Quoting Richard Guenther <richard.guent...@gmail.com>:
I think that needs to be documented somewhere in the internals manual,
I suppose it should logically go to the current end of the Output
Statement node in md.texi . Line 668 in revision 191429, just before
the Predicates
node.
possibly with an example.
AFAICT the existing examples are pieces of real machine descriptions.
One possibility would be the movsi_insn from the arc-4_4-20090909-branch:
(define_insn "*movsi_insn"
[(set (match_operand:SI 0 "move_dest_operand" "=Rcq,Rcq#q,w, w,w,
w,???w, ?w, w,Rcq#q, w,Rcq, S,Us<,RcqRck,!*x,r,m,???m,VUsc")
(match_operand:SI 1 "move_src_operand" "
cL,cP,Rcq#q,cL,I,Crr,?Rac,Cpc,Clb,?Cal,?Cal,T,Rcq,RcqRck,Us>,Usd,m,c,?Rac,C32"))]
"register_operand (operands[0], SImode)
|| register_operand (operands[1], SImode)
|| (CONSTANT_P (operands[1])
/* Don't use a LIMM that we could load with a single insn - we loose
delay-slot filling opportunities. */
&& !satisfies_constraint_I (operands[1])
&& satisfies_constraint_Usc (operands[0]))"
"@
mov%? %0,%1%&
mov%? %0,%1%&
mov%? %0,%1%&
mov%? %0,%1
mov%? %0,%1
ror %0,((%1*2+1) & 0x3f)
mov%? %0,%1
add %0,%S1
* return arc_get_unalign () ? \"add %0,pcl,%1-.+2\" : \"add %0,pcl,%1-.\";
mov%? %0,%S1%&
mov%? %0,%S1
ld%? %0,%1%&
st%? %1,%0%&
* return arc_short_long (insn, \"push%? %1%&\", \"st%U0 %1,%0%&\");
* return arc_short_long (insn, \"pop%? %0%&\", \"ld%U1 %0,%1%&\");
ld%? %0,%1%&
ld%U1%V1 %0,%1
st%U0%V0 %1,%0
st%U0%V0 %1,%0
st%U0%V0 %S1,%0"
[(set_attr "type"
"move,move,move,move,move,two_cycle_core,move,binary,binary,move,move,load,store,store,load,load,load,store,store,store")
(set_attr "iscompact"
"maybe,maybe,maybe,false,false,false,false,false,false,maybe_limm,false,true,true,true,true,true,false,false,false,false")
; Use default length for iscompact to mark length varying. But set length
; of Crr to 4.
(set_attr "length" "*,*,*,4,4,4,4,8,8,*,8,*,*,*,*,*,*,*,*,8")
(set_attr "cond"
"canuse,canuse_limm,canuse,canuse,canuse_limm,canuse_limm,canuse,nocond,nocond,canuse,canuse,nocond,nocond,nocond,nocond,nocond,nocond,nocond,nocond,nocond")])
Although the number of different concepts combined here might a bit
distract from the point. Also, it'll need steering commitee approval
to put this code, which was previously contributed under the GPL (on the
branch) into GFDL documentation.
Or should I make up a reduced/synthetic example for a simpler - but
probably pointless as an actual output template - example?
