perf(MerkleRoot): Simplify power-of-2 check

jan-ferdinand · jan-ferdinand · commit 5c3388a823a3 · 2025-01-30T14:23:21.000+01:00
diff --git a/tasm-lib/benchmarks/tasmlib_hashing_merkle_root.json b/tasm-lib/benchmarks/tasmlib_hashing_merkle_root.json
@@ -2,21 +2,21 @@
   {
     "name": "tasmlib_hashing_merkle_root",
     "benchmark_result": {
-      "clock_cycle_count": 4887,
-      "hash_table_height": 3162,
-      "u32_table_height": 48,
-      "op_stack_table_height": 10472,
+      "clock_cycle_count": 4879,
+      "hash_table_height": 3156,
+      "u32_table_height": 43,
+      "op_stack_table_height": 10464,
       "ram_table_height": 7673
     },
     "case": "CommonCase"
   },
   {
     "name": "tasmlib_hashing_merkle_root",
     "benchmark_result": {
-      "clock_cycle_count": 9520,
-      "hash_table_height": 6234,
-      "u32_table_height": 49,
-      "op_stack_table_height": 20734,
+      "clock_cycle_count": 9512,
+      "hash_table_height": 6228,
+      "u32_table_height": 44,
+      "op_stack_table_height": 20726,
       "ram_table_height": 15353
     },
     "case": "WorstCase"
diff --git a/tasm-lib/benchmarks/tasmlib_hashing_merkle_root_from_xfes.json b/tasm-lib/benchmarks/tasmlib_hashing_merkle_root_from_xfes.json
@@ -2,21 +2,21 @@
   {
     "name": "tasmlib_hashing_merkle_root_from_xfes",
     "benchmark_result": {
-      "clock_cycle_count": 7236,
-      "hash_table_height": 3234,
-      "u32_table_height": 104,
-      "op_stack_table_height": 12046,
+      "clock_cycle_count": 7228,
+      "hash_table_height": 3228,
+      "u32_table_height": 99,
+      "op_stack_table_height": 12038,
       "ram_table_height": 6653
     },
     "case": "CommonCase"
   },
   {
     "name": "tasmlib_hashing_merkle_root_from_xfes",
     "benchmark_result": {
-      "clock_cycle_count": 14173,
-      "hash_table_height": 6306,
-      "u32_table_height": 107,
-      "op_stack_table_height": 23844,
+      "clock_cycle_count": 14165,
+      "hash_table_height": 6300,
+      "u32_table_height": 102,
+      "op_stack_table_height": 23836,
       "ram_table_height": 13309
     },
     "case": "WorstCase"
diff --git a/tasm-lib/benchmarks/tasmlib_verifier_fri_verify.json b/tasm-lib/benchmarks/tasmlib_verifier_fri_verify.json
@@ -2,21 +2,21 @@
   {
     "name": "tasmlib_verifier_fri_verify",
     "benchmark_result": {
-      "clock_cycle_count": 43515,
-      "hash_table_height": 14670,
-      "u32_table_height": 18371,
-      "op_stack_table_height": 40829,
+      "clock_cycle_count": 43507,
+      "hash_table_height": 14658,
+      "u32_table_height": 18381,
+      "op_stack_table_height": 40821,
       "ram_table_height": 17564
     },
     "case": "CommonCase"
   },
   {
     "name": "tasmlib_verifier_fri_verify",
     "benchmark_result": {
-      "clock_cycle_count": 43515,
-      "hash_table_height": 14670,
-      "u32_table_height": 17762,
-      "op_stack_table_height": 40829,
+      "clock_cycle_count": 43507,
+      "hash_table_height": 14658,
+      "u32_table_height": 17772,
+      "op_stack_table_height": 40821,
       "ram_table_height": 17564
     },
     "case": "WorstCase"
diff --git a/tasm-lib/benchmarks/tasmlib_verifier_stark_verify_dynamic_inner_padded_height_256_fri_exp_4.json b/tasm-lib/benchmarks/tasmlib_verifier_stark_verify_dynamic_inner_padded_height_256_fri_exp_4.json
@@ -2,10 +2,10 @@
   {
     "name": "tasmlib_verifier_stark_verify_dynamic_inner_padded_height_256_fri_exp_4",
     "benchmark_result": {
-      "clock_cycle_count": 187678,
-      "hash_table_height": 138835,
-      "u32_table_height": 25449,
-      "op_stack_table_height": 165836,
+      "clock_cycle_count": 187670,
+      "hash_table_height": 138829,
+      "u32_table_height": 25459,
+      "op_stack_table_height": 165828,
       "ram_table_height": 289170
     },
     "case": "CommonCase"
diff --git a/tasm-lib/benchmarks/tasmlib_verifier_stark_verify_dynamic_inner_padded_height_512_fri_exp_4.json b/tasm-lib/benchmarks/tasmlib_verifier_stark_verify_dynamic_inner_padded_height_512_fri_exp_4.json
@@ -2,10 +2,10 @@
   {
     "name": "tasmlib_verifier_stark_verify_dynamic_inner_padded_height_512_fri_exp_4",
     "benchmark_result": {
-      "clock_cycle_count": 195182,
-      "hash_table_height": 146527,
+      "clock_cycle_count": 195174,
+      "hash_table_height": 146521,
       "u32_table_height": 34071,
-      "op_stack_table_height": 170540,
+      "op_stack_table_height": 170532,
       "ram_table_height": 290321
     },
     "case": "CommonCase"
diff --git a/tasm-lib/benchmarks/tasmlib_verifier_stark_verify_static_inner_padded_height_256_fri_exp_4.json b/tasm-lib/benchmarks/tasmlib_verifier_stark_verify_static_inner_padded_height_256_fri_exp_4.json
@@ -2,10 +2,10 @@
   {
     "name": "tasmlib_verifier_stark_verify_static_inner_padded_height_256_fri_exp_4",
     "benchmark_result": {
-      "clock_cycle_count": 175975,
-      "hash_table_height": 124789,
-      "u32_table_height": 25449,
-      "op_stack_table_height": 158030,
+      "clock_cycle_count": 175967,
+      "hash_table_height": 124783,
+      "u32_table_height": 25459,
+      "op_stack_table_height": 158022,
       "ram_table_height": 285271
     },
     "case": "CommonCase"
diff --git a/tasm-lib/benchmarks/tasmlib_verifier_stark_verify_static_inner_padded_height_512_fri_exp_4.json b/tasm-lib/benchmarks/tasmlib_verifier_stark_verify_static_inner_padded_height_512_fri_exp_4.json
@@ -2,10 +2,10 @@
   {
     "name": "tasmlib_verifier_stark_verify_static_inner_padded_height_512_fri_exp_4",
     "benchmark_result": {
-      "clock_cycle_count": 183479,
-      "hash_table_height": 132481,
+      "clock_cycle_count": 183471,
+      "hash_table_height": 132475,
       "u32_table_height": 34071,
-      "op_stack_table_height": 162734,
+      "op_stack_table_height": 162726,
       "ram_table_height": 286422
     },
     "case": "CommonCase"
diff --git a/tasm-lib/src/hashing/merkle_root.rs b/tasm-lib/src/hashing/merkle_root.rs
@@ -34,7 +34,6 @@ use crate::twenty_first::prelude::Inverse;
 pub struct MerkleRoot;
 
