Re: Add RISC-V Zbb popcount optimization

From: "Greg Burd" <greg(at)burd(dot)me>
To: "Tom Lane" <tgl(at)sss(dot)pgh(dot)pa(dot)us>
Cc: "Andres Freund" <andres(at)anarazel(dot)de>, "Nathan Bossart" <nathandbossart(at)gmail(dot)com>, "John Naylor" <johncnaylorls(at)gmail(dot)com>, pgsql-hackers <pgsql-hackers(at)postgresql(dot)org>, "Andrew Dunstan" <andrew(at)dunslane(dot)net>
Subject: Re: Add RISC-V Zbb popcount optimization
Date: 2026-05-29 17:26:34
Message-ID: 6470e83d-b1c9-4c19-863f-9c68fdff3331@app.fastmail.com
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On Fri, May 29, 2026, at 12:23 PM, Tom Lane wrote:
> "Greg Burd" <greg(at)burd(dot)me> writes:
>> The zic.c hit is the one that bothers me. It's the same shape as des_init() --
>> byte-sized destination, scatter store via an indexing array -- and it's not
>> exercised by `make check`, since zic runs at `make install` to compile the IANA
>> tz data.
>
> "make check" certainly *will* run zic.c, while creating the temporary
> installation. (Unless you use --with-system-tzdata, which I'm sure
> most production builds do.) But our test suite touches only a very
> tiny fraction of the tzdata files, so even if there's some
> corruption in them we wouldn't necessarily notice it.

Apologies, you are correct about "make check". I think it's still bothersome that a bug can hide in plain sight, but I've not thought about how to supplement tests to fix that.

Still waiting on LLVM/Clang to compile...

> regards, tom lane

best.

-greg

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