diff --git a/cranelift/zkasm_data/spectest/i32/generated/clz_1.zkasm b/cranelift/zkasm_data/spectest/i32/generated/clz_1.zkasm
new file mode 100644
index 000000000000..e9f95fbdec03
--- /dev/null
+++ b/cranelift/zkasm_data/spectest/i32/generated/clz_1.zkasm
@@ -0,0 +1,27 @@
+start:
+  0xffff => SP
+  zkPC + 2 => RR
+  :JMP(function_1)
+  :JMP(finalizeExecution)
+function_1:
+  SP - 1 => SP
+  RR :MSTORE(SP)
+  C :MSTORE(SP - 1)
+  E :MSTORE(SP - 2)
+  B :MSTORE(SP - 3)
+  SP - 4 => SP
+  4294967295n => B  ;; LoadConst32
+  FIXME: Inst::Cltz(Writable { reg: v199 }, Writable { reg: v197 }, Writable { reg: v198 }, v192, true, types::I32)
+  0n => B  ;; LoadConst32
+  B :ASSERT
+  SP + 4 => SP
+  $ => C :MLOAD(SP - 1)
+  $ => E :MLOAD(SP - 2)
+  $ => B :MLOAD(SP - 3)
+  $ => RR :MLOAD(SP)
+  SP + 1 => SP
+  :JMP(RR)
+finalizeExecution:
+  ${beforeLast()}  :JMPN(finalizeExecution)
+                   :JMP(start)
+INCLUDE "helpers/2-exp.zkasm"
\ No newline at end of file
diff --git a/cranelift/zkasm_data/spectest/i32/generated/clz_2.zkasm b/cranelift/zkasm_data/spectest/i32/generated/clz_2.zkasm
new file mode 100644
index 000000000000..547476f1946f
--- /dev/null
+++ b/cranelift/zkasm_data/spectest/i32/generated/clz_2.zkasm
@@ -0,0 +1,27 @@
+start:
+  0xffff => SP
+  zkPC + 2 => RR
+  :JMP(function_1)
+  :JMP(finalizeExecution)
+function_1:
+  SP - 1 => SP
+  RR :MSTORE(SP)
+  C :MSTORE(SP - 1)
+  E :MSTORE(SP - 2)
+  B :MSTORE(SP - 3)
+  SP - 4 => SP
+  0n => B  ;; LoadConst32
+  FIXME: Inst::Cltz(Writable { reg: v199 }, Writable { reg: v197 }, Writable { reg: v198 }, v192, true, types::I32)
+  32n => B  ;; LoadConst32
+  B :ASSERT
+  SP + 4 => SP
+  $ => C :MLOAD(SP - 1)
+  $ => E :MLOAD(SP - 2)
+  $ => B :MLOAD(SP - 3)
+  $ => RR :MLOAD(SP)
+  SP + 1 => SP
+  :JMP(RR)
+finalizeExecution:
+  ${beforeLast()}  :JMPN(finalizeExecution)
+                   :JMP(start)
+INCLUDE "helpers/2-exp.zkasm"
\ No newline at end of file
diff --git a/cranelift/zkasm_data/spectest/i32/generated/clz_3.zkasm b/cranelift/zkasm_data/spectest/i32/generated/clz_3.zkasm
new file mode 100644
index 000000000000..15439f0cbccf
--- /dev/null
+++ b/cranelift/zkasm_data/spectest/i32/generated/clz_3.zkasm
@@ -0,0 +1,27 @@
+start:
+  0xffff => SP
+  zkPC + 2 => RR
+  :JMP(function_1)
+  :JMP(finalizeExecution)
+function_1:
+  SP - 1 => SP
+  RR :MSTORE(SP)
+  C :MSTORE(SP - 1)
+  E :MSTORE(SP - 2)
+  B :MSTORE(SP - 3)
+  SP - 4 => SP
+  32768n => B  ;; LoadConst32
+  FIXME: Inst::Cltz(Writable { reg: v199 }, Writable { reg: v197 }, Writable { reg: v198 }, v192, true, types::I32)
+  16n => B  ;; LoadConst32
+  B :ASSERT
+  SP + 4 => SP
+  $ => C :MLOAD(SP - 1)
+  $ => E :MLOAD(SP - 2)
+  $ => B :MLOAD(SP - 3)
+  $ => RR :MLOAD(SP)
+  SP + 1 => SP
+  :JMP(RR)
+finalizeExecution:
+  ${beforeLast()}  :JMPN(finalizeExecution)
+                   :JMP(start)
+INCLUDE "helpers/2-exp.zkasm"
\ No newline at end of file
diff --git a/cranelift/zkasm_data/spectest/i32/generated/clz_4.zkasm b/cranelift/zkasm_data/spectest/i32/generated/clz_4.zkasm
new file mode 100644
index 000000000000..435e84c3c279
--- /dev/null
+++ b/cranelift/zkasm_data/spectest/i32/generated/clz_4.zkasm
@@ -0,0 +1,27 @@
+start:
+  0xffff => SP
+  zkPC + 2 => RR
+  :JMP(function_1)
+  :JMP(finalizeExecution)
+function_1:
+  SP - 1 => SP
+  RR :MSTORE(SP)
+  C :MSTORE(SP - 1)
+  E :MSTORE(SP - 2)
+  B :MSTORE(SP - 3)
+  SP - 4 => SP
+  255n => B  ;; LoadConst32
+  FIXME: Inst::Cltz(Writable { reg: v199 }, Writable { reg: v197 }, Writable { reg: v198 }, v192, true, types::I32)
+  24n => B  ;; LoadConst32
+  B :ASSERT
+  SP + 4 => SP
+  $ => C :MLOAD(SP - 1)
+  $ => E :MLOAD(SP - 2)
+  $ => B :MLOAD(SP - 3)
