On 3/25/24 2:57 PM, Palmer Dabbelt wrote:
On Mon, 25 Mar 2024 13:49:18 PDT (-0700), jeffreya...@gmail.com wrote:
On 3/25/24 2:31 PM, Palmer Dabbelt wrote:
On Mon, 25 Mar 2024 13:27:34 PDT (-0700), Jeff Law wrote:
I'd doubt it's worth the complexity. Picking some reasonable value
gets
you the vast majority of the benefit. Something like
COSTS_N_INSNS(6) is enough to get CSE to trigger. So what's left is a
reasonable cost, particularly for the division-by-constant case
where we
need a ceiling for synth_mult.
Ya, makes sense. I noticed our multi-word multiply costs are a bit odd
too (they really only work for 64-bit mul on 32-bit targets), but that's
probably not worth worrying about either.
We do have a changes locally that adjust various costs. One of which is
highpart multiply. One of the many things to start working through once
gcc-15 opens for development. Hence my desire to help keep gcc-14 on
track for an on-time release.
Cool. LMK if there's anything we can do to help on that front.
I think the RISC-V space is in pretty good shape. Most of the issues
left are either generic or hitting other targets. While the number of
P1s has been flat or rising, that's more an artifact of bug
triage/reprioritization process that's ongoing. I can only speak for
myself, but the progress in nailing down the slew of bugs thrown into
the P1 bucket over the last few weeks has been great IMHO.
jeff