 impl MerkleRoot {
-    pub const ZERO_LEAFS_ERROR_ID: i128 = 430;
     pub const NUM_LEAFS_NOT_POWER_OF_2_ERROR_ID: i128 = 431;
 }
 
@@ -69,23 +68,13 @@ impl BasicSnippet for MerkleRoot {
                 addi 1
                 // _ leafs_len *leafs
 
-                /* assert the number of leafs is reasonable: some power of 2, not 0 */
+                /* assert the number of leafs is some power of 2 */
                 dup 1
-                push 0
-                eq
-                push 0
-                eq
-                assert error_id {Self::ZERO_LEAFS_ERROR_ID}
-
-                dup 1           // _ leafs_len *leafs leafs_len
-                log_2_floor
-                push 2
-                pow             // _ leafs_len *leafs (2^⌊log₂(leafs_len)⌋)
-                dup 2
+                pop_count
+                push 1
                 eq
                 assert error_id {Self::NUM_LEAFS_NOT_POWER_OF_2_ERROR_ID}
 
-
                 call {dyn_malloc}
                 // _ leafs_len *leafs *parent_level
 
@@ -210,7 +199,7 @@ impl BasicSnippet for MerkleRoot {
 
     fn sign_offs(&self) -> HashMap<Reviewer, SignOffFingerprint> {
         let mut sign_offs = HashMap::new();
-        sign_offs.insert(Reviewer("ferdinand"), 0x2f0791d17407d7dc.into());
+        sign_offs.insert(Reviewer("ferdinand"), 0x1c30ac983fdca9da.into());
         sign_offs
     }
 }
@@ -296,13 +285,13 @@ mod tests {
         test_assertion_failure(
             &ShadowedFunction::new(MerkleRoot),
             MerkleRoot.init_state(vec![], bfe!(0)).into(),
-            &[MerkleRoot::ZERO_LEAFS_ERROR_ID],
+            &[MerkleRoot::NUM_LEAFS_NOT_POWER_OF_2_ERROR_ID],
         );
     }
 
     #[proptest(cases = 100)]
     fn computing_root_of_tree_of_height_not_power_of_2_crashes_vm(
-        #[strategy(vec(arb(), 1..2048))]
+        #[strategy(vec(arb(), 0..2048))]
         #[filter(!#leafs.len().is_power_of_two())]
         leafs: Vec<Digest>,
         #[strategy(arb())] address: BFieldElement,
