http://gcc.gnu.org/bugzilla/show_bug.cgi?id=50762
--- Comment #20 from Uros Bizjak <ubizjak at gmail dot com> 2011-11-10 18:10:33 UTC --- (In reply to comment #17) > > However, it is rejected by the lea_address_operand predicate check > > due to its mode (VOIDmode != SImode). This is a bit odd because most > > standard predicates accept a CONST_INT no matter what mode is requested. > > This isn't only odd, this goes against the documentation: > > "Predicates written with `define_predicate' automatically include a > test that MODE is `VOIDmode', or OP has the same mode as MODE, or OP is > a `CONST_INT' or `CONST_DOUBLE'. They do _not_ check specifically for > integer `CONST_DOUBLE', nor do they test that the value of either kind > of constant fits in the requested mode." > > > Maybe one way to fix this would be to define lea_address_operand > > using define_special_predicate and then implement an appropriate > > mode check that handles CONST_INT by hand ... > > Clearly the oddity you pointed out above is counter-intuitive. It is present > in the original patch: http://gcc.gnu.org/ml/gcc-patches/2004-08/msg00663.html > > Maybe worth discussing on the main list in order to decide what needs to be > changed, the documentation or the implementation. The documentation is wrong, so following patch removes all the blurb about handling of constants. Index: doc/md.texi =================================================================== --- doc/md.texi (revision 181258) +++ doc/md.texi (working copy) @@ -1001,16 +1001,7 @@ Predicates written with @code{define_predicate} automatically include a test that @var{mode} is @code{VOIDmode}, or @var{op} has the same -mode as @var{mode}, or @var{op} is a @code{CONST_INT} or -@code{CONST_DOUBLE}. They do @emph{not} check specifically for -integer @code{CONST_DOUBLE}, nor do they test that the value of either -kind of constant fits in the requested mode. This is because -target-specific predicates that take constants usually have to do more -stringent value checks anyway. If you need the exact same treatment -of @code{CONST_INT} or @code{CONST_DOUBLE} that the generic predicates -provide, use a @code{MATCH_OPERAND} subexpression to call -@code{const_int_operand}, @code{const_double_operand}, or -@code{immediate_operand}. +mode as @var{mode}.
