address PR comment and update gate count

Author: nishatkoti

barretenberg/cpp/src/barretenberg/dsl/acir_format/blake2s_constraint.cpp

@@ -25,12 +25,10 @@ template <typename Builder> void create_blake2s_constraints(Builder& builder, co
         auto witness_index = witness_index_num_bits.blackbox_input;
         field_ct element = to_field_ct(witness_index, builder);
 
-        // num_bytes = ceil(witness_index_num_bits.num_bits/8). Here, num_bits is set to 8 when constructing the vector
-        // of inputs in the Blake2s constraint. Hence, we set num_bytes = 1.
-        uint32_t num_bytes = 1;
-
-        // byte_array_ct(field, num_bytes) constructor adds range constraints for each byte
-        byte_array_ct element_bytes(element, num_bytes);
+        // byte_array_ct(field, num_bytes) constructor adds range constraints for each byte. Note that num_bytes =
+        // ceil(witness_index_num_bits.num_bits/8). Here, num_bits is set to 8 when constructing the vector of inputs in
+        // the Blake2s constraint. Hence, we set num_bytes = 1.
+        byte_array_ct element_bytes(element, 1);
 
         // Safe write: both arr and element_bytes are constrained
         arr.write(element_bytes);

barretenberg/cpp/src/barretenberg/dsl/acir_format/blake3_constraint.cpp

@@ -23,12 +23,10 @@ template <typename Builder> void create_blake3_constraints(Builder& builder, con
         auto witness_index = witness_index_num_bits.blackbox_input;
         field_ct element = to_field_ct(witness_index, builder);
 
-        // num_bytes = ceil(witness_index_num_bits.num_bits/8). Here, num_bits is set to 8 when constructing the vector
-        // of inputs in the Blake3 constraint. Hence, we set num_bytes = 1.
-        uint32_t num_bytes = 1;
-
-        // byte_array_ct(field, num_bytes) constructor adds range constraints for each byte
-        byte_array_ct element_bytes(element, num_bytes);
+        // byte_array_ct(field, num_bytes) constructor adds range constraints for each byte. Note that num_bytes =
+        // ceil(witness_index_num_bits.num_bits/8). Here, num_bits is set to 8 when constructing the vector of inputs in
+        // the Blake3 constraint. Hence, we set num_bytes = 1.
+        byte_array_ct element_bytes(element, 1);
 
         // Safe write: both arr and element_bytes are constrained
         arr.write(element_bytes);

barretenberg/cpp/src/barretenberg/dsl/acir_format/gate_count_constants.hpp

@@ -38,8 +38,8 @@ template <typename Builder> inline constexpr size_t ECDSA_SECP256K1 = 41994 + ZE
 template <typename Builder>
 inline constexpr size_t ECDSA_SECP256R1 = 72209 + ZERO_GATE + (IsMegaBuilder<Builder> ? 2 : 0);
 
-template <typename Builder> inline constexpr size_t BLAKE2S = 2959 + ZERO_GATE + MEGA_OFFSET<Builder>;
-template <typename Builder> inline constexpr size_t BLAKE3 = 2165 + ZERO_GATE + MEGA_OFFSET<Builder>;
+template <typename Builder> inline constexpr size_t BLAKE2S = 2952 + ZERO_GATE + MEGA_OFFSET<Builder>;
+template <typename Builder> inline constexpr size_t BLAKE3 = 2158 + ZERO_GATE + MEGA_OFFSET<Builder>;
 template <typename Builder> inline constexpr size_t KECCAK_PERMUTATION = 17387 + ZERO_GATE + MEGA_OFFSET<Builder>;
 template <typename Builder> inline constexpr size_t POSEIDON2_PERMUTATION = 73 + ZERO_GATE + MEGA_OFFSET<Builder>;
 template <typename Builder> inline constexpr size_t MULTI_SCALAR_MUL = 3550 + ZERO_GATE;

barretenberg/cpp/src/barretenberg/dsl/acir_format/opcode_gate_count.test.cpp

@@ -436,7 +436,7 @@ TYPED_TEST(OpcodeGateCountTests, Blake2s)
 
     blake2s_constraint.inputs.push_back(Blake2sInput{
         .blackbox_input = WitnessOrConstant<bb::fr>::from_index(0),
-        .num_bits = 32,
+        .num_bits = 8,
     });
 
     for (size_t i = 0; i < 32; ++i) {
@@ -466,7 +466,7 @@ TYPED_TEST(OpcodeGateCountTests, Blake3)
 
     blake3_constraint.inputs.push_back(Blake3Input{
         .blackbox_input = WitnessOrConstant<bb::fr>::from_index(0),
-        .num_bits = 32,
+        .num_bits = 8,
     });
 
     for (size_t i = 0; i < 32; ++i) {