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Re: Repost: RFA [4.1]: improvement to if-conversion and cross-jumping (PR20070)
Joern RENNECKE wrote:
I've just thought of another thing that won't work right with the
current infrastructure:
when we call validate_change, the change is installed instantly. Thus,
when we try to match
the same register again, we will fail. That is easy to fix for
PRE_MODIFY - just save the
register before doing the first potential change - but much harder when
you have a PARALLEL
where any SET_DEST could be a STRICT_LOW_PART, ZERO_EXTEND or SIGN_EXTEND.
I see four possible approaches here:
Maybe we could extend RVALUE to also describe the case that we have an
in-out operand, and the REG handling could be changed to handle this
case as well? Then we'd have to scan each part of the insn only once.
Bernd