+  $ => RR :MLOAD(SP)
+  SP + 1 => SP
+  :JMP(RR)
+finalizeExecution:
+  ${beforeLast()}  :JMPN(finalizeExecution)
+                   :JMP(start)
+INCLUDE "helpers/2-exp.zkasm"
\ No newline at end of file
diff --git a/cranelift/zkasm_data/spectest/i32/generated/clz_5.zkasm b/cranelift/zkasm_data/spectest/i32/generated/clz_5.zkasm
new file mode 100644
index 000000000000..5f6bafb090c8
--- /dev/null
+++ b/cranelift/zkasm_data/spectest/i32/generated/clz_5.zkasm
@@ -0,0 +1,27 @@
+start:
+  0xffff => SP
+  zkPC + 2 => RR
+  :JMP(function_1)
+  :JMP(finalizeExecution)
+function_1:
+  SP - 1 => SP
+  RR :MSTORE(SP)
+  C :MSTORE(SP - 1)
+  E :MSTORE(SP - 2)
+  B :MSTORE(SP - 3)
+  SP - 4 => SP
+  2147483648n => B  ;; LoadConst32
+  FIXME: Inst::Cltz(Writable { reg: v199 }, Writable { reg: v197 }, Writable { reg: v198 }, v192, true, types::I32)
+  0n => B  ;; LoadConst32
+  B :ASSERT
+  SP + 4 => SP
+  $ => C :MLOAD(SP - 1)
+  $ => E :MLOAD(SP - 2)
+  $ => B :MLOAD(SP - 3)
+  $ => RR :MLOAD(SP)
+  SP + 1 => SP
+  :JMP(RR)
+finalizeExecution:
+  ${beforeLast()}  :JMPN(finalizeExecution)
+                   :JMP(start)
+INCLUDE "helpers/2-exp.zkasm"
\ No newline at end of file
diff --git a/cranelift/zkasm_data/spectest/i32/generated/clz_6.zkasm b/cranelift/zkasm_data/spectest/i32/generated/clz_6.zkasm
new file mode 100644
index 000000000000..f4eeca15b047
--- /dev/null
+++ b/cranelift/zkasm_data/spectest/i32/generated/clz_6.zkasm
@@ -0,0 +1,27 @@
+start:
+  0xffff => SP
+  zkPC + 2 => RR
+  :JMP(function_1)
+  :JMP(finalizeExecution)
+function_1:
+  SP - 1 => SP
+  RR :MSTORE(SP)
+  C :MSTORE(SP - 1)
+  E :MSTORE(SP - 2)
+  B :MSTORE(SP - 3)
+  SP - 4 => SP
+  1n => B  ;; LoadConst32
+  FIXME: Inst::Cltz(Writable { reg: v199 }, Writable { reg: v197 }, Writable { reg: v198 }, v192, true, types::I32)
+  31n => B  ;; LoadConst32
+  B :ASSERT
+  SP + 4 => SP
+  $ => C :MLOAD(SP - 1)
+  $ => E :MLOAD(SP - 2)
+  $ => B :MLOAD(SP - 3)
+  $ => RR :MLOAD(SP)
+  SP + 1 => SP
+  :JMP(RR)
+finalizeExecution:
+  ${beforeLast()}  :JMPN(finalizeExecution)
+                   :JMP(start)
+INCLUDE "helpers/2-exp.zkasm"
\ No newline at end of file
diff --git a/cranelift/zkasm_data/spectest/i32/generated/clz_7.zkasm b/cranelift/zkasm_data/spectest/i32/generated/clz_7.zkasm
new file mode 100644
index 000000000000..cd17dc14b8ad
--- /dev/null
+++ b/cranelift/zkasm_data/spectest/i32/generated/clz_7.zkasm
@@ -0,0 +1,27 @@
+start:
+  0xffff => SP
+  zkPC + 2 => RR
+  :JMP(function_1)
+  :JMP(finalizeExecution)
+function_1:
+  SP - 1 => SP
+  RR :MSTORE(SP)
+  C :MSTORE(SP - 1)
+  E :MSTORE(SP - 2)
+  B :MSTORE(SP - 3)
+  SP - 4 => SP
+  2n => B  ;; LoadConst32
+  FIXME: Inst::Cltz(Writable { reg: v199 }, Writable { reg: v197 }, Writable { reg: v198 }, v192, true, types::I32)
+  30n => B  ;; LoadConst32
+  B :ASSERT
+  SP + 4 => SP
+  $ => C :MLOAD(SP - 1)
+  $ => E :MLOAD(SP - 2)
+  $ => B :MLOAD(SP - 3)
+  $ => RR :MLOAD(SP)
+  SP + 1 => SP
+  :JMP(RR)
+finalizeExecution:
+  ${beforeLast()}  :JMPN(finalizeExecution)
+                   :JMP(start)
+INCLUDE "helpers/2-exp.zkasm"
\ No newline at end of file
diff --git a/cranelift/zkasm_data/spectest/i32/generated/clz_8.zkasm b/cranelift/zkasm_data/spectest/i32/generated/clz_8.zkasm
new file mode 100644
index 000000000000..2394d0d2ddda
--- /dev/null
+++ b/cranelift/zkasm_data/spectest/i32/generated/clz_8.zkasm
@@ -0,0 +1,27 @@
+start:
+  0xffff => SP
+  zkPC + 2 => RR
+  :JMP(function_1)
+  :JMP(finalizeExecution)
+function_1:
+  SP - 1 => SP
+  RR :MSTORE(SP)
+  C :MSTORE(SP - 1)
+  E :MSTORE(SP - 2)
+  B :MSTORE(SP - 3)
+  SP - 4 => SP
+  2147483647n => B  ;; LoadConst32
