On 07/20/2016 06:39 PM, James Greenhalgh wrote:
On Wed, Jul 20, 2016 at 01:41:39PM +0200, Bernd Schmidt wrote:
How about wrapping the param value into COSTS_N_INSNS, to make the
value of the param less dependent on compiler internals?
I did consider this, but found it hard to word for the user documentation.
I found it easier to understand when it was in the same units as
rtx_cost, particularly as the AArch64 backend prints RTX costs to most
dump files (including ce1, ce2, ce3) so comparing directly was easy for me
to grok. I think going in either direction has the potential to confuse
users, the cost metrics of the RTL passes are very tightly coupled to
compiler internals.
I don't have a strong feeling either way, just a slight preference to keep
everything in the same units as rtx_cost where I can.
I guess it's ok.
Bernd
