On Tue, 28 Nov 2023, Jeff Law wrote:
> FWIW, I was looking at a regression with our internal tests after your
> changes. It was quite nice to see how well twiddling -mbranch-cost
> correlated to how many instructions we would allow in a conditional move
> sequence.
I'm a bit concerned though t
On 11/23/23 11:34, Maciej W. Rozycki wrote:
On Sun, 19 Nov 2023, Jeff Law wrote:
As I suspect you know a big part of the problem here is that BRANCH_COST and
rtx_cost don't have any common scale and thus trying to compare BRANCH_COST to
RTX_COST doesn't have well defined meaning.
We do h
On Sun, 19 Nov 2023, Jeff Law wrote:
> As I suspect you know a big part of the problem here is that BRANCH_COST and
> rtx_cost don't have any common scale and thus trying to compare BRANCH_COST to
> RTX_COST doesn't have well defined meaning.
We do have preexisting places using COSTS_N_INSNS (BR
On 11/18/23 22:36, Maciej W. Rozycki wrote:
The generic branch costing model for if-conversion assumes a fixed cost
of COSTS_N_INSNS (2) for a conditional branch, and that one half of that
cost comes from a preceding condition-set instruction, such as with
MODE_CC targets, and then the other h
The generic branch costing model for if-conversion assumes a fixed cost
of COSTS_N_INSNS (2) for a conditional branch, and that one half of that
cost comes from a preceding condition-set instruction, such as with
MODE_CC targets, and then the other half of that cost is for the actual
branch ins