+  FIXME: Inst::Cltz(Writable { reg: v199 }, Writable { reg: v197 }, Writable { reg: v198 }, v192, true, types::I32)
+  1n => B  ;; LoadConst32
+  B :ASSERT
+  SP + 4 => SP
+  $ => C :MLOAD(SP - 1)
+  $ => E :MLOAD(SP - 2)
+  $ => B :MLOAD(SP - 3)
+  $ => RR :MLOAD(SP)
+  SP + 1 => SP
+  :JMP(RR)
+finalizeExecution:
+  ${beforeLast()}  :JMPN(finalizeExecution)
+                   :JMP(start)
+INCLUDE "helpers/2-exp.zkasm"
\ No newline at end of file
diff --git a/cranelift/zkasm_data/spectest/i32/generated/ctz_1.zkasm b/cranelift/zkasm_data/spectest/i32/generated/ctz_1.zkasm
new file mode 100644
index 000000000000..a23400e98f48
--- /dev/null
+++ b/cranelift/zkasm_data/spectest/i32/generated/ctz_1.zkasm
@@ -0,0 +1,27 @@
+start:
+  0xffff => SP
+  zkPC + 2 => RR
+  :JMP(function_1)
+  :JMP(finalizeExecution)
+function_1:
+  SP - 1 => SP
+  RR :MSTORE(SP)
+  C :MSTORE(SP - 1)
+  E :MSTORE(SP - 2)
+  B :MSTORE(SP - 3)
+  SP - 4 => SP
+  4294967295n => B  ;; LoadConst32
+  FIXME: Inst::Cltz(Writable { reg: v199 }, Writable { reg: v197 }, Writable { reg: v198 }, v192, false, types::I32)
+  0n => B  ;; LoadConst32
+  B :ASSERT
+  SP + 4 => SP
+  $ => C :MLOAD(SP - 1)
+  $ => E :MLOAD(SP - 2)
+  $ => B :MLOAD(SP - 3)
+  $ => RR :MLOAD(SP)
+  SP + 1 => SP
+  :JMP(RR)
+finalizeExecution:
+  ${beforeLast()}  :JMPN(finalizeExecution)
+                   :JMP(start)
+INCLUDE "helpers/2-exp.zkasm"
\ No newline at end of file
diff --git a/cranelift/zkasm_data/spectest/i32/generated/ctz_2.zkasm b/cranelift/zkasm_data/spectest/i32/generated/ctz_2.zkasm
new file mode 100644
index 000000000000..b7fec6b5fd4e
--- /dev/null
+++ b/cranelift/zkasm_data/spectest/i32/generated/ctz_2.zkasm
@@ -0,0 +1,27 @@
+start:
+  0xffff => SP
+  zkPC + 2 => RR
+  :JMP(function_1)
+  :JMP(finalizeExecution)
+function_1:
+  SP - 1 => SP
+  RR :MSTORE(SP)
+  C :MSTORE(SP - 1)
+  E :MSTORE(SP - 2)
+  B :MSTORE(SP - 3)
+  SP - 4 => SP
+  0n => B  ;; LoadConst32
+  FIXME: Inst::Cltz(Writable { reg: v199 }, Writable { reg: v197 }, Writable { reg: v198 }, v192, false, types::I32)
+  32n => B  ;; LoadConst32
+  B :ASSERT
+  SP + 4 => SP
+  $ => C :MLOAD(SP - 1)
+  $ => E :MLOAD(SP - 2)
+  $ => B :MLOAD(SP - 3)
+  $ => RR :MLOAD(SP)
+  SP + 1 => SP
+  :JMP(RR)
+finalizeExecution:
+  ${beforeLast()}  :JMPN(finalizeExecution)
+                   :JMP(start)
+INCLUDE "helpers/2-exp.zkasm"
\ No newline at end of file
diff --git a/cranelift/zkasm_data/spectest/i32/generated/ctz_3.zkasm b/cranelift/zkasm_data/spectest/i32/generated/ctz_3.zkasm
new file mode 100644
index 000000000000..d8b8518932a5
--- /dev/null
+++ b/cranelift/zkasm_data/spectest/i32/generated/ctz_3.zkasm
@@ -0,0 +1,27 @@
+start:
+  0xffff => SP
+  zkPC + 2 => RR
+  :JMP(function_1)
+  :JMP(finalizeExecution)
+function_1:
+  SP - 1 => SP
+  RR :MSTORE(SP)
+  C :MSTORE(SP - 1)
+  E :MSTORE(SP - 2)
+  B :MSTORE(SP - 3)
+  SP - 4 => SP
+  32768n => B  ;; LoadConst32
+  FIXME: Inst::Cltz(Writable { reg: v199 }, Writable { reg: v197 }, Writable { reg: v198 }, v192, false, types::I32)
+  15n => B  ;; LoadConst32
+  B :ASSERT
+  SP + 4 => SP
+  $ => C :MLOAD(SP - 1)
+  $ => E :MLOAD(SP - 2)
+  $ => B :MLOAD(SP - 3)
+  $ => RR :MLOAD(SP)
+  SP + 1 => SP
+  :JMP(RR)
+finalizeExecution:
+  ${beforeLast()}  :JMPN(finalizeExecution)
+                   :JMP(start)
+INCLUDE "helpers/2-exp.zkasm"
\ No newline at end of file
diff --git a/cranelift/zkasm_data/spectest/i32/generated/ctz_4.zkasm b/cranelift/zkasm_data/spectest/i32/generated/ctz_4.zkasm
new file mode 100644
index 000000000000..adbff77b9404
--- /dev/null
+++ b/cranelift/zkasm_data/spectest/i32/generated/ctz_4.zkasm
@@ -0,0 +1,27 @@
+start:
+  0xffff => SP
+  zkPC + 2 => RR
+  :JMP(function_1)
