diff --git a/test/libsolidity/gasTests/abiv2.sol b/test/libsolidity/gasTests/abiv2.sol
index 6fa822fade47..ba86bac7ed51 100644
--- a/test/libsolidity/gasTests/abiv2.sol
+++ b/test/libsolidity/gasTests/abiv2.sol
@@ -12,6 +12,8 @@ contract C {
     function f7(uint[31] memory, string[20] memory, C, address) public returns (bytes[] memory, uint16[] memory) {}
     function f8(uint[32] memory, string[] memory, uint32, address) public returns (uint[] memory, uint16[] memory) {}
 }
+// ====
+// bytecodeFormat: legacy
 // ----
 // creation:
 //   codeDepositCost: 1208000
diff --git a/test/libsolidity/gasTests/abiv2_optimised.sol b/test/libsolidity/gasTests/abiv2_optimised.sol
index 2989c1acd8f9..a005a67ef857 100644
--- a/test/libsolidity/gasTests/abiv2_optimised.sol
+++ b/test/libsolidity/gasTests/abiv2_optimised.sol
@@ -13,6 +13,7 @@ contract C {
     function f8(uint[32] memory, string[] memory, uint32, address) public returns (uint[] memory, uint16[] memory) {}
 }
 // ====
+// bytecodeFormat: legacy
 // optimize: true
 // optimize-yul: true
 // ----
diff --git a/test/libsolidity/gasTests/data_storage.sol b/test/libsolidity/gasTests/data_storage.sol
index 0d24ef505273..1dc43a21b302 100644
--- a/test/libsolidity/gasTests/data_storage.sol
+++ b/test/libsolidity/gasTests/data_storage.sol
@@ -11,6 +11,8 @@ contract C {
         require(false, "12345678901234567890123456789012123456789012345678901234567890123");
     }
 }
+// ====
+// bytecodeFormat: legacy
 // ----
 // creation:
 //   codeDepositCost: 377800
diff --git a/test/libsolidity/gasTests/dispatch_large.sol b/test/libsolidity/gasTests/dispatch_large.sol
index e1cce4acd764..c816f397a0b6 100644
--- a/test/libsolidity/gasTests/dispatch_large.sol
+++ b/test/libsolidity/gasTests/dispatch_large.sol
@@ -22,6 +22,8 @@ contract Large {
     function g9(uint x) public payable returns (uint) { b[uint8(msg.data[8])] = x; }
     function g0(uint x) public payable returns (uint) { require(x > 10); }
 }
+// ====
+// bytecodeFormat: legacy
 // ----
 // creation:
 //   codeDepositCost: 618400
diff --git a/test/libsolidity/gasTests/dispatch_large_optimised.sol b/test/libsolidity/gasTests/dispatch_large_optimised.sol
index 83e55c1a9c1e..36c6ae9d4ecc 100644
--- a/test/libsolidity/gasTests/dispatch_large_optimised.sol
+++ b/test/libsolidity/gasTests/dispatch_large_optimised.sol
@@ -23,6 +23,7 @@ contract Large {
     function g0(uint x) public payable returns (uint) { require(x > 10); }
 }
 // ====
+// bytecodeFormat: legacy
 // optimize: true
 // optimize-runs: 2
 // ----
diff --git a/test/libsolidity/gasTests/dispatch_medium.sol b/test/libsolidity/gasTests/dispatch_medium.sol
index 6bf8f89394fa..6227782c001b 100644
--- a/test/libsolidity/gasTests/dispatch_medium.sol
+++ b/test/libsolidity/gasTests/dispatch_medium.sol
@@ -9,6 +9,8 @@ contract Medium {
     function g9(uint x) public payable returns (uint) { b[uint8(msg.data[8])] = x; }
     function g0(uint x) public payable returns (uint) { require(x > 10); }
 }
+// ====
+// bytecodeFormat: legacy
 // ----
 // creation:
 //   codeDepositCost: 259600
diff --git a/test/libsolidity/gasTests/dispatch_medium_optimised.sol b/test/libsolidity/gasTests/dispatch_medium_optimised.sol
index e921fcf125ba..3289d9437fb9 100644
--- a/test/libsolidity/gasTests/dispatch_medium_optimised.sol
+++ b/test/libsolidity/gasTests/dispatch_medium_optimised.sol
@@ -10,6 +10,8 @@ contract Medium {
     function g0(uint x) public payable returns (uint) { require(x > 10); }
 }
 // ====
+// bytecodeFormat: legacy
+// ====
 // optimize: true
 // optimize-runs: 2
 // ----
diff --git a/test/libsolidity/gasTests/dispatch_small.sol b/test/libsolidity/gasTests/dispatch_small.sol
index d2c391582ed5..5185ac23a483 100644
--- a/test/libsolidity/gasTests/dispatch_small.sol
+++ b/test/libsolidity/gasTests/dispatch_small.sol
@@ -4,6 +4,8 @@ contract Small {
     function f1(uint x) public returns (uint) { a = x; b[uint8(msg.data[0])] = x; }
     fallback () external payable {}
 }
+// ====
+// bytecodeFormat: legacy
 // ----
 // creation:
 //   codeDepositCost: 103800
diff --git a/test/libsolidity/gasTests/dispatch_small_optimised.sol b/test/libsolidity/gasTests/dispatch_small_optimised.sol
index e20e1d982427..1c4c01c353e8 100644
--- a/test/libsolidity/gasTests/dispatch_small_optimised.sol
+++ b/test/libsolidity/gasTests/dispatch_small_optimised.sol
@@ -7,6 +7,7 @@ contract Small {
 // ====
 // optimize: true
 // optimize-runs: 2
+// bytecodeFormat: legacy
 // ----
 // creation:
 //   codeDepositCost: 58200
diff --git a/test/libsolidity/gasTests/exp.sol b/test/libsolidity/gasTests/exp.sol
index 6ad4dd3bee43..13192f948f6f 100644
--- a/test/libsolidity/gasTests/exp.sol
+++ b/test/libsolidity/gasTests/exp.sol
@@ -15,6 +15,7 @@ contract C {
 	}
 }
 // ====
+// bytecodeFormat: legacy
 // optimize: false
 // optimize-yul: false
 // ----
diff --git a/test/libsolidity/gasTests/exp_optimized.sol b/test/libsolidity/gasTests/exp_optimized.sol
index 982fcd28feb9..0c86694dcc24 100644
--- a/test/libsolidity/gasTests/exp_optimized.sol
+++ b/test/libsolidity/gasTests/exp_optimized.sol
@@ -15,6 +15,7 @@ contract C {
 	}
 }
 // ====
+// bytecodeFormat: legacy
 // optimize: true
 // optimize-yul: true
 // ----
diff --git a/test/libsolidity/gasTests/storage_costs.sol b/test/libsolidity/gasTests/storage_costs.sol
index afb442ed7f97..a4f10eb5fea6 100644
--- a/test/libsolidity/gasTests/storage_costs.sol
+++ b/test/libsolidity/gasTests/storage_costs.sol
@@ -13,6 +13,7 @@ contract C {
 // ====
 // optimize: true
 // optimize-yul: true
+// bytecodeFormat: legacy
 // ----
 // creation:
 //   codeDepositCost: 25600