On Wed, Apr 14, 2021 at 09:20:35PM +0200, Jakub Jelinek wrote:
> The question is what to write in the splitter pattern so that
> they would match.
> [(set (match_operand:GPI 0 "register_operand")
> (LOGICAL:GPI
> (and:GPI (ashift:GPI (match_operator:GPI 4 "subreg_lowpart_operator"
> [(match_operand 1 "register_operand")])
> (match_operand:QI 2
> "aarch64_shift_imm_<mode>"))
> (match_operand:GPI 3 "const_int_operand"))
> (zero_extend:GPI (match_dup 1))))]
> provably doesn't (that is from the splitter I wrote for the non-hard regs),
> nor
> [(set (match_operand:GPI 0 "register_operand")
> (LOGICAL:GPI
> (and:GPI (ashift:GPI (match_operand:GPI 1 "register_operand")
> (match_operand:QI 2
> "aarch64_shift_imm_<mode>"))
> (match_operand:GPI 3 "const_int_operand"))
> (zero_extend:GPI (subreg (match_dup 1) 0))))]
> works (and it is unclear how I'd find out the mode of the subreg even if it
> worked).
What seems to work and handles both the pseudos (in which case there
is a (subreg:GPI (reg:whatever xyz) 0) and (reg:whatever xyz)
in the operands) and the hard registers (in which case there is
(reg:GPI xyz) and (reg:whatever xyz) in the operands) is:
(define_split
[(set (match_operand:GPI 0 "register_operand")
(LOGICAL:GPI
(and:GPI (ashift:GPI (match_operand:GPI 1 "register_operand")
(match_operand:QI 2 "aarch64_shift_imm_<mode>"))
(match_operand:GPI 3 "const_int_operand"))
(zero_extend:GPI (match_operand 4 "register_operand"))))]
"can_create_pseudo_p ()
&& ((paradoxical_subreg_p (operands[1])
&& rtx_equal_p (SUBREG_REG (operands[1]), operands[4]))
|| (REG_P (operands[1])
&& REG_P (operands[4])
&& REGNO (operands[1]) == REGNO (operands[4])))
&& (trunc_int_for_mode (GET_MODE_MASK (GET_MODE (operands[4]))
<< INTVAL (operands[2]), <MODE>mode)
== INTVAL (operands[3]))"
[(set (match_dup 5) (zero_extend:GPI (match_dup 4)))
(set (match_dup 0) (LOGICAL:GPI (ashift:GPI (match_dup 5) (match_dup 2))
(match_dup 5)))]
"operands[5] = gen_reg_rtx (<MODE>mode);"
)
While it is one pattern, it needs different handling for the two cases.
Is that acceptable?
Jakub
