[Bug target/48142] New: miscompilation with -mpreferred-stack-boundary=5 -fstack-check=specific

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

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=48142

           Summary: miscompilation with -mpreferred-stack-boundary=5
                    -fstack-check=specific
           Product: gcc
           Version: 4.7.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: target
        AssignedTo: unassigned@gcc.gnu.org
        ReportedBy: zsojka@seznam.cz
              Host: x86_64-pc-linux-gnu
            Target: x86_64-pc-linux-gnu


Created attachment 23674
  --> http://gcc.gnu.org/bugzilla/attachment.cgi?id=23674
reduced testcase

Output:
$ g++ -Os -mpreferred-stack-boundary=5 -fstack-check=specific
-fno-omit-frame-pointer testcase.C
$ valgrind -q ./a.out 
==16640== Invalid read of size 8
==16640==    at 0x4007D0: main (testcase.C:6)
==16640==  Address 0xfffffffffffffff8 is not stack'd, malloc'd or (recently)
free'd

(gdb) i r rsp
rsp            0xfffffffffffffff8       0xfffffffffffffff8
(gdb) disassemble
   0x00000000004007c6 <+82>:    pop    %rcx
   0x00000000004007c7 <+83>:    pop    %r10
   0x00000000004007c9 <+85>:    xor    %eax,%eax
   0x00000000004007cb <+87>:    pop    %rbp
   0x00000000004007cc <+88>:    lea    -0x8(%r10),%rsp
=> 0x00000000004007d0 <+92>:    retq   
End of assembler dump.

Tested revisions:
r171001 - fail
4.6 r170955 - fail
4.5 r170955 - OK