+  :JMP(finalizeExecution)
+function_1:
+  SP - 1 => SP
+  RR :MSTORE(SP)
+  C :MSTORE(SP - 1)
+  E :MSTORE(SP - 2)
+  B :MSTORE(SP - 3)
+  SP - 4 => SP
+  65536n => B  ;; LoadConst32
+  FIXME: Inst::Cltz(Writable { reg: v199 }, Writable { reg: v197 }, Writable { reg: v198 }, v192, false, types::I32)
+  16n => B  ;; LoadConst32
+  B :ASSERT
+  SP + 4 => SP
+  $ => C :MLOAD(SP - 1)
+  $ => E :MLOAD(SP - 2)
+  $ => B :MLOAD(SP - 3)
+  $ => RR :MLOAD(SP)
+  SP + 1 => SP
+  :JMP(RR)
+finalizeExecution:
+  ${beforeLast()}  :JMPN(finalizeExecution)
+                   :JMP(start)
+INCLUDE "helpers/2-exp.zkasm"
\ No newline at end of file
diff --git a/cranelift/zkasm_data/spectest/i32/generated/ctz_5.zkasm b/cranelift/zkasm_data/spectest/i32/generated/ctz_5.zkasm
new file mode 100644
index 000000000000..eac8e5269ed2
--- /dev/null
+++ b/cranelift/zkasm_data/spectest/i32/generated/ctz_5.zkasm
@@ -0,0 +1,27 @@
+start:
+  0xffff => SP
+  zkPC + 2 => RR
+  :JMP(function_1)
+  :JMP(finalizeExecution)
+function_1:
+  SP - 1 => SP
+  RR :MSTORE(SP)
+  C :MSTORE(SP - 1)
+  E :MSTORE(SP - 2)
+  B :MSTORE(SP - 3)
+  SP - 4 => SP
+  2147483648n => B  ;; LoadConst32
+  FIXME: Inst::Cltz(Writable { reg: v199 }, Writable { reg: v197 }, Writable { reg: v198 }, v192, false, types::I32)
+  31n => B  ;; LoadConst32
+  B :ASSERT
+  SP + 4 => SP
+  $ => C :MLOAD(SP - 1)
+  $ => E :MLOAD(SP - 2)
+  $ => B :MLOAD(SP - 3)
+  $ => RR :MLOAD(SP)
+  SP + 1 => SP
+  :JMP(RR)
+finalizeExecution:
+  ${beforeLast()}  :JMPN(finalizeExecution)
+                   :JMP(start)
+INCLUDE "helpers/2-exp.zkasm"
\ No newline at end of file
diff --git a/cranelift/zkasm_data/spectest/i32/generated/ctz_6.zkasm b/cranelift/zkasm_data/spectest/i32/generated/ctz_6.zkasm
new file mode 100644
index 000000000000..4a8d3ad804b6
--- /dev/null
+++ b/cranelift/zkasm_data/spectest/i32/generated/ctz_6.zkasm
@@ -0,0 +1,27 @@
+start:
+  0xffff => SP
+  zkPC + 2 => RR
+  :JMP(function_1)
+  :JMP(finalizeExecution)
+function_1:
+  SP - 1 => SP
+  RR :MSTORE(SP)
+  C :MSTORE(SP - 1)
+  E :MSTORE(SP - 2)
+  B :MSTORE(SP - 3)
+  SP - 4 => SP
+  2147483647n => B  ;; LoadConst32
+  FIXME: Inst::Cltz(Writable { reg: v199 }, Writable { reg: v197 }, Writable { reg: v198 }, v192, false, types::I32)
+  0n => B  ;; LoadConst32
+  B :ASSERT
+  SP + 4 => SP
+  $ => C :MLOAD(SP - 1)
+  $ => E :MLOAD(SP - 2)
+  $ => B :MLOAD(SP - 3)
+  $ => RR :MLOAD(SP)
+  SP + 1 => SP
+  :JMP(RR)
+finalizeExecution:
+  ${beforeLast()}  :JMPN(finalizeExecution)
+                   :JMP(start)
+INCLUDE "helpers/2-exp.zkasm"
\ No newline at end of file
diff --git a/cranelift/zkasm_data/spectest/i32/state.csv b/cranelift/zkasm_data/spectest/i32/state.csv
index 26954c3b5209..c52ad7d23688 100644
--- a/cranelift/zkasm_data/spectest/i32/state.csv
+++ b/cranelift/zkasm_data/spectest/i32/state.csv
@@ -15,20 +15,20 @@ and_5,pass,18
 and_6,pass,18
 and_7,pass,18
 and_8,pass,18
-clz_1,compilation failed,
-clz_2,compilation failed,
-clz_3,compilation failed,
-clz_4,compilation failed,
-clz_5,compilation failed,
-clz_6,compilation failed,
-clz_7,compilation failed,
-clz_8,compilation failed,
-ctz_1,compilation failed,
-ctz_2,compilation failed,
-ctz_3,compilation failed,
-ctz_4,compilation failed,
-ctz_5,compilation failed,
-ctz_6,compilation failed,
+clz_1,runtime error,
+clz_2,runtime error,
+clz_3,runtime error,
+clz_4,runtime error,
+clz_5,runtime error,
+clz_6,runtime error,
+clz_7,runtime error,
+clz_8,runtime error,
+ctz_1,runtime error,
+ctz_2,runtime error,
+ctz_3,runtime error,
+ctz_4,runtime error,
+ctz_5,runtime error,
+ctz_6,runtime error,
 div_s_1,pass,27
 div_s_10,runtime error,
 div_s_11,pass,27
