[Bug debug/46095] [4.6 Regression] ICE: in dwarf2out_frame_debug_expr, at dwarf2out.c:2341 with -fstack-protector

["jakub at gcc dot gnu.org" <gcc-bugzilla at gcc dot gnu dot org>]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=46095

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

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|NEW                         |ASSIGNED
         AssignedTo|unassigned at gcc dot       |jakub at gcc dot gnu.org
                   |gnu.org                     |

--- Comment #2 from Jakub Jelinek <jakub at gcc dot gnu.org> 2010-11-15 17:28:45 UTC ---
Created attachment 22402
  --> http://gcc.gnu.org/bugzilla/attachment.cgi?id=22402
gcc46-pr46095.patch

Untested fix.

The problem why the current code doesn't work is that scheduling swaps
the movq %rsp, %rbp and movabsq $......, %r11 insns.  When they are swapped,
it doesn't help that the %r11 setting insn is marked as frame related, it sets
cfa_temp, but the next insn (movq %rsp, %rbp) clobbers cfa_temp and thus when
on the following addq %r11, %rsp insn we'd like to be able to look up the
offset
loaded into r11, cfa_temp no longer describes it and thus we ICE.

Before Richard's patch the insn was using a const_int in the addition instead
and had additional USE on r11 register.  I'd say the easiest fix is just to
describe what the insn actually does in REG_FRAME_RELATED_EXPR, as done in this
patch.  Then what value is loaded into r11 is uninteresting.