diff --git a/src/backend/parser/scan.l b/src/backend/parser/scan.l
index 9f9d8a17061..6e6824faebd 100644
--- a/src/backend/parser/scan.l
+++ b/src/backend/parser/scan.l
@@ -39,6 +39,7 @@
 #include "parser/gramparse.h"
 #include "parser/parser.h"		/* only needed for GUC variables */
 #include "parser/scansup.h"
+#include "port/pg_bitutils.h"
 #include "mb/pg_wchar.h"
 }
 
@@ -1253,10 +1254,7 @@ addlit(char *ytext, int yleng, core_yyscan_t yyscanner)
 	/* enlarge buffer if needed */
 	if ((yyextra->literallen + yleng) >= yyextra->literalalloc)
 	{
-		do
-		{
-			yyextra->literalalloc *= 2;
-		} while ((yyextra->literallen + yleng) >= yyextra->literalalloc);
+		yyextra->literalalloc = pg_nextpower2_32(yyextra->literallen + yleng + 1);
 		yyextra->literalbuf = (char *) repalloc(yyextra->literalbuf,
 												yyextra->literalalloc);
 	}
diff --git a/src/backend/storage/ipc/shm_mq.c b/src/backend/storage/ipc/shm_mq.c
index 8a46962f939..446f20df461 100644
--- a/src/backend/storage/ipc/shm_mq.c
+++ b/src/backend/storage/ipc/shm_mq.c
@@ -20,6 +20,7 @@
 
 #include "miscadmin.h"
 #include "pgstat.h"
+#include "port/pg_bitutils.h"
 #include "postmaster/bgworker.h"
 #include "storage/procsignal.h"
 #include "storage/shm_mq.h"
@@ -720,14 +721,17 @@ shm_mq_receive(shm_mq_handle *mqh, Size *nbytesp, void **datap, bool nowait)
 		 */
 		if (mqh->mqh_buflen < nbytes)
 		{
-			Size		newbuflen = Max(mqh->mqh_buflen, MQH_INITIAL_BUFSIZE);
+			Size		newbuflen;
 
 			/*
-			 * Double the buffer size until the payload fits, but limit to
-			 * MaxAllocSize.
+			 * Increase size to the next power of 2 that's >= nbytes, but
+			 * limit to MaxAllocSize.
 			 */
-			while (newbuflen < nbytes)
-				newbuflen *= 2;
+#if SIZEOF_SIZE_T == 4
+			newbuflen = pg_nextpower2_32(nbytes);
+#else
+			newbuflen = pg_nextpower2_64(nbytes);
+#endif
 			newbuflen = Min(newbuflen, MaxAllocSize);
 
 			if (mqh->mqh_buffer != NULL)
diff --git a/src/backend/storage/lmgr/lwlock.c b/src/backend/storage/lmgr/lwlock.c
index 55b9d7970ec..ffb6fa36cc5 100644
--- a/src/backend/storage/lmgr/lwlock.c
+++ b/src/backend/storage/lmgr/lwlock.c
@@ -79,6 +79,7 @@
 #include "miscadmin.h"
 #include "pg_trace.h"
 #include "pgstat.h"
+#include "port/pg_bitutils.h"
 #include "postmaster/postmaster.h"
 #include "replication/slot.h"
 #include "storage/ipc.h"
@@ -659,9 +660,7 @@ LWLockRegisterTranche(int tranche_id, const char *tranche_name)
 	{
 		int			newalloc;
 
-		newalloc = Max(LWLockTrancheNamesAllocated, 8);
-		while (newalloc <= tranche_id)
-			newalloc *= 2;
+		newalloc = pg_nextpower2_32(Max(8, tranche_id + 1));
 
 		if (LWLockTrancheNames == NULL)
 			LWLockTrancheNames = (const char **)
@@ -715,10 +714,7 @@ RequestNamedLWLockTranche(const char *tranche_name, int num_lwlocks)
 
 	if (NamedLWLockTrancheRequests >= NamedLWLockTrancheRequestsAllocated)
 	{
-		int			i = NamedLWLockTrancheRequestsAllocated;
-
-		while (i <= NamedLWLockTrancheRequests)
-			i *= 2;
+		int			i = pg_nextpower2_32(NamedLWLockTrancheRequests + 1);
 
