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Fix some incorrect preprocessor tests in tuplesort specializations

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697492434 added 3 new quicksort specialization functions for common
datatypes.

That commit was not very consistent in how it would determine if we're
compiling for 32-bit or 64-bit machines.  It would sometimes use
USE_FLOAT8_BYVAL and at other times check if SIZEOF_DATUM == 8.  This
could cause theoretical problems due to the way USE_FLOAT8_BYVAL is now
defined based on SIZEOF_VOID_P >= 8.  If pointers for some reason were
ever larger than 8-bytes then we'd end up doing 32-bit comparisons
mistakenly.  Let's just always check SIZEOF_DATUM >= 8.

It also seems that ssup_datum_signed_cmp is just never used on 32-bit
builds, so let's just ifdef that out to make sure we never accidentally
use that comparison function on such machines.  This also allows us to
ifdef out 1 of the 3 new specialization quicksort functions in 32-bit
builds which seems to shrink down the binary by over 4KB on my machine.

In passing, also add the missing DatumGetInt32() / DatumGetInt64() macros
in the comparison functions.

Discussion: https://postgr.es/m/CAApHDvqcQExRhtRa9hJrJB_5egs3SUfOcutP3m+3HO8A+fZTPA@mail.gmail.com
Reviewed-by: John Naylor
This commit is contained in:
David Rowley
2022-05-11 11:38:13 +12:00
parent aff45c879e
commit c90c16591c
4 changed files with 18 additions and 13 deletions
src
backend
access
nbtree
nbtcompare.c
utils
adt
timestamp.c
sort
tuplesort.c
include
utils
sortsupport.h

4
src/backend/utils/adt/timestamp.c

@ -2176,7 +2176,7 @@ timestamp_cmp(PG_FUNCTION_ARGS)
PG_RETURN_INT32(timestamp_cmp_internal(dt1, dt2));
}
#ifndef USE_FLOAT8_BYVAL
#if SIZEOF_DATUM < 8
/* note: this is used for timestamptz also */
static int
timestamp_fastcmp(Datum x, Datum y, SortSupport ssup)
@ -2193,7 +2193,7 @@ timestamp_sortsupport(PG_FUNCTION_ARGS)
{
SortSupport ssup = (SortSupport) PG_GETARG_POINTER(0);
#ifdef USE_FLOAT8_BYVAL
#if SIZEOF_DATUM >= 8
/*
* If this build has pass-by-value timestamps, then we can use a standard
* comparator function.