| From: | Andres Freund <andres(at)anarazel(dot)de> |
|---|---|
| To: | Pierre Ducroquet <p(dot)psql(at)pinaraf(dot)info> |
| Cc: | pgsql-hackers <pgsql-hackers(at)postgresql(dot)org> |
| Subject: | Re: llvmjit - improve code generated in O0 |
| Date: | 2026-02-10 20:43:19 |
| Message-ID: | aYuWox7qw06iDezd@alap3.anarazel.de |
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| Lists: | pgsql-hackers |
Hi,
On 2026-02-10 17:39:40 +0000, Pierre Ducroquet wrote:
> After spending some time looking at the assembly code generated by llvmjit
> for a simple query (SELECT * FROM demo WHERE a = 42), digging in the IR
> showed that by simply tweaking the IR one could push llvm into generating
> better code, kind of "for free", without having to spend time in the LLVM
> optimizer.
Yea, if that's simple enough to do, there's no reason to not do that.
I do think we eventually need a somewhat better "cheap" optimization
pipeline. But even if we had that, there's no reason to not just immediately
generate better code if it's cheap.
Do these changes still make a difference after adding simplifycfg as you
propose?
Greetings,
Andres Freund
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