 		NamedLWLockTrancheRequestArray = (NamedLWLockTrancheRequest *)
 			repalloc(NamedLWLockTrancheRequestArray,
diff --git a/src/backend/tsearch/spell.c b/src/backend/tsearch/spell.c
index ebc89604ac2..934be3d7d33 100644
--- a/src/backend/tsearch/spell.c
+++ b/src/backend/tsearch/spell.c
@@ -1600,7 +1600,8 @@ MergeAffix(IspellDict *Conf, int a1, int a2)
 	else if (*Conf->AffixData[a2] == '\0')
 		return a1;
 
-	while (Conf->nAffixData + 1 >= Conf->lenAffixData)
+	/* Double the size of AffixData if there's not enough space */
+	if (Conf->nAffixData + 1 >= Conf->lenAffixData)
 	{
 		Conf->lenAffixData *= 2;
 		Conf->AffixData = (char **) repalloc(Conf->AffixData,
diff --git a/src/backend/tsearch/ts_parse.c b/src/backend/tsearch/ts_parse.c
index 92d95b4bd49..d978c8850de 100644
--- a/src/backend/tsearch/ts_parse.c
+++ b/src/backend/tsearch/ts_parse.c
@@ -436,7 +436,7 @@ parsetext(Oid cfgId, ParsedText *prs, char *buf, int buflen)
 static void
 hladdword(HeadlineParsedText *prs, char *buf, int buflen, int type)
 {
-	while (prs->curwords >= prs->lenwords)
+	if (prs->curwords >= prs->lenwords)
 	{
 		prs->lenwords *= 2;
 		prs->words = (HeadlineWordEntry *) repalloc((void *) prs->words, prs->lenwords * sizeof(HeadlineWordEntry));
diff --git a/src/backend/utils/cache/inval.c b/src/backend/utils/cache/inval.c
index dcfd9e83893..d22cc5a93b3 100644
--- a/src/backend/utils/cache/inval.c
+++ b/src/backend/utils/cache/inval.c
@@ -106,6 +106,7 @@
 #include "catalog/catalog.h"
 #include "catalog/pg_constraint.h"
 #include "miscadmin.h"
+#include "port/pg_bitutils.h"
 #include "storage/sinval.h"
 #include "storage/smgr.h"
 #include "utils/catcache.h"
@@ -799,8 +800,7 @@ MakeSharedInvalidMessagesArray(const SharedInvalidationMessage *msgs, int n)
 
 	if ((numSharedInvalidMessagesArray + n) > maxSharedInvalidMessagesArray)
 	{
-		while ((numSharedInvalidMessagesArray + n) > maxSharedInvalidMessagesArray)
-			maxSharedInvalidMessagesArray *= 2;
+		maxSharedInvalidMessagesArray = pg_nextpower2_32(numSharedInvalidMessagesArray + n);
 
 		SharedInvalidMessagesArray = repalloc(SharedInvalidMessagesArray,
 											  maxSharedInvalidMessagesArray
diff --git a/src/backend/utils/cache/typcache.c b/src/backend/utils/cache/typcache.c
index de96e96c8fd..976bd9e61aa 100644
--- a/src/backend/utils/cache/typcache.c
+++ b/src/backend/utils/cache/typcache.c
@@ -60,6 +60,7 @@
 #include "executor/executor.h"
 #include "lib/dshash.h"
 #include "optimizer/optimizer.h"
+#include "port/pg_bitutils.h"
 #include "storage/lwlock.h"
 #include "utils/builtins.h"
 #include "utils/catcache.h"
@@ -1708,10 +1709,7 @@ ensure_record_cache_typmod_slot_exists(int32 typmod)
 
 	if (typmod >= RecordCacheArrayLen)
 	{
-		int32		newlen = RecordCacheArrayLen * 2;
-
-		while (typmod >= newlen)
-			newlen *= 2;
+		int32		newlen = pg_nextpower2_32(typmod + 1);
 
 		RecordCacheArray = (TupleDesc *) repalloc(RecordCacheArray,
 												  newlen * sizeof(TupleDesc));