refactor(stdlib): optimized emptyCell() and emptySlice()

src/stdlib/stdlib/std/internal/cells.tact

@@ -467,12 +467,12 @@ inline extends fun asCell(self: Builder): Cell {
     return self.endCell();
 }
 
-inline fun emptyCell(): Cell {
-    return beginCell().endCell();
+asm fun emptyCell(): Cell {
+    <b b> PUSHREF // Pure Fift: "<b" creates a builder, "b>" turns it into a cell at compile time
 }
 
-inline fun emptySlice(): Slice {
-    return emptyCell().asSlice();
+asm fun emptySlice(): Slice {
+    b{} PUSHSLICE
 }
 
 /// Struct for holding values computed by the `Cell.computeDataSize()` and `Slice.computeDataSize()` extension functions. Available since Tact 1.6.0.

src/test/benchmarks/__snapshots__/benchmarks.spec.ts.snap

@@ -1,9 +1,13 @@
 // Jest Snapshot v1, https://goo.gl/fbAQLP
 
-exports[`benchmarks benchmark functions: code size 1`] = `211`;
+exports[`benchmarks benchmark cells creation: gas used emptyCell 1`] = `931n`;
 
-exports[`benchmarks benchmark functions: gas used 1`] = `2769n`;
+exports[`benchmarks benchmark cells creation: gas used emptySlice 1`] = `1035n`;
 
-exports[`benchmarks benchmark readFwdFee: code size 1`] = `157`;
+exports[`benchmarks benchmark functions: code size 1`] = `227`;
 
-exports[`benchmarks benchmark readFwdFee: gas used 1`] = `2799n`;
+exports[`benchmarks benchmark functions: gas used 1`] = `2869n`;
+
+exports[`benchmarks benchmark readFwdFee: code size 1`] = `173`;
+
+exports[`benchmarks benchmark readFwdFee: gas used 1`] = `2899n`;

src/test/benchmarks/benchmarks.spec.ts

@@ -16,6 +16,7 @@ import { Sha256Big } from "./contracts/output/benchmark_sha256_big_Sha256Big";
 import { Sha256AsSlice } from "./contracts/output/benchmark_sha256_as_slice_Sha256AsSlice";
 import { Forward } from "./contracts/output/forward_Forward";
 import "@ton/test-utils";
+import { cellsCreation } from "./contracts/output/cells_cellsCreation";
 import { getUsedGas } from "./util";
 
 function measureGas(txs: BlockchainTransaction[]) {
@@ -164,4 +165,22 @@ describe("benchmarks", () => {
             await hashStringAsSLice(sha256AsSlice, "hello world".repeat(10)),
         ).toEqual(2516n);
     });
+    it("benchmark cells creation", async () => {
+        const testContract = blockchain.openContract(
+            await cellsCreation.fromInit(),
+        );
+        await testContract.send(
+            treasure.getSender(),
+            { value: toNano(1) },
+            beginCell().asSlice(),
+        );
+        const gasUsed1 = (
+            await blockchain.runGetMethod(testContract.address, "getEmptyCell")
+        ).gasUsed;
+        expect(gasUsed1).toMatchSnapshot("gas used emptyCell");
+        const gasUsed2 = (
+            await blockchain.runGetMethod(testContract.address, "getEmptySlice")
+        ).gasUsed;
+        expect(gasUsed2).toMatchSnapshot("gas used emptySlice");
+    });
 });

src/test/benchmarks/contracts/cells.tact

@@ -0,0 +1,11 @@
+contract cellsCreation {
+    receive(msg: Slice) {
+
+    }
+    get fun getEmptyCell(): Cell {
+        return emptyCell();
+    }
+    get fun getEmptySlice(): Slice {
+        return emptySlice();
+    }
+}