On 02/26/2015 05:46 PM, Aldy Hernandez wrote:
> +;; Optimize division or modulo by constant power of 2, if the constant
> +;; materializes only after expansion.
> +(define_insn_and_split "*udivmod<mode>4_pow2"
> + [(set (match_operand:SWI48 0 "register_operand" "=r")
> + (udiv:SWI48 (match_operand:SWI48 2 "register_operand" "0")
> + (match_operand:SWI48 3 "const_int_operand" "n")))
> + (set (match_operand:SWI48 1 "register_operand" "=r")
> + (umod:SWI48 (match_dup 2) (match_dup 3)))
> + (clobber (reg:CC FLAGS_REG))]
> + "UINTVAL (operands[3]) - 2 < <MODE_SIZE> * BITS_PER_UNIT
> + && (UINTVAL (operands[3]) & (UINTVAL (operands[3]) - 1)) == 0"
> + "#"
> + "reload_completed"
> + [(set (match_dup 1) (match_dup 2))
> + (parallel [(set (match_dup 0) (lshiftrt:<MODE> (match_dup 2) (match_dup
> 4)))
> + (clobber (reg:CC FLAGS_REG))])
> + (parallel [(set (match_dup 1) (and:<MODE> (match_dup 1) (match_dup 5)))
> + (clobber (reg:CC FLAGS_REG))])]
> +{
Do you actually need the reload completed? Couldn't this be legitimately split
before reload (and then parts of it DCE'd as necessary)?
Otherwise, the split condition does need "&&" as mentioned by Uros.
r~
