[Bug middle-end/59399] ICE in expand_expr_real_1 with -m64 -fsanitize=signed-integer-overflow

[pinskia at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=59399

--- Comment #4 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
(In reply to Marek Polacek from comment #3)
> Why get_rtx_for_ssa_name returns different rtx for the same SSA_NAME?

Because of the PROMOTE_MODE macro.  From docs:
/* Define this macro if it is advisable to hold scalars in registers
   in a wider mode than that declared by the program.  In such cases,
   the value is constrained to be within the bounds of the declared
   type, but kept valid in the wider mode.  The signedness of the
   extension may differ from that of the type.  */