On Thu, Dec 14, 2017 at 6:37 AM, Andres Freund <and...@anarazel.de> wrote: > https://buildfarm.postgresql.org/cgi-bin/show_log.pl?nm=dangomushi&dt=2017-12-13%2018%3A00%3A18 > > which seems half like a compiler bug to me. But either way, we gotta > work around it. I suspect the reason configure test doesn't > sufficiently detect this here is because it's testing the function with > constant arguments.
This uses clang 5.0 and I can reproduce the failure manually: $ clang --version clang version 5.0.0 (tags/RELEASE_500/final) Target: armv7l-unknown-linux-gnueabihf Thread model: posix InstalledDir: /usr/bin Note that on the same machine using gcc 7.2.0 I am seeing no compilation failures. ArchLinux maintainers can be sometimes wild in the versions they push, I have seen that in the past. And Arch ARM has less resources I think. Also, gull is complaining with the same failure: https://buildfarm.postgresql.org/cgi-bin/show_log.pl?nm=gull&dt=2017-12-13%2004%3A20%3A18 ARMv7 is used there as well, with clang 3.8, so this combination is deadly. > Could you perhaps test whether replacing PGAC_C_BUILTIN_OP_OVERFLOW's body > with something like > result > PG_INT64_TYPE a; > PG_INT64_TYPE b; > PG_INT64_TYPE result; > __builtin_mul_overflow(*(volatile PG_INT64_TYPE*) &a, *(volatile > PG_INT64_TYPE*) &b, &result); > > makes it fail? I'd rather not test this via the buildfarm, given that > dangomushi isn't the most frequently running / fastest animal. The tests are run once per day to not push too much its SD card. Let me see... If I enforce also a cast on "result" as well then I am able to compile correctly, which gives me the attached. make check also works, I haven't taken the time to do a complete test run though, this would take way longer on dangomushi. -- Michael
builtin-multi-conf.patch
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