diff --git a/cranelift/zkasm_data/spectest/i64/generated/clz_1.zkasm b/cranelift/zkasm_data/spectest/i64/generated/clz_1.zkasm
new file mode 100644
index 000000000000..51182265def9
--- /dev/null
+++ b/cranelift/zkasm_data/spectest/i64/generated/clz_1.zkasm
@@ -0,0 +1,27 @@
+start:
+  0xffff => SP
+  zkPC + 2 => RR
+  :JMP(function_1)
+  :JMP(finalizeExecution)
+function_1:
+  SP - 1 => SP
+  RR :MSTORE(SP)
+  C :MSTORE(SP - 1)
+  E :MSTORE(SP - 2)
+  B :MSTORE(SP - 3)
+  SP - 4 => SP
+  18446744073709551615n => B  ;; LoadConst64
+  FIXME: Inst::Cltz(Writable { reg: v199 }, Writable { reg: v197 }, Writable { reg: v198 }, v192, true, types::I64)
+  0n => B  ;; LoadConst64
+  B :ASSERT
+  SP + 4 => SP
+  $ => C :MLOAD(SP - 1)
+  $ => E :MLOAD(SP - 2)
+  $ => B :MLOAD(SP - 3)
+  $ => RR :MLOAD(SP)
+  SP + 1 => SP
+  :JMP(RR)
+finalizeExecution:
+  ${beforeLast()}  :JMPN(finalizeExecution)
+                   :JMP(start)
+INCLUDE "helpers/2-exp.zkasm"
\ No newline at end of file
diff --git a/cranelift/zkasm_data/spectest/i64/generated/clz_2.zkasm b/cranelift/zkasm_data/spectest/i64/generated/clz_2.zkasm
new file mode 100644
index 000000000000..a7dbff492554
--- /dev/null
+++ b/cranelift/zkasm_data/spectest/i64/generated/clz_2.zkasm
@@ -0,0 +1,27 @@
+start:
+  0xffff => SP
+  zkPC + 2 => RR
+  :JMP(function_1)
+  :JMP(finalizeExecution)
+function_1:
+  SP - 1 => SP
+  RR :MSTORE(SP)
+  C :MSTORE(SP - 1)
+  E :MSTORE(SP - 2)
+  B :MSTORE(SP - 3)
+  SP - 4 => SP
+  0n => B  ;; LoadConst64
+  FIXME: Inst::Cltz(Writable { reg: v199 }, Writable { reg: v197 }, Writable { reg: v198 }, v192, true, types::I64)
+  64n => B  ;; LoadConst64
+  B :ASSERT
+  SP + 4 => SP
+  $ => C :MLOAD(SP - 1)
+  $ => E :MLOAD(SP - 2)
+  $ => B :MLOAD(SP - 3)
+  $ => RR :MLOAD(SP)
+  SP + 1 => SP
+  :JMP(RR)
+finalizeExecution:
+  ${beforeLast()}  :JMPN(finalizeExecution)
+                   :JMP(start)
+INCLUDE "helpers/2-exp.zkasm"
\ No newline at end of file
diff --git a/cranelift/zkasm_data/spectest/i64/generated/clz_3.zkasm b/cranelift/zkasm_data/spectest/i64/generated/clz_3.zkasm
new file mode 100644
index 000000000000..be6d943f2bc6
--- /dev/null
+++ b/cranelift/zkasm_data/spectest/i64/generated/clz_3.zkasm
@@ -0,0 +1,27 @@
+start:
+  0xffff => SP
+  zkPC + 2 => RR
+  :JMP(function_1)
+  :JMP(finalizeExecution)
+function_1:
+  SP - 1 => SP
+  RR :MSTORE(SP)
+  C :MSTORE(SP - 1)
+  E :MSTORE(SP - 2)
+  B :MSTORE(SP - 3)
+  SP - 4 => SP
+  32768n => B  ;; LoadConst64
+  FIXME: Inst::Cltz(Writable { reg: v199 }, Writable { reg: v197 }, Writable { reg: v198 }, v192, true, types::I64)
+  48n => B  ;; LoadConst64
+  B :ASSERT
+  SP + 4 => SP
+  $ => C :MLOAD(SP - 1)
+  $ => E :MLOAD(SP - 2)
+  $ => B :MLOAD(SP - 3)
+  $ => RR :MLOAD(SP)
+  SP + 1 => SP
+  :JMP(RR)
+finalizeExecution:
+  ${beforeLast()}  :JMPN(finalizeExecution)
+                   :JMP(start)
+INCLUDE "helpers/2-exp.zkasm"
\ No newline at end of file
diff --git a/cranelift/zkasm_data/spectest/i64/generated/clz_4.zkasm b/cranelift/zkasm_data/spectest/i64/generated/clz_4.zkasm
new file mode 100644
index 000000000000..b88fcb9eed9d
--- /dev/null
+++ b/cranelift/zkasm_data/spectest/i64/generated/clz_4.zkasm
@@ -0,0 +1,27 @@
+start:
+  0xffff => SP
+  zkPC + 2 => RR
+  :JMP(function_1)
+  :JMP(finalizeExecution)
+function_1:
+  SP - 1 => SP
+  RR :MSTORE(SP)
+  C :MSTORE(SP - 1)
+  E :MSTORE(SP - 2)
+  B :MSTORE(SP - 3)
+  SP - 4 => SP
+  255n => B  ;; LoadConst64
+  FIXME: Inst::Cltz(Writable { reg: v199 }, Writable { reg: v197 }, Writable { reg: v198 }, v192, true, types::I64)
+  56n => B  ;; LoadConst64
+  B :ASSERT
+  SP + 4 => SP
+  $ => C :MLOAD(SP - 1)
+  $ => E :MLOAD(SP - 2)
+  $ => B :MLOAD(SP - 3)
+  $ => RR :MLOAD(SP)
