instruction constraints

[Jesús Barba Romero]

Anyone can tell me what information is used when instruction constraints
are checked ? where is stored ? 
I have a RTL expresion that seems to be equeal to another valid one. I
supouse I've lost information but I don't know where.

If there is a web page or a manual about it.. thanks anyway.

The RTL expresion in question is:

hello.c:12: Unrecognizable insn:

(insn 12 10 13 (set (mem/f:SI (pre_dec:SI (reg:SI 7 esp)) 0)
        (symbol_ref:SI ("*.LC0"))) -1 (nil)
    (nil))
hello.c:12: Internal compiler error in extract_insn, at recog.c:2162
   Please submit a full bug report.
   See <URL: http://www.gnu.org/software/gcc/bugs.html > for
instructions.o.c:12: Unrecognizable insn:

Thanks ...
-- 
Jesús Barba Romero
jbr62357@alumnos.inf-cr.uclm.es
Universidad de Castilla-La Mancha
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