diff --git a/src/backend/utils/adt/varlena.c b/src/backend/utils/adt/varlena.c
index 87ecf58ade..6d42bca1ea 100644
--- a/src/backend/utils/adt/varlena.c
+++ b/src/backend/utils/adt/varlena.c
@@ -3081,11 +3081,12 @@ byteaGetBit(PG_FUNCTION_ARGS)
 
 	len = VARSIZE_ANY_EXHDR(v);
 
-	if (n < 0 || n >= len * 8)
+	/* Do comparison arithmetic in int64 in case len exceeds INT_MAX/8 */
+	if (n < 0 || n >= (int64) len * 8)
 		ereport(ERROR,
 				(errcode(ERRCODE_ARRAY_SUBSCRIPT_ERROR),
 				 errmsg("index %d out of valid range, 0..%d",
-						n, len * 8 - 1)));
+						n, (int) Min((int64) len * 8 - 1, INT_MAX))));
 
 	byteNo = n / 8;
 	bitNo = n % 8;
@@ -3152,11 +3153,12 @@ byteaSetBit(PG_FUNCTION_ARGS)
 
 	len = VARSIZE(res) - VARHDRSZ;
 
-	if (n < 0 || n >= len * 8)
+	/* Do comparison arithmetic in int64 in case len exceeds INT_MAX/8 */
+	if (n < 0 || n >= (int64) len * 8)
 		ereport(ERROR,
 				(errcode(ERRCODE_ARRAY_SUBSCRIPT_ERROR),
 				 errmsg("index %d out of valid range, 0..%d",
-						n, len * 8 - 1)));
+						n, (int) Min((int64) len * 8 - 1, INT_MAX))));
 
 	byteNo = n / 8;
 	bitNo = n % 8;
diff --git a/src/test/regress/expected/strings.out b/src/test/regress/expected/strings.out
index 189bdffdca..ae7b1e15e8 100644
--- a/src/test/regress/expected/strings.out
+++ b/src/test/regress/expected/strings.out
@@ -1509,6 +1509,82 @@ SELECT sha512('The quick brown fox jumps over the lazy dog.');
  \x91ea1245f20d46ae9a037a989f54f1f790f0a47607eeb8a14d12890cea77a1bbc6c7ed9cf205e67b7f2b8fd4c7dfd3a7a8617e45f3c463d481c7e586c39ac1ed
 (1 row)
 
+--
+-- encode/decode
+--
+SELECT encode('\x1234567890abcdef00', 'hex');
+       encode       
+--------------------
+ 1234567890abcdef00
+(1 row)
+
+SELECT decode('1234567890abcdef00', 'hex');
+        decode        
+----------------------
+ \x1234567890abcdef00
+(1 row)
+
+SELECT encode(('\x' || repeat('1234567890abcdef0001', 7))::bytea, 'base64');
+                                    encode                                    
+------------------------------------------------------------------------------
+ EjRWeJCrze8AARI0VniQq83vAAESNFZ4kKvN7wABEjRWeJCrze8AARI0VniQq83vAAESNFZ4kKvN+
+ 7wABEjRWeJCrze8AAQ==
+(1 row)
+
+SELECT decode(encode(('\x' || repeat('1234567890abcdef0001', 7))::bytea,
+                     'base64'), 'base64');
+                                                                     decode                                                                     
+------------------------------------------------------------------------------------------------------------------------------------------------
+ \x1234567890abcdef00011234567890abcdef00011234567890abcdef00011234567890abcdef00011234567890abcdef00011234567890abcdef00011234567890abcdef0001
+(1 row)
+
+SELECT encode('\x1234567890abcdef00', 'escape');
+           encode            
+-----------------------------
+ \x124Vx\220\253\315\357\000
+(1 row)
+
+SELECT decode(encode('\x1234567890abcdef00', 'escape'), 'escape');
+        decode        
+----------------------
+ \x1234567890abcdef00
+(1 row)
+
+--
+-- get_bit/set_bit etc
+--
+SELECT get_bit('\x1234567890abcdef00'::bytea, 43);
+ get_bit 
+---------
+       1
+(1 row)
+
+SELECT get_bit('\x1234567890abcdef00'::bytea, 99);  -- error
+ERROR:  index 99 out of valid range, 0..71
+SELECT set_bit('\x1234567890abcdef00'::bytea, 43, 0);
+       set_bit        
+----------------------
+ \x1234567890a3cdef00
+(1 row)
+
+SELECT set_bit('\x1234567890abcdef00'::bytea, 99, 0);  -- error
+ERROR:  index 99 out of valid range, 0..71
+SELECT get_byte('\x1234567890abcdef00'::bytea, 3);
+ get_byte 
+----------
+      120
+(1 row)
+
+SELECT get_byte('\x1234567890abcdef00'::bytea, 99);  -- error
+ERROR:  index 99 out of valid range, 0..8
+SELECT set_byte('\x1234567890abcdef00'::bytea, 7, 11);
+       set_byte       
+----------------------
+ \x1234567890abcd0b00
+(1 row)
+
+SELECT set_byte('\x1234567890abcdef00'::bytea, 99, 11);  -- error
+ERROR:  index 99 out of valid range, 0..8
 --
 -- test behavior of escape_string_warning and standard_conforming_strings options
 --
diff --git a/src/test/regress/sql/strings.sql b/src/test/regress/sql/strings.sql
index f2203ef1b1..9433ec1550 100644
--- a/src/test/regress/sql/strings.sql
+++ b/src/test/regress/sql/strings.sql
@@ -526,6 +526,29 @@ SELECT sha384('The quick brown fox jumps over the lazy dog.');
 SELECT sha512('');
 SELECT sha512('The quick brown fox jumps over the lazy dog.');
 
+--
+-- encode/decode
+--
+SELECT encode('\x1234567890abcdef00', 'hex');
+SELECT decode('1234567890abcdef00', 'hex');
+SELECT encode(('\x' || repeat('1234567890abcdef0001', 7))::bytea, 'base64');
+SELECT decode(encode(('\x' || repeat('1234567890abcdef0001', 7))::bytea,
+                     'base64'), 'base64');
+SELECT encode('\x1234567890abcdef00', 'escape');
+SELECT decode(encode('\x1234567890abcdef00', 'escape'), 'escape');
+
+--
+-- get_bit/set_bit etc
+--
+SELECT get_bit('\x1234567890abcdef00'::bytea, 43);
+SELECT get_bit('\x1234567890abcdef00'::bytea, 99);  -- error
+SELECT set_bit('\x1234567890abcdef00'::bytea, 43, 0);
+SELECT set_bit('\x1234567890abcdef00'::bytea, 99, 0);  -- error
+SELECT get_byte('\x1234567890abcdef00'::bytea, 3);
+SELECT get_byte('\x1234567890abcdef00'::bytea, 99);  -- error
+SELECT set_byte('\x1234567890abcdef00'::bytea, 7, 11);
+SELECT set_byte('\x1234567890abcdef00'::bytea, 99, 11);  -- error
+
 --
 -- test behavior of escape_string_warning and standard_conforming_strings options
 --