EVM gas for memory tiny optimization (#1578)

* EVM bin benches

* Optimizing mem gas cost

* Removing overflow_div since it's not used

* More benchmarks

evmbin/benches/mod.rs

@@ -0,0 +1,85 @@
+// Copyright 2015, 2016 Ethcore (UK) Ltd.
+// This file is part of Parity.
+
+// Parity is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+
+// Parity is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+
+// You should have received a copy of the GNU General Public License
+// along with Parity.  If not, see <http://www.gnu.org/licenses/>.
+
+//! benchmarking for EVM
+//! should be started with:
+//! ```bash
+//! multirust run nightly cargo bench
+//! ```
+
+#![feature(test)]
+
+extern crate test;
+extern crate ethcore;
+extern crate evm;
+extern crate ethcore_util;
+extern crate rustc_serialize;
+
+use self::test::{Bencher, black_box};
+
+use evm::run_vm;
+use ethcore::action_params::ActionParams;
+use ethcore_util::{U256, Uint};
+use rustc_serialize::hex::FromHex;
+
+#[bench]
+fn simple_loop_usize(b: &mut Bencher) {
+	simple_loop(U256::from(::std::usize::MAX), b)
+}
+
+#[bench]
+fn simple_loop_u256(b: &mut Bencher) {
+	simple_loop(!U256::zero(), b)
+}
+
+fn simple_loop(gas: U256, b: &mut Bencher) {
+	let code = black_box(
+		"606060405260005b620042408112156019575b6001016007565b600081905550600680602b6000396000f3606060405200".from_hex().unwrap()
+	);
+
+	b.iter(|| {
+		let mut params = ActionParams::default();
+		params.gas = gas;
+		params.code = Some(code.clone());
+
+		run_vm(params)
+	});
+}
+
+#[bench]
+fn rng_usize(b: &mut Bencher) {
+	rng(U256::from(::std::usize::MAX), b)
+}
+
+#[bench]
+fn rng_u256(b: &mut Bencher) {
+	rng(!U256::zero(), b)
+}
+
+fn rng(gas: U256, b: &mut Bencher) {
+	let code = black_box(
+		"6060604052600360056007600b60005b62004240811215607f5767ffe7649d5eca84179490940267f47ed85c4b9a6379019367f8e5dd9a5c994bba9390930267f91d87e4b8b74e55019267ff97f6f3b29cda529290920267f393ada8dd75c938019167fe8d437c45bb3735830267f47d9a7b5428ffec019150600101600f565b838518831882186000555050505050600680609a6000396000f3606060405200".from_hex().unwrap()
+	);
+
+	b.iter(|| {
+		let mut params = ActionParams::default();
+		params.gas = gas;
+		params.code = Some(code.clone());
+
+		run_vm(params)
+	});
+}
+