+  SP + 1 => SP
+  :JMP(RR)
+finalizeExecution:
+  ${beforeLast()}  :JMPN(finalizeExecution)
+                   :JMP(start)
+INCLUDE "helpers/2-exp.zkasm"
\ No newline at end of file
diff --git a/cranelift/zkasm_data/spectest/i64/generated/clz_5.zkasm b/cranelift/zkasm_data/spectest/i64/generated/clz_5.zkasm
new file mode 100644
index 000000000000..51bb34c667f6
--- /dev/null
+++ b/cranelift/zkasm_data/spectest/i64/generated/clz_5.zkasm
@@ -0,0 +1,27 @@
+start:
+  0xffff => SP
+  zkPC + 2 => RR
+  :JMP(function_1)
+  :JMP(finalizeExecution)
+function_1:
+  SP - 1 => SP
+  RR :MSTORE(SP)
+  C :MSTORE(SP - 1)
+  E :MSTORE(SP - 2)
+  B :MSTORE(SP - 3)
+  SP - 4 => SP
+  9223372036854775808n => B  ;; LoadConst64
+  FIXME: Inst::Cltz(Writable { reg: v199 }, Writable { reg: v197 }, Writable { reg: v198 }, v192, true, types::I64)
+  0n => B  ;; LoadConst64
+  B :ASSERT
+  SP + 4 => SP
+  $ => C :MLOAD(SP - 1)
+  $ => E :MLOAD(SP - 2)
+  $ => B :MLOAD(SP - 3)
+  $ => RR :MLOAD(SP)
+  SP + 1 => SP
+  :JMP(RR)
+finalizeExecution:
+  ${beforeLast()}  :JMPN(finalizeExecution)
+                   :JMP(start)
+INCLUDE "helpers/2-exp.zkasm"
\ No newline at end of file
diff --git a/cranelift/zkasm_data/spectest/i64/generated/clz_6.zkasm b/cranelift/zkasm_data/spectest/i64/generated/clz_6.zkasm
new file mode 100644
index 000000000000..ebfb499011f9
--- /dev/null
+++ b/cranelift/zkasm_data/spectest/i64/generated/clz_6.zkasm
@@ -0,0 +1,27 @@
+start:
+  0xffff => SP
+  zkPC + 2 => RR
+  :JMP(function_1)
+  :JMP(finalizeExecution)
+function_1:
+  SP - 1 => SP
+  RR :MSTORE(SP)
+  C :MSTORE(SP - 1)
+  E :MSTORE(SP - 2)
+  B :MSTORE(SP - 3)
+  SP - 4 => SP
+  1n => B  ;; LoadConst64
+  FIXME: Inst::Cltz(Writable { reg: v199 }, Writable { reg: v197 }, Writable { reg: v198 }, v192, true, types::I64)
+  63n => B  ;; LoadConst64
+  B :ASSERT
+  SP + 4 => SP
+  $ => C :MLOAD(SP - 1)
+  $ => E :MLOAD(SP - 2)
+  $ => B :MLOAD(SP - 3)
+  $ => RR :MLOAD(SP)
+  SP + 1 => SP
+  :JMP(RR)
+finalizeExecution:
+  ${beforeLast()}  :JMPN(finalizeExecution)
+                   :JMP(start)
+INCLUDE "helpers/2-exp.zkasm"
\ No newline at end of file
diff --git a/cranelift/zkasm_data/spectest/i64/generated/clz_7.zkasm b/cranelift/zkasm_data/spectest/i64/generated/clz_7.zkasm
new file mode 100644
index 000000000000..0131eb5f939b
--- /dev/null
+++ b/cranelift/zkasm_data/spectest/i64/generated/clz_7.zkasm
@@ -0,0 +1,27 @@
+start:
+  0xffff => SP
+  zkPC + 2 => RR
+  :JMP(function_1)
+  :JMP(finalizeExecution)
+function_1:
+  SP - 1 => SP
+  RR :MSTORE(SP)
+  C :MSTORE(SP - 1)
+  E :MSTORE(SP - 2)
+  B :MSTORE(SP - 3)
+  SP - 4 => SP
+  2n => B  ;; LoadConst64
+  FIXME: Inst::Cltz(Writable { reg: v199 }, Writable { reg: v197 }, Writable { reg: v198 }, v192, true, types::I64)
+  62n => B  ;; LoadConst64
+  B :ASSERT
+  SP + 4 => SP
+  $ => C :MLOAD(SP - 1)
+  $ => E :MLOAD(SP - 2)
+  $ => B :MLOAD(SP - 3)
+  $ => RR :MLOAD(SP)
+  SP + 1 => SP
+  :JMP(RR)
+finalizeExecution:
+  ${beforeLast()}  :JMPN(finalizeExecution)
+                   :JMP(start)
+INCLUDE "helpers/2-exp.zkasm"
\ No newline at end of file
diff --git a/cranelift/zkasm_data/spectest/i64/generated/clz_8.zkasm b/cranelift/zkasm_data/spectest/i64/generated/clz_8.zkasm
new file mode 100644
index 000000000000..c5b75d2126a0
--- /dev/null
+++ b/cranelift/zkasm_data/spectest/i64/generated/clz_8.zkasm
@@ -0,0 +1,27 @@
+start:
+  0xffff => SP
+  zkPC + 2 => RR
+  :JMP(function_1)
+  :JMP(finalizeExecution)
+function_1:
+  SP - 1 => SP
+  RR :MSTORE(SP)
+  C :MSTORE(SP - 1)
+  E :MSTORE(SP - 2)
+  B :MSTORE(SP - 3)
+  SP - 4 => SP
+  9223372036854775807n => B  ;; LoadConst64
