[Bug c++/97580] New: reinterpret_cast<> and constant expression

[wolfgang.roehrl@gi-de.com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=97580

            Bug ID: 97580
           Summary: reinterpret_cast<> and constant expression
           Product: gcc
           Version: 7.5.0
            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 7.5.0.

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

Invokation line for the GNU C++ compiler:

ccppc -c -x c++ --std=gnu++17 -Wall -Werror -g -mcpu=e6500 -m32
      -maltivec -mvrsave -ftls-model=local-exec -msdata=sysv
      -fno-common -fno-openmp -mbig -mmultiple -mno-string -misel
      -mstrict-align -fverbose-asm -G 8 -O3
      -I<some include paths>
      -D<some #define's>
      X.CPP -oX.O


// file X.CPP

using T_PTR_FUNC = void (*)(int*);

void func1 (int*);
void func2 (float*);

constexpr T_PTR_FUNC arrFuncs[] =
{ func1, reinterpret_cast<T_PTR_FUNC>(func2) };


The compiler accepts this code even though a reinterpret_cast<> fails to be
a constant expression (cf. C++17 standard, 8.20/2).

With kind regards
W. Roehrl