Remove restrict from const objects (#6791)

We don't really need it if we systematically use restrict on the
read/write objects.

This is a minor refactoring to avoid confusion, shouldn't actually
change any behavior or code generation.

Author: akuzm

tsl/src/compression/array.c

@@ -494,7 +494,7 @@ text_array_decompress_all_serialized_no_header(StringInfo si, bool has_nulls,
 	Simple8bRleSerialized *sizes_serialized = bytes_deserialize_simple8b_and_advance(si);
 
 	uint32 n_notnull;
-	uint32 *restrict sizes = simple8brle_decompress_all_uint32(sizes_serialized, &n_notnull);
+	const uint32 *sizes = simple8brle_decompress_all_uint32(sizes_serialized, &n_notnull);
 	const uint32 n_total = has_nulls ? nulls_serialized->num_elements : n_notnull;
 	CheckCompressedData(n_total >= n_notnull);
 
@@ -507,7 +507,7 @@ text_array_decompress_all_serialized_no_header(StringInfo si, bool has_nulls,
 	uint32 offset = 0;
 	for (uint32 i = 0; i < n_notnull; i++)
 	{
-		void *unaligned = consumeCompressedData(si, sizes[i]);
+		const void *unaligned = consumeCompressedData(si, sizes[i]);
 
 		/*
 		 * We start reading from the end of previous datum, but this pointer
@@ -517,7 +517,8 @@ text_array_decompress_all_serialized_no_header(StringInfo si, bool has_nulls,
 		 *
 		 * See the corresponding row-by-row code in bytes_to_datum_and_advance().
 		 */
-		void *vardata = DatumGetPointer(att_align_pointer(unaligned, TYPALIGN_INT, -1, unaligned));
+		const void *vardata =
+			DatumGetPointer(att_align_pointer(unaligned, TYPALIGN_INT, -1, unaligned));
 
 		/*
 		 * Check for potentially corrupt varlena headers since we're reading them
@@ -578,7 +579,7 @@ text_array_decompress_all_serialized_no_header(StringInfo si, bool has_nulls,
 		 * We have decompressed the data with nulls skipped, reshuffle it
 		 * according to the nulls bitmap.
 		 */
-		Simple8bRleBitmap nulls = simple8brle_bitmap_decompress(nulls_serialized);
+		const Simple8bRleBitmap nulls = simple8brle_bitmap_decompress(nulls_serialized);
 		CheckCompressedData(n_notnull + simple8brle_bitmap_num_ones(&nulls) == n_total);
 
 		int current_notnull_element = n_notnull - 1;

tsl/src/compression/deltadelta_impl.c

@@ -31,8 +31,7 @@ FUNCTION_NAME(delta_delta_decompress_all, ELEMENT_TYPE)(Datum compressed, Memory
 	 * test_delta4().
 	 */
 	uint32 num_deltas;
-	const uint64 *restrict deltas_zigzag =
-		simple8brle_decompress_all_uint64(deltas_compressed, &num_deltas);
+	const uint64 *deltas_zigzag = simple8brle_decompress_all_uint64(deltas_compressed, &num_deltas);
 
 	Simple8bRleBitmap nulls = { 0 };
 	if (has_nulls)

tsl/src/compression/gorilla.c

@@ -867,7 +867,7 @@ unpack_leading_zeros_array(BitArray *bitarray, uint32 *_n)
 	for (uint32 lane = 0; lane < n_lanes; lane++)
 	{
 		uint8 *restrict lane_dest = &dest[lane * LANE_OUTPUTS];
-		const uint8 *restrict lane_src = &((uint8 *) bitarray->buckets.data)[lane * LANE_INPUTS];
+		const uint8 *lane_src = &((uint8 *) bitarray->buckets.data)[lane * LANE_INPUTS];
 		for (uint32 output_in_lane = 0; output_in_lane < LANE_OUTPUTS; output_in_lane++)
 		{
 			const int startbit_abs = output_in_lane * BITS_PER_LEADING_ZEROS;

tsl/src/compression/gorilla_impl.c

@@ -40,19 +40,19 @@ FUNCTION_NAME(gorilla_decompress_all, ELEMENT_TYPE)(CompressedGorillaData *goril
 	CheckCompressedData(n_total >= n_notnull);
 
 	/* Unpack the basic compressed data parts. */
-	Simple8bRleBitmap tag0s = simple8brle_bitmap_prefixsums(gorilla_data->tag0s);
-	Simple8bRleBitmap tag1s = simple8brle_bitmap_prefixsums(gorilla_data->tag1s);
+	const Simple8bRleBitmap tag0s = simple8brle_bitmap_prefixsums(gorilla_data->tag0s);
+	const Simple8bRleBitmap tag1s = simple8brle_bitmap_prefixsums(gorilla_data->tag1s);
 
 	BitArray leading_zeros_bitarray = gorilla_data->leading_zeros;
 	BitArrayIterator leading_zeros_iterator;
 	bit_array_iterator_init(&leading_zeros_iterator, &leading_zeros_bitarray);
 
 	uint32 num_leading_zeros_padded;
-	uint8 *restrict all_leading_zeros =
+	const uint8 *all_leading_zeros =
 		unpack_leading_zeros_array(&gorilla_data->leading_zeros, &num_leading_zeros_padded);
 
 	uint32 num_bit_widths;
-	uint8 *restrict bit_widths =
+	const uint8 *bit_widths =
 		simple8brle_decompress_all_uint8(gorilla_data->num_bits_used_per_xor, &num_bit_widths);
 
