[Bug target/69442] New: [6 Regression] wrong code with -Og and 64bit modulo @ armv7a

["zsojka at seznam dot cz" <gcc-bugzilla at gcc dot gnu dot org>]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=69442

            Bug ID: 69442
           Summary: [6 Regression] wrong code with -Og and 64bit modulo @
                    armv7a
           Product: gcc
           Version: 6.0
            Status: UNCONFIRMED
          Keywords: wrong-code
          Severity: normal
          Priority: P3
         Component: target
          Assignee: unassigned at gcc dot gnu.org
          Reporter: zsojka at seznam dot cz
  Target Milestone: ---
              Host: x86_64-pc-linux-gnu
            Target: armv7a-*-linux-gnueabi

Created attachment 37444
  --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=37444&action=edit
reduced testcase

Output:
$ armv7a-hardfloat-linux-gnueabi-gcc -v                    
Using built-in specs.
COLLECT_GCC=/repo/gcc-trunk/binary-latest-armv7a-hardfloat/bin/armv7a-hardfloat-linux-gnueabi-gcc
COLLECT_LTO_WRAPPER=/repo/gcc-trunk/binary-trunk-232760-checking-yes-rtl-df-nographite-armv7a-hardfloat/bin/../libexec/gcc/armv7a-hardfloat-linux-gnueabi/6.0.0/lto-wrapper
Target: armv7a-hardfloat-linux-gnueabi
Configured with: /repo/gcc-trunk//configure --enable-languages=c,c++
--enable-checking=yes,rtl,df --without-cloog --without-ppl --without-isl
--with-float=hard --with-arch=armv7-a --build=x86_64-pc-linux-gnu
--host=x86_64-pc-linux-gnu --target=armv7a-hardfloat-linux-gnueabi
--with-ld=/usr/bin/armv7a-hardfloat-linux-gnueabi-ld
--with-as=/usr/bin/armv7a-hardfloat-linux-gnueabi-as
--with-sysroot=/usr/armv7a-hardfloat-linux-gnueabi --disable-libstdcxx-pch
--prefix=/repo/gcc-trunk//binary-trunk-232760-checking-yes-rtl-df-nographite-armv7a-hardfloat
Thread model: posix
gcc version 6.0.0 20160123 (experimental) (GCC) 

$ armv7a-hardfloat-linux-gnueabi-gcc testcase.c -Og
$ qemu-arm ./a.out 
ffffffff0000ff19
qemu: uncaught target signal 6 (Aborted) - core dumped
Aborted

The expected output is "ffff0000ff19".

The .optimized dump looks fine.
The code generated by 5-branch and trunk is quite different; it is not obvious
for me where things go wrong.

Tested revisions:
trunk r232760 - FAIL
5-branch r232545 - OK
4_9-branch r232544 - OK
4_8-branch r224828 - OK