[Bug libstdc++/78530] New: std::copy of volatile array triggers invalid conversion error

[poganoe at mail dot ru]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=78530

            Bug ID: 78530
           Summary: std::copy of volatile array triggers invalid
                    conversion error
           Product: gcc
           Version: 5.4.1
            Status: UNCONFIRMED
          Keywords: wrong-code
          Severity: normal
          Priority: P3
         Component: libstdc++
          Assignee: unassigned at gcc dot gnu.org
          Reporter: poganoe at mail dot ru
  Target Milestone: ---

I'm using arm-none-eabi-g++.exe (GNU Tools for ARM Embedded Processors) 5.4.1
20160919 (release) [ARM/embedded-5-branch revision 240496] for Windows. As far
as I know it's the latest version of arm-none-eabi target.

I'm trying to compile this:

#include <algorithm>

volatile uint8_t buf[10];
volatile uint8_t dest[10];

int main(void)
{
    std::copy(buf, buf+5, dest);
    return 0;
}

And I get:

arm-none-eabi\include\c++\5.4.1\bits\stl_algobase.h:384:23: error: invalid
conversion from 'volatile void*' to 'void*' [-fpermissive]
      __builtin_memmove(__result, __first, sizeof(_Tp) * _Num);
                       ^
<built-in>: note:   initializing argument 1 of 'void* __builtin_memmove(void*,
const void*, unsigned int)'
arm-none-eabi\include\c++\5.4.1\bits\stl_algobase.h:384:23: error: invalid
conversion from 'const volatile void*' to 'const void*' [-fpermissive]
<built-in>: note:   initializing argument 2 of 'void* __builtin_memmove(void*,
const void*, unsigned int)'

I'm not sure if it's correct behaviour but it certainly doesn't seem like it.
It should be possible to copy one array to the other array of the same type.