 	BitArray xors_bitarray = gorilla_data->xors;
@@ -147,7 +147,7 @@ FUNCTION_NAME(gorilla_decompress_all, ELEMENT_TYPE)(CompressedGorillaData *goril
 		 * We have decompressed the data with nulls skipped, reshuffle it
 		 * according to the nulls bitmap.
 		 */
-		Simple8bRleBitmap nulls = simple8brle_bitmap_decompress(gorilla_data->nulls);
+		const Simple8bRleBitmap nulls = simple8brle_bitmap_decompress(gorilla_data->nulls);
 		CheckCompressedData(n_notnull + simple8brle_bitmap_num_ones(&nulls) == n_total);
 
 		int current_notnull_element = n_notnull - 1;

tsl/src/compression/simple8b_rle_bitmap.h

@@ -15,30 +15,30 @@
 typedef struct Simple8bRleBitmap
 {
 	/* Either the bools or prefix sums, depending on the decompression method. */
-	void *data;
+	const void *data;
 
 	uint16 num_elements;
 	uint16 num_ones;
 } Simple8bRleBitmap;
 
 pg_attribute_always_inline static bool
-simple8brle_bitmap_get_at(Simple8bRleBitmap *bitmap, uint16 i)
+simple8brle_bitmap_get_at(const Simple8bRleBitmap *bitmap, uint16 i)
 {
 	/* We have some padding on the right but we shouldn't overrun it. */
 	Assert(i < ((bitmap->num_elements + 63) / 64 + 1) * 64);
 
-	return ((bool *restrict) bitmap->data)[i];
+	return ((const bool *) bitmap->data)[i];
 }
 
 pg_attribute_always_inline static uint16
-simple8brle_bitmap_prefix_sum(Simple8bRleBitmap *bitmap, uint16 i)
+simple8brle_bitmap_prefix_sum(const Simple8bRleBitmap *bitmap, uint16 i)
 {
 	Assert(i < ((bitmap->num_elements + 63) / 64 + 1) * 64);
-	return ((uint16 *restrict) bitmap->data)[i];
+	return ((const uint16 *) bitmap->data)[i];
 }
 
 pg_attribute_always_inline static uint16
-simple8brle_bitmap_num_ones(Simple8bRleBitmap *bitmap)
+simple8brle_bitmap_num_ones(const Simple8bRleBitmap *bitmap)
 {
 	return bitmap->num_ones;
 }

tsl/src/compression/simple8b_rle_decompress_all.h

@@ -36,7 +36,7 @@ FUNCTION_NAME(simple8brle_decompress_all_buf,
 	 */
 	Assert(num_blocks <= GLOBAL_MAX_ROWS_PER_COMPRESSION);
 	uint8 selector_values[GLOBAL_MAX_ROWS_PER_COMPRESSION];
-	const uint64 *restrict slots = compressed->slots;
+	const uint64 *slots = compressed->slots;
 	for (uint32 block_index = 0; block_index < num_blocks; block_index++)
 	{
 		const uint32 selector_slot = block_index / SIMPLE8B_SELECTORS_PER_SELECTOR_SLOT;
@@ -52,7 +52,7 @@ FUNCTION_NAME(simple8brle_decompress_all_buf,
 	 * Now decompress the individual blocks.
 	 */
 	uint32 decompressed_index = 0;
-	const uint64 *restrict blocks = compressed->slots + num_selector_slots;
+	const uint64 *blocks = compressed->slots + num_selector_slots;
 	for (uint32 block_index = 0; block_index < num_blocks; block_index++)
 	{
 		const uint8 selector_value = selector_values[block_index];

tsl/src/nodes/decompress_chunk/compressed_batch.c

@@ -539,7 +539,7 @@ compute_plain_qual(DecompressContext *dcontext, DecompressBatchState *batch_stat
 		const size_t n_vector_result_words = (vector->length + 63) / 64;
 		Assert((predicate_result != default_value_predicate_result) ||
 			   n_vector_result_words == 1); /* to placate Coverity. */
-		const uint64 *restrict validity = (uint64 *restrict) vector->buffers[0];
+		const uint64 *validity = (const uint64 *) vector->buffers[0];
 		for (size_t i = 0; i < n_vector_result_words; i++)
 		{
 			predicate_result[i] &= validity[i];

tsl/src/nodes/decompress_chunk/pred_vector_const_arithmetic_single.c

@@ -29,7 +29,7 @@ FUNCTION_NAME(PREDICATE_NAME, VECTOR_CTYPE,
 
 	/* Now run the predicate itself. */
 	const CONST_CTYPE constvalue = CONST_CONVERSION(constdatum);
-	const VECTOR_CTYPE *restrict vector = (VECTOR_CTYPE *restrict) arrow->buffers[1];
+	const VECTOR_CTYPE *vector = (const VECTOR_CTYPE *) arrow->buffers[1];
 
 	for (size_t outer = 0; outer < n / 64; outer++)
 	{

tsl/src/nodes/decompress_chunk/vector_predicates.c

@@ -71,7 +71,7 @@ vector_nulltest(const ArrowArray *arrow, int test_type, uint64 *restrict result)
 	const bool should_be_null = test_type == IS_NULL;
 
 	const uint16 bitmap_words = (arrow->length + 63) / 64;
-	const uint64 *restrict validity = (const uint64 *) arrow->buffers[0];
+	const uint64 *validity = (const uint64 *) arrow->buffers[0];
 	for (uint16 i = 0; i < bitmap_words; i++)
 	{
 		if (should_be_null)