[Bug c++/69769] New: arithmetic operation on pointer to a function

["wolfgang dot roehrl at gi-de dot com" <gcc-bugzilla at gcc dot gnu dot org>]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=69769

            Bug ID: 69769
           Summary: arithmetic operation on pointer to a function
           Product: gcc
           Version: 6.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: c++
          Assignee: unassigned at gcc dot gnu.org
          Reporter: wolfgang.roehrl@gi-de.com
  Target Milestone: ---

Hi,

I would like to post a bug report for the GNU C/C++ compiler 6.0.0.

We use the compiler to generate code for a PowerPC processor.

Invokation line for the GNU C++ compiler:

ccppc -c -x c++ -std=gnu++14 -Wall -Werror -g -mcpu=e6500 -m32
      -maltivec=be -mvrsave -ftls-model=local-exec -msdata=sysv
      -fno-common -fno-openmp -mbig -mmultiple -mno-string -misel
      -mstrict-align -fverbose-asm -fno-exceptions -fno-rtti
      -ftemplate-backtrace-limit=20 -G 8 -O3
      -I<some include paths>
      -D<some #define's>
      X.CPP -oX.O


// file X.CPP

#include "atomic"

typedef void (T_FUNC) (int);

T_FUNC* getFunc (std::atomic<T_FUNC*>& refPtr)
{
    return refPtr.fetch_add(0, std::memory_order_relaxed);
}


The compiler accepts this programm despite of performing an arithmetic
operation on pointer to a function.

I think this is not standard conforming. The C++11 standard, 29.6.5/28
describes the semantic of the atomic fetch functions:
"Atomically replaces the value pointed to [...] by this with the result of
the computation applied to the value pointed to [...] by this and the given
operand." But applying an arithmetic operation on pointer to a function is
not a legal computation.


With kind regards
W. Roehrl