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Use bitwise rotate functions in more places

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There were a number of places in the code that used bespoke bit-twiddling
expressions to do bitwise rotation. While we've had pg_rotate_right32()
for a while now, we hadn't gotten around to standardizing on that. Do so
now. Since many potential call sites look more natural with the "left"
equivalent, add that function too.

Reviewed by Tom Lane and Yugo Nagata

Discussion:
https://www.postgresql.org/message-id/CAFBsxsH7c1LC0CGZ0ADCBXLHU5-%3DKNXx-r7tHYPAW51b2HK4Qw%40mail.gmail.com
This commit is contained in:
John Naylor
2022-02-20 13:22:08 +07:00
parent d7a978601d
commit 4b35408f1e
9 changed files with 28 additions and 25 deletions
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4
src/backend/executor/execGrouping.c
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@ -459,8 +459,8 @@ TupleHashTableHash_internal(struct tuplehash_hash *tb,
Datum attr;
bool isNull;
/* rotate hashkey left 1 bit at each step */
hashkey = (hashkey << 1) | ((hashkey & 0x80000000) ? 1 : 0);
/* combine successive hashkeys by rotating */
hashkey = pg_rotate_left32(hashkey, 1);
attr = slot_getattr(slot, att, &isNull);

4
src/backend/executor/nodeHash.c
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@ -1840,8 +1840,8 @@ ExecHashGetHashValue(HashJoinTable hashtable,
Datum keyval;
bool isNull;
/* rotate hashkey left 1 bit at each step */
hashkey = (hashkey << 1) | ((hashkey & 0x80000000) ? 1 : 0);
/* combine successive hashkeys by rotating */
hashkey = pg_rotate_left32(hashkey, 1);
/*
* Get the join attribute value of the tuple

8
src/backend/executor/nodeMemoize.c
View File

@ -166,8 +166,8 @@ MemoizeHash_hash(struct memoize_hash *tb, const MemoizeKey *key)
{
for (int i = 0; i < numkeys; i++)
{
/* rotate hashkey left 1 bit at each step */
hashkey = (hashkey << 1) | ((hashkey & 0x80000000) ? 1 : 0);
/* combine successive hashkeys by rotating */
hashkey = pg_rotate_left32(hashkey, 1);
if (!pslot->tts_isnull[i]) /* treat nulls as having hash key 0 */
{
@ -189,8 +189,8 @@ MemoizeHash_hash(struct memoize_hash *tb, const MemoizeKey *key)
for (int i = 0; i < numkeys; i++)
{
/* rotate hashkey left 1 bit at each step */
hashkey = (hashkey << 1) | ((hashkey & 0x80000000) ? 1 : 0);
/* combine successive hashkeys by rotating */
hashkey = pg_rotate_left32(hashkey, 1);
if (!pslot->tts_isnull[i]) /* treat nulls as having hash key 0 */
{