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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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14
src/backend/utils/cache/catcache.c vendored
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@ -26,6 +26,7 @@
#include "catalog/pg_type.h"
#include "common/hashfn.h"
#include "miscadmin.h"
#include "port/pg_bitutils.h"
#ifdef CATCACHE_STATS
#include "storage/ipc.h" /* for on_proc_exit */
#endif
@ -281,25 +282,18 @@ CatalogCacheComputeHashValue(CatCache *cache, int nkeys,
{
case 4:
oneHash = (cc_hashfunc[3]) (v4);
hashValue ^= oneHash << 24;
hashValue ^= oneHash >> 8;
hashValue ^= pg_rotate_left32(oneHash, 24);
/* FALLTHROUGH */
case 3:
oneHash = (cc_hashfunc[2]) (v3);
hashValue ^= oneHash << 16;
hashValue ^= oneHash >> 16;
hashValue ^= pg_rotate_left32(oneHash, 16);
/* FALLTHROUGH */
case 2:
oneHash = (cc_hashfunc[1]) (v2);
hashValue ^= oneHash << 8;
hashValue ^= oneHash >> 24;
hashValue ^= pg_rotate_left32(oneHash, 8);
/* FALLTHROUGH */
case 1:
oneHash = (cc_hashfunc[0]) (v1);
hashValue ^= oneHash;
break;
default: