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Re: LLVM miscompiles numeric.c access to short numeric var headers - Mailing list pgsql-hackers

From Tom Lane
Subject Re: LLVM miscompiles numeric.c access to short numeric var headers
Date
Msg-id 2520.1447339140@sss.pgh.pa.us
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In response to LLVM miscompiles numeric.c access to short numeric var headers  (Greg Stark <stark@mit.edu>)
Responses Re: LLVM miscompiles numeric.c access to short numeric var headers
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Greg Stark <stark@mit.edu> writes:
> In numeric.c we have the short numeric headers that have one uint16
> (in addition to the varlena header) followed by digits. When compiling
> with -O2 on x86-64 LLVM now seems to use a 4-byte access.

Either that's a reportable compiler bug, or someplace nearby we've
casted the pointer to something that would require a 4-byte struct.
I'm not sure which code you're looking at exactly, but maybe we're
using "union NumericChoice" prematurely?
        regards, tom lane

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