[Bug debug/64511] [5 Regression] ICE at -O3 with -g enabled on x86_64-linux-gnu

[rguenth at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=64511

Richard Biener <rguenth at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
           Keywords|                            |compile-time-hog,
                   |                            |memory-hog
             Status|ASSIGNED                    |NEW
           Assignee|rguenth at gcc dot gnu.org         |unassigned at gcc dot gnu.org

--- Comment #4 from Richard Biener <rguenth at gcc dot gnu.org> ---
Hmm, nothing I can do about and I can't spot real differences during RTL
expansion.  TER gobbles up the whole function though and maybe debug
expression expansion is slightly different (also due to operand
canonicalization).

I note that we don't fold x % x (to preserve the x == 0 exception), a missed
optimization opportunity is to do

  if (x == 0)
   __builtin_trap ();

at the very first point we encounter that (possibly during VRP if VRP
detects that it can simplify further expressions with x != 0 knowledge).

Note that this bug may be an effective dup of another one.