On 4/13/25 10:50 PM, Keith Packard wrote:
pattern using rx_cmpstrn is cmpstrsi for which len is a constant -1,
so we'll be moving the setpsw instructions from rx_cmpstrn to
cmpstrnsi as follows:
1. Adjust the predicate on the length operand from "register_operand"
to "nonmemory_operand". This will allow constants to appear here,
instead of having them already transferred into a register.
2. Check to see if the len value is constant, and then check if it is
actually zero. In that case, short-circuit the rest of the pattern
and set the result register to 0.
3. Emit 'setpsw c' and 'setpsw z' instructions when the len is not a
constant, in case it turns out to be zero at runtime.
4. Remove the two 'setpsw' instructions from rx_cmpstrn.
Thanks. I made some minor stylistic adjustments and pushed the change
to the trunk. Thanks!
jeff
