> On 12 Oct 2023, at 19:52, Andres Freund <and...@anarazel.de> wrote: > On 2023-10-12 13:24:27 +0300, Heikki Linnakangas wrote: >> On 12/10/2023 12:48, Daniel Gustafsson wrote:
>>> The attached patch adds special-case expression steps for common sets of >>> steps >>> in the executor to shave a few cycles off during execution, and make the JIT >>> generated code simpler. >>> >>> * Adds EEOP_FUNCEXPR_STRICT_1 and EEOP_FUNCEXPR_STRICT_2 for function calls >>> of >>> strict functions with 1 or 2 arguments (EEOP_FUNCEXPR_STRICT remains used >>> for >>>> 2 arguments). >>> * Adds EEOP_AGG_STRICT_INPUT_CHECK_ARGS_1 which is a special case for the >>> common case of one arg aggs. >> >> Are these relevant when JITting? I'm a little sad if the JIT compiler cannot >> unroll these on its own. Is there something we could do to hint it, so that >> it could treat the number of arguments as a constant? > > I think it's mainly important for interpreted execution. Agreed. >>> skip extra setup for steps which are only interested in the side effects. >> >> I'm a little surprised if this makes a measurable performance difference, >> but sure, why not. It seems nice to be more explicit when you don't expect a >> return value. Right, performance benefits aside it does improve readability IMHO. > IIRC this is more interesting for JIT than the above, because it allows LLVM > to know that the return value isn't needed and thus doesn't need to be > computed. Correct, this is important to the JIT code which no longer has to perform two Loads and one Store in order to get nothing, but can instead fastpath to building a zero returnvalue. -- Daniel Gustafsson
