Replace gratuitous memmove() with memcpy()

The index access methods all had similar code that copied the
passed-in scan keys to local storage.  They all used memmove() for
that, which is not wrong, but it seems confusing not to use memcpy()
when that would work.  Presumably, this was all once copied from
ancient code and never adjusted.

Discussion: https://www.postgresql.org/message-id/flat/f8c739d9-f48d-4187-b214-df3391ba41ab@eisentraut.org

contrib/bloom/blscan.c

@@ -55,10 +55,7 @@ blrescan(IndexScanDesc scan, ScanKey scankey, int nscankeys,
 	so->sign = NULL;
 
 	if (scankey && scan->numberOfKeys > 0)
-	{
-		memmove(scan->keyData, scankey,
-				scan->numberOfKeys * sizeof(ScanKeyData));
-	}
+		memcpy(scan->keyData, scankey, scan->numberOfKeys * sizeof(ScanKeyData));
 }
 
 /*

src/backend/access/brin/brin.c

@@ -956,8 +956,7 @@ brinrescan(IndexScanDesc scan, ScanKey scankey, int nscankeys,
 	 */
 
 	if (scankey && scan->numberOfKeys > 0)
-		memmove(scan->keyData, scankey,
-				scan->numberOfKeys * sizeof(ScanKeyData));
+		memcpy(scan->keyData, scankey, scan->numberOfKeys * sizeof(ScanKeyData));
 }
 
 /*

src/backend/access/gin/ginscan.c

@@ -447,10 +447,7 @@ ginrescan(IndexScanDesc scan, ScanKey scankey, int nscankeys,
 	ginFreeScanKeys(so);
 
 	if (scankey && scan->numberOfKeys > 0)
-	{
-		memmove(scan->keyData, scankey,
-				scan->numberOfKeys * sizeof(ScanKeyData));
-	}
+		memcpy(scan->keyData, scankey, scan->numberOfKeys * sizeof(ScanKeyData));
 }
 
 

src/backend/access/gist/gistscan.c

@@ -233,8 +233,7 @@ gistrescan(IndexScanDesc scan, ScanKey key, int nkeys,
 				fn_extras[i] = scan->keyData[i].sk_func.fn_extra;
 		}
 
-		memmove(scan->keyData, key,
-				scan->numberOfKeys * sizeof(ScanKeyData));
+		memcpy(scan->keyData, key, scan->numberOfKeys * sizeof(ScanKeyData));
 
 		/*
 		 * Modify the scan key so that the Consistent method is called for all
@@ -289,8 +288,7 @@ gistrescan(IndexScanDesc scan, ScanKey key, int nkeys,
 				fn_extras[i] = scan->orderByData[i].sk_func.fn_extra;
 		}
 
-		memmove(scan->orderByData, orderbys,
-				scan->numberOfOrderBys * sizeof(ScanKeyData));
+		memcpy(scan->orderByData, orderbys, scan->numberOfOrderBys * sizeof(ScanKeyData));
 
 		so->orderByTypes = (Oid *) palloc(scan->numberOfOrderBys * sizeof(Oid));
 

src/backend/access/hash/hash.c

@@ -415,11 +415,7 @@ hashrescan(IndexScanDesc scan, ScanKey scankey, int nscankeys,
 
 	/* Update scan key, if a new one is given */
 	if (scankey && scan->numberOfKeys > 0)
-	{
-		memmove(scan->keyData,
-				scankey,
-				scan->numberOfKeys * sizeof(ScanKeyData));
-	}
+		memcpy(scan->keyData, scankey, scan->numberOfKeys * sizeof(ScanKeyData));
 
 	so->hashso_buc_populated = false;
 	so->hashso_buc_split = false;

src/backend/access/nbtree/nbtree.c

@@ -404,9 +404,7 @@ btrescan(IndexScanDesc scan, ScanKey scankey, int nscankeys,
 	 * Reset the scan keys
 	 */
 	if (scankey && scan->numberOfKeys > 0)
-		memmove(scan->keyData,
-				scankey,
-				scan->numberOfKeys * sizeof(ScanKeyData));
+		memcpy(scan->keyData, scankey, scan->numberOfKeys * sizeof(ScanKeyData));
 	so->numberOfKeys = 0;		/* until _bt_preprocess_keys sets it */
 	so->numArrayKeys = 0;		/* ditto */
 }

src/backend/access/spgist/spgscan.c

@@ -384,16 +384,14 @@ spgrescan(IndexScanDesc scan, ScanKey scankey, int nscankeys,
 
 	/* copy scankeys into local storage */
 	if (scankey && scan->numberOfKeys > 0)
-		memmove(scan->keyData, scankey,
-				scan->numberOfKeys * sizeof(ScanKeyData));
+		memcpy(scan->keyData, scankey, scan->numberOfKeys * sizeof(ScanKeyData));
 
 	/* initialize order-by data if needed */
 	if (orderbys && scan->numberOfOrderBys > 0)
 	{
 		int			i;
 
-		memmove(scan->orderByData, orderbys,
-				scan->numberOfOrderBys * sizeof(ScanKeyData));
+		memcpy(scan->orderByData, orderbys, scan->numberOfOrderBys * sizeof(ScanKeyData));
 
 		for (i = 0; i < scan->numberOfOrderBys; i++)
 		{