[Bug rtl-optimization/55346] var-tracking generates incomplete/inaccurate debug info

[jakub at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=55346

Jakub Jelinek <jakub at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |jakub at gcc dot gnu.org

--- Comment #2 from Jakub Jelinek <jakub at gcc dot gnu.org> 2012-11-15 21:42:34 UTC ---
Which gcc version exactly (svn rev or date) you were using?
I can't reproduce this on x86_64-linux with current trunk and -g -O2.
 <2><68>: Abbrev Number: 4 (DW_TAG_variable)
    <69>   DW_AT_name        : (indirect string, offset: 0x74): argno
    <6d>   DW_AT_decl_file   : 1
    <6e>   DW_AT_decl_line   : 4
    <6f>   DW_AT_type        : <0x124>
    <73>   DW_AT_location    : 0x98(location list)
...
    00000098 0000000000400420 0000000000400437 (DW_OP_lit1; DW_OP_stack_value)
    00000098 0000000000400437 0000000000400483 (DW_OP_reg3 (rbx))
    00000098 0000000000400483 0000000000400488 (DW_OP_breg3 (rbx): -1;
DW_OP_stack_value)
    00000098 0000000000400488 0000000000400491 (DW_OP_reg3 (rbx))
    00000098 000000000040049f 00000000004004cc (DW_OP_reg3 (rbx))
    00000098 <End of list>

The only gap in there is in between 491 and 49f, and that is the epilogue:
  400491:       0f 1f 80 00 00 00 00    nopl   0x0(%rax)
  400498:       5b                      pop    %rbx
  400499:       5d                      pop    %rbp
  40049a:       31 c0                   xor    %eax,%eax
  40049c:       41 5c                   pop    %r12
  40049e:       c3                      retq   
  40049f:       90                      nop

I can reproduce it with r192900 though, so I bet this is a dup of PR54693
(which after all was your testcase).