https://gcc.gnu.org/bugzilla/show_bug.cgi?id=115749
Hongtao Liu <liuhongt at gcc dot gnu.org> changed:
What |Removed |Added
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CC| |haochen.jiang at intel dot com,
| |liuhongt at gcc dot gnu.org
--- Comment #10 from Hongtao Liu <liuhongt at gcc dot gnu.org> ---
> One of the comments in PR 115756 was "I'd lean towards shift+add because for
> example Intel E-cores have a slow imul.". However, my benchmarks suggest
> that even on Intel Efficiency CPU cores the algorithm with 2 multiplication
> instructions is faster. (I used the Process Lasso tool on Windows 11 to
> force the benchmark to be run on an Efficiency CPU core).
@haocheng, could you try the benchmark on our Sierra Forest machine?
I'm ok to adjust rtx_cost of imulq for COST_N_INSNS (4) to COST_N_INSNS (3) if
the performance test looks ok.
