[Bug c++/71372] [6/7 Regression] C++ FE drops TREE_THIS_VOLATILE in cp_fold on all tcc_reference trees

["hdusel at tangerine-soft dot de" <gcc-bugzilla at gcc dot gnu dot org>]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=71372

--- Comment #15 from Hans-Peter Dusel <hdusel@tangerine-soft.de> ---
(In reply to Jakub Jelinek from comment #12)
> Created attachment 38623 [details]
> gcc7-pr71372.patch
> 
> Patch I'm going to bootstrap/regtest.

Thanks guys!

I have applied this patch to official Release 6.1.0 too and want to confirm
that it will work for this too!

Now, the my example code will be compiled to correct code:

Thanks a lot! :-)

P.S: I'll attach the patch for gcc 6.1.0

+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++

// testmodule.cpp

void fpoke ()
{
  volatile unsigned short* FLASH = (volatile unsigned short*)0x20000000;

  *(FLASH + 0) = 0xAA;
  *(FLASH + 1) = 0x55;
  *(FLASH + 0) = 0xA0;
}


hdusel@Merlin /cygdrive/w/tmp
$ /opt/gcc-6.1.0-myos/bin/m68k-elf-g++ -O3 testmodule.cpp -c

hdusel@Merlin /cygdrive/w/tmp
$ /opt/gcc-6.1.0-myos/m68k-elf/bin/objdump.exe -d ./testmodule.o

./testmodule.o:     file format elf32-m68k


Disassembly of section .text:

00000000 <_Z5fpokePvsii>:
   0:   4e56 0000       linkw %fp,#0
   4:   207c 8000 0000  moveal #-2147483648,%a0
   a:   4e5e            unlk %fp
   c:   7055            moveq #85,%d0
   e:   30bc 00aa       movew #170,%a0@
  12:   33c0 8000 0002  movew %d0,80000002 <_Z5fpokePvsii+0x80000002>
  18:   30bc 00a0       movew #160,%a0@
  1c:   4e75            rts