Ok, I fixed it using using pair of define_insn and define_expand below:
(define_expand "addsi3"
[(set (match_operand:SI 0 "register_operand" "=r")
(plus:SI (match_operand:SI 1 "register_operand" "r")
(match_operand:SI 2 "nonmemory_operand" "")))]
""
{
if (CONST_INT_P (operands [2]))
{
if (can_create_pseudo_p ())
{
operands[2] = force_reg (SImode, operands[2]);
emit_insn (gen_rtx_SET (SImode, operands[0], gen_rtx_PLUS
(SImode, operands [1], operands [2])));
}
}
else
{
emit_insn (gen_rtx_SET (SImode, operands[0], gen_rtx_PLUS
(SImode, operands [1], operands [2])));
}
DONE;
})
(define_insn "*addsi3_internal"
[(set (match_operand:SI 0 "register_operand" "=r")
(plus:SI (match_operand:SI 1 "register_operand" "r")
(match_operand:SI 2 "register_operand" "r")))]
""
"l.radd \t%0,%1,%2"
[(set_attr "type" "add")
(set_attr "length" "1")])
I have to admit, that I don't understand why it works... I figured out
possible explanation. When define_expand doesn't emit any insns, but
it finishes with DONE, GCC tries other strategy to fir RTL instruction
to machine description, right?
I have also question about output assembly (compiled with -dP option).
Sample C code:
int b = 123;
int a = b + 998;
output:
#(insn 8 7 19 simple_test.c:4 (set (reg:SI 3 r3 [44])
# (const_int 998 [0x3e6])) 8 {*movsi_insn} (nil))
l.addi r3,r0,998 # move immediate I # 8 *movsi_insn/1 [length = 1]
#(insn 19 8 9 (set (reg:SI 3 r3 [44])
# (rto:SI (reg:SI 3 r3 [44]))) 72 {rto} (nil))
l.rto r3,r3 # 19 rto [length = 1]
#(insn 9 19 10 simple_test.c:4 (set:SI (reg:SI 3 r3 [43])
# (plus:SI (reg:SI 4 r4 [42])
# (reg:SI 3 r3 [44]))) 49 {*addsi3_internal}
(expr_list:REG_EQUAL (plus:SI (reg:SI 4 r4 [42])
# (const_int 998 [0x3e6]))
# (nil)))
l.radd r3,r4,r3 # 9 *addsi3_internal [length = 1]
What "(expr_list:REG_EQUAL (..." stays for?