+  FIXME: Inst::Cltz(Writable { reg: v199 }, Writable { reg: v197 }, Writable { reg: v198 }, v192, true, types::I64)
+  1n => B  ;; LoadConst64
+  B :ASSERT
+  SP + 4 => SP
+  $ => C :MLOAD(SP - 1)
+  $ => E :MLOAD(SP - 2)
+  $ => B :MLOAD(SP - 3)
+  $ => RR :MLOAD(SP)
+  SP + 1 => SP
+  :JMP(RR)
+finalizeExecution:
+  ${beforeLast()}  :JMPN(finalizeExecution)
+                   :JMP(start)
+INCLUDE "helpers/2-exp.zkasm"
\ No newline at end of file
diff --git a/cranelift/zkasm_data/spectest/i64/generated/ctz_1.zkasm b/cranelift/zkasm_data/spectest/i64/generated/ctz_1.zkasm
new file mode 100644
index 000000000000..2f5d70a582f3
--- /dev/null
+++ b/cranelift/zkasm_data/spectest/i64/generated/ctz_1.zkasm
@@ -0,0 +1,27 @@
+start:
+  0xffff => SP
+  zkPC + 2 => RR
+  :JMP(function_1)
+  :JMP(finalizeExecution)
+function_1:
+  SP - 1 => SP
+  RR :MSTORE(SP)
+  C :MSTORE(SP - 1)
+  E :MSTORE(SP - 2)
+  B :MSTORE(SP - 3)
+  SP - 4 => SP
+  18446744073709551615n => B  ;; LoadConst64
+  FIXME: Inst::Cltz(Writable { reg: v199 }, Writable { reg: v197 }, Writable { reg: v198 }, v192, false, types::I64)
+  0n => B  ;; LoadConst64
+  B :ASSERT
+  SP + 4 => SP
+  $ => C :MLOAD(SP - 1)
+  $ => E :MLOAD(SP - 2)
+  $ => B :MLOAD(SP - 3)
+  $ => RR :MLOAD(SP)
+  SP + 1 => SP
+  :JMP(RR)
+finalizeExecution:
+  ${beforeLast()}  :JMPN(finalizeExecution)
+                   :JMP(start)
+INCLUDE "helpers/2-exp.zkasm"
\ No newline at end of file
diff --git a/cranelift/zkasm_data/spectest/i64/generated/ctz_2.zkasm b/cranelift/zkasm_data/spectest/i64/generated/ctz_2.zkasm
new file mode 100644
index 000000000000..722a6d41997d
--- /dev/null
+++ b/cranelift/zkasm_data/spectest/i64/generated/ctz_2.zkasm
@@ -0,0 +1,27 @@
+start:
+  0xffff => SP
+  zkPC + 2 => RR
+  :JMP(function_1)
+  :JMP(finalizeExecution)
+function_1:
+  SP - 1 => SP
+  RR :MSTORE(SP)
+  C :MSTORE(SP - 1)
+  E :MSTORE(SP - 2)
+  B :MSTORE(SP - 3)
+  SP - 4 => SP
+  0n => B  ;; LoadConst64
+  FIXME: Inst::Cltz(Writable { reg: v199 }, Writable { reg: v197 }, Writable { reg: v198 }, v192, false, types::I64)
+  64n => B  ;; LoadConst64
+  B :ASSERT
+  SP + 4 => SP
+  $ => C :MLOAD(SP - 1)
+  $ => E :MLOAD(SP - 2)
+  $ => B :MLOAD(SP - 3)
+  $ => RR :MLOAD(SP)
+  SP + 1 => SP
+  :JMP(RR)
+finalizeExecution:
+  ${beforeLast()}  :JMPN(finalizeExecution)
+                   :JMP(start)
+INCLUDE "helpers/2-exp.zkasm"
\ No newline at end of file
diff --git a/cranelift/zkasm_data/spectest/i64/generated/ctz_3.zkasm b/cranelift/zkasm_data/spectest/i64/generated/ctz_3.zkasm
new file mode 100644
index 000000000000..62786f4f96d4
--- /dev/null
+++ b/cranelift/zkasm_data/spectest/i64/generated/ctz_3.zkasm
@@ -0,0 +1,27 @@
+start:
+  0xffff => SP
+  zkPC + 2 => RR
+  :JMP(function_1)
+  :JMP(finalizeExecution)
+function_1:
+  SP - 1 => SP
+  RR :MSTORE(SP)
+  C :MSTORE(SP - 1)
+  E :MSTORE(SP - 2)
+  B :MSTORE(SP - 3)
+  SP - 4 => SP
+  32768n => B  ;; LoadConst64
+  FIXME: Inst::Cltz(Writable { reg: v199 }, Writable { reg: v197 }, Writable { reg: v198 }, v192, false, types::I64)
+  15n => B  ;; LoadConst64
+  B :ASSERT
+  SP + 4 => SP
+  $ => C :MLOAD(SP - 1)
+  $ => E :MLOAD(SP - 2)
+  $ => B :MLOAD(SP - 3)
+  $ => RR :MLOAD(SP)
+  SP + 1 => SP
+  :JMP(RR)
+finalizeExecution:
+  ${beforeLast()}  :JMPN(finalizeExecution)
+                   :JMP(start)
+INCLUDE "helpers/2-exp.zkasm"
\ No newline at end of file
diff --git a/cranelift/zkasm_data/spectest/i64/generated/ctz_4.zkasm b/cranelift/zkasm_data/spectest/i64/generated/ctz_4.zkasm
new file mode 100644
index 000000000000..48fb822ee106
--- /dev/null
+++ b/cranelift/zkasm_data/spectest/i64/generated/ctz_4.zkasm
@@ -0,0 +1,27 @@
+start:
+  0xffff => SP
+  zkPC + 2 => RR
+  :JMP(function_1)
