression is erroneous if:

- the expression is of non-class type and its value before converting to
std​::​size_­t is less than zero;

- [...]

If the expression is erroneous after converting to std​::​size_­t: 

- if the expression is a core constant expression, the program is ill-formed; 

- otherwise, an allocation function is not called; instead

  - if the allocation function that would have been called has a non-throwing 
    exception specification ([except.spec]), the value of the new-expression is 
    the null pointer value of the required result type;  

  - otherwise, the new-expression terminates by throwing an exception of a type 
    that would match a handler ([except.handle]) of type
std​::​bad_­array_­new_­ 
    length.

[Bug c++/102514] The allocation function shall not be called when existing an erroneous expression in noptr-new-declarator

[redi at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=102514

Jonathan Wakely <redi at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
           See Also|                            |https://gcc.gnu.org/bugzill
                   |                            |a/show_bug.cgi?id=99934
         Resolution|---                         |DUPLICATE
             Status|UNCONFIRMED                 |RESOLVED

--- Comment #3 from Jonathan Wakely <redi at gcc dot gnu.org> ---
This is Bug 99934

*** This bug has been marked as a duplicate of bug 99934 ***