From: PG Bug reporting form <noreply@postgresql.org>
To: pgsql-bugs@lists.postgresql.org
Cc: exclusion@gmail.com
Subject: BUG #18240: Undefined behaviour in cash_mul_flt8() and friends
Date: Mon, 11 Dec 2023 06:00:02 +0000
Message-ID: <18240-c5da758d7dc1ecf0@postgresql.org> (raw)
The following bug has been logged on the website:
Bug reference: 18240
Logged by: Alexander Lakhin
Email address: exclusion@gmail.com
PostgreSQL version: 16.1
Operating system: Ubuntu 22.04
Description:
The following multiplication:
SELECT 1_000_000_000::money * 1_000_000_000::float8;
gives the incorrect result:
-$92,233,720,368,547,758.08
UBSan detects undefined behaviour:
cash.c:669:11: runtime error: 1e+20 is outside the range of representable
values of type 'long'
#0 0x55d66011b73a in cash_mul_flt8
.../src/backend/utils/adt/cash.c:669:11
The same is observed with float4:
cash.c:719:11: runtime error: 1e+20 is outside the range of representable
values of type 'long'
#0 0x55f2adc46072 in cash_mul_flt4
.../src/backend/utils/adt/cash.c:719:11
And with float8 * money...
Reproduced on REL9_6_0 (but the defect is much older, AFAICS) .. HEAD.
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Subject: Re: BUG #18240: Undefined behaviour in cash_mul_flt8() and friends
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