+  :JMP(finalizeExecution)
+function_1:
+  SP - 1 => SP
+  RR :MSTORE(SP)
+  C :MSTORE(SP - 1)
+  E :MSTORE(SP - 2)
+  B :MSTORE(SP - 3)
+  SP - 4 => SP
+  65536n => B  ;; LoadConst64
+  FIXME: Inst::Cltz(Writable { reg: v199 }, Writable { reg: v197 }, Writable { reg: v198 }, v192, false, types::I64)
+  16n => B  ;; LoadConst64
+  B :ASSERT
+  SP + 4 => SP
+  $ => C :MLOAD(SP - 1)
+  $ => E :MLOAD(SP - 2)
+  $ => B :MLOAD(SP - 3)
+  $ => RR :MLOAD(SP)
+  SP + 1 => SP
+  :JMP(RR)
+finalizeExecution:
+  ${beforeLast()}  :JMPN(finalizeExecution)
+                   :JMP(start)
+INCLUDE "helpers/2-exp.zkasm"
\ No newline at end of file
diff --git a/cranelift/zkasm_data/spectest/i64/generated/ctz_5.zkasm b/cranelift/zkasm_data/spectest/i64/generated/ctz_5.zkasm
new file mode 100644
index 000000000000..760a1d97a899
--- /dev/null
+++ b/cranelift/zkasm_data/spectest/i64/generated/ctz_5.zkasm
@@ -0,0 +1,27 @@
+start:
+  0xffff => SP
+  zkPC + 2 => RR
+  :JMP(function_1)
+  :JMP(finalizeExecution)
+function_1:
+  SP - 1 => SP
+  RR :MSTORE(SP)
+  C :MSTORE(SP - 1)
+  E :MSTORE(SP - 2)
+  B :MSTORE(SP - 3)
+  SP - 4 => SP
+  9223372036854775808n => B  ;; LoadConst64
+  FIXME: Inst::Cltz(Writable { reg: v199 }, Writable { reg: v197 }, Writable { reg: v198 }, v192, false, types::I64)
+  63n => B  ;; LoadConst64
+  B :ASSERT
+  SP + 4 => SP
+  $ => C :MLOAD(SP - 1)
+  $ => E :MLOAD(SP - 2)
+  $ => B :MLOAD(SP - 3)
+  $ => RR :MLOAD(SP)
+  SP + 1 => SP
+  :JMP(RR)
+finalizeExecution:
+  ${beforeLast()}  :JMPN(finalizeExecution)
+                   :JMP(start)
+INCLUDE "helpers/2-exp.zkasm"
\ No newline at end of file
diff --git a/cranelift/zkasm_data/spectest/i64/generated/ctz_6.zkasm b/cranelift/zkasm_data/spectest/i64/generated/ctz_6.zkasm
new file mode 100644
index 000000000000..4ec08fe14f97
--- /dev/null
+++ b/cranelift/zkasm_data/spectest/i64/generated/ctz_6.zkasm
@@ -0,0 +1,27 @@
+start:
+  0xffff => SP
+  zkPC + 2 => RR
+  :JMP(function_1)
+  :JMP(finalizeExecution)
+function_1:
+  SP - 1 => SP
+  RR :MSTORE(SP)
+  C :MSTORE(SP - 1)
+  E :MSTORE(SP - 2)
+  B :MSTORE(SP - 3)
+  SP - 4 => SP
+  9223372036854775807n => B  ;; LoadConst64
+  FIXME: Inst::Cltz(Writable { reg: v199 }, Writable { reg: v197 }, Writable { reg: v198 }, v192, false, types::I64)
+  0n => B  ;; LoadConst64
+  B :ASSERT
+  SP + 4 => SP
+  $ => C :MLOAD(SP - 1)
+  $ => E :MLOAD(SP - 2)
+  $ => B :MLOAD(SP - 3)
+  $ => RR :MLOAD(SP)
+  SP + 1 => SP
+  :JMP(RR)
+finalizeExecution:
+  ${beforeLast()}  :JMPN(finalizeExecution)
+                   :JMP(start)
+INCLUDE "helpers/2-exp.zkasm"
\ No newline at end of file
diff --git a/cranelift/zkasm_data/spectest/i64/state.csv b/cranelift/zkasm_data/spectest/i64/state.csv
index a10afb02cb6f..d84969e9a320 100644
--- a/cranelift/zkasm_data/spectest/i64/state.csv
+++ b/cranelift/zkasm_data/spectest/i64/state.csv
@@ -15,20 +15,20 @@ and_5,pass,18
 and_6,pass,18
 and_7,pass,18
 and_8,pass,18
-clz_1,compilation failed,
-clz_2,compilation failed,
-clz_3,compilation failed,
-clz_4,compilation failed,
-clz_5,compilation failed,
-clz_6,compilation failed,
-clz_7,compilation failed,
-clz_8,compilation failed,
-ctz_1,compilation failed,
-ctz_2,compilation failed,
-ctz_3,compilation failed,
-ctz_4,compilation failed,
-ctz_5,compilation failed,
-ctz_6,compilation failed,
+clz_1,runtime error,
+clz_2,runtime error,
+clz_3,runtime error,
+clz_4,runtime error,
+clz_5,runtime error,
+clz_6,runtime error,
+clz_7,runtime error,
+clz_8,runtime error,
+ctz_1,runtime error,
+ctz_2,runtime error,
+ctz_3,runtime error,
+ctz_4,runtime error,
+ctz_5,runtime error,
+ctz_6,runtime error,
 div_s_1,pass,27
 div_s_10,runtime error,
 div_s_11,pass,27