On 4/3/25 7:40 AM, Richard Sandiford wrote:
But log-links on i2 are for uses in i2 for defs before i2, given
i0/i1/i2 changed/have gone away we adjust those to eventually end
up on insns between i2 and i3 (or indeed after i3). Combine then
want's to try combine the insns with changed log-links.
Right. But I meant in the case where i2 hasn't changed, which
I thought was the case in contention. If i2 hasn't changed then
its uses are the same, and so there is no need to distribute its
log links.
I'm not following closely (though I'm definitely interested as I
continue to see cases were 2->2 for rewriting would be profitable).
Do we have to worry about the case where i2 doesn't change, but the
other insn does change? I know I saw one of those scenarios in a hot
loop in coremark for rv64.
Jeff
