On 03/02/2015 09:55 AM, Richard Henderson wrote:
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)?
I think Jakub mentioned we needed it, otherwise we needed to check for a division by zero for the INTVAL. But I could be misunderstanding.
Aldy
