Hi, On Tue, 9 Jul 2013, David Given wrote:
> Trying 8, 9 -> 10: > Successfully matched this instruction: > (set (reg:SI 47 [ *_5 ]) > (mem:SI (plus:SI (mult:SI (reg/v:SI 43 [ b ]) > (const_int 4 [0x4])) > (reg:SI 0 r0 [ a ])) [2 *_5+0 S4 A32])) > rejecting combination of insns 8, 9 and 10 > original costs 8 + 4 + 4 = 16 > replacement cost 32 > > So, how is it calculating the cost of my instruction? Where's it getting > that 32 from (which seems weirdly high)? As you didn't adjust any cost I would guess the high value comes from the default implementation of address_cost, which simply uses arithmetic cost, and the MULT in there is quite expensive by default. See TARGET_ADDRESS_COST in several ports. Ciao, Michael.
