Merge pull request #12754 from ethereum/optimizerEqIszero

Some more peephole optimizer rules.

Author: ekpyron

Changelog.md

@@ -6,6 +6,7 @@ Language Features:
 
 Compiler Features:
 * JSON-AST: Added selector field for errors and events.
+ * Peephole Optimizer: Optimize comparisons in front of conditional jumps and conditional jumps across a single unconditional jump.
 
 Bugfixes:
  * Yul IR Code Generation: Optimize embedded creation code with correct settings. This fixes potential mismatches between the constructor code of a contract compiled in isolation and the bytecode in ``type(C).creationCode``, resp. the bytecode used for ``new C(...)``.

libevmasm/PeepholeOptimiser.cpp

@@ -233,6 +233,65 @@ struct IsZeroIsZeroJumpI: SimplePeepholeOptimizerMethod<IsZeroIsZeroJumpI>
 	}
 };
 
+struct EqIsZeroJumpI: SimplePeepholeOptimizerMethod<EqIsZeroJumpI>
+{
+	static size_t applySimple(
+		AssemblyItem const& _eq,
+		AssemblyItem const& _iszero,
+		AssemblyItem const& _pushTag,
+		AssemblyItem const& _jumpi,
+		std::back_insert_iterator<AssemblyItems> _out
+	)
+	{
+		if (
+			_eq == Instruction::EQ &&
+			_iszero == Instruction::ISZERO &&
+			_pushTag.type() == PushTag &&
+			_jumpi == Instruction::JUMPI
+		)
+		{
+			*_out = AssemblyItem(Instruction::SUB, _eq.location());
+			*_out = _pushTag;
+			*_out = _jumpi;
+			return true;
+		}
+		else
+			return false;
+	}
+};
+
+// push_tag_1 jumpi push_tag_2 jump tag_1: -> iszero push_tag_2 jumpi tag_1:
+struct DoubleJump: SimplePeepholeOptimizerMethod<DoubleJump>
+{
+	static size_t applySimple(
+		AssemblyItem const& _pushTag1,
+		AssemblyItem const& _jumpi,
+		AssemblyItem const& _pushTag2,
+		AssemblyItem const& _jump,
+		AssemblyItem const& _tag1,
+		std::back_insert_iterator<AssemblyItems> _out
+	)
+	{
+		if (
+			_pushTag1.type() == PushTag &&
+			_jumpi == Instruction::JUMPI &&
+			_pushTag2.type() == PushTag &&
+			_jump == Instruction::JUMP &&
+			_tag1.type() == Tag &&
+			_pushTag1.data() == _tag1.data()
+		)
+		{
+			*_out = AssemblyItem(Instruction::ISZERO, _jumpi.location());
+			*_out = _pushTag2;
+			*_out = _jumpi;
+			*_out = _tag1;
+			return true;
+		}
+		else
+			return false;
+	}
+};
+
 struct JumpToNext: SimplePeepholeOptimizerMethod<JumpToNext>
 {
 	static size_t applySimple(
@@ -372,7 +431,7 @@ bool PeepholeOptimiser::optimise()
 		applyMethods(
 			state,
 			PushPop(), OpPop(), DoublePush(), DoubleSwap(), CommutativeSwap(), SwapComparison(),
-			DupSwap(), IsZeroIsZeroJumpI(), JumpToNext(), UnreachableCode(),
+			DupSwap(), IsZeroIsZeroJumpI(), EqIsZeroJumpI(), DoubleJump(), JumpToNext(), UnreachableCode(),
 			TagConjunctions(), TruthyAnd(), Identity()
 		);
 	if (m_optimisedItems.size() < m_items.size() || (

test/cmdlineTests/optimizer_user_yul/output

@@ -58,10 +58,9 @@ tag_6:
     /* "optimizer_user_yul/input.sol":384:392  sload(5) */
   dup1
     /* "optimizer_user_yul/input.sol":376:509  for { } sload(5) { } {... */
-  tag_8
+  iszero
+  tag_6
   jumpi
-  jump(tag_6)
-tag_8:
     /* "optimizer_user_yul/input.sol":380:383  { } */
   pop
     /* "optimizer_user_yul/input.sol":340:513  {... */

test/libsolidity/semanticTests/abiEncoderV1/abi_decode_v2_storage.sol

@@ -25,5 +25,5 @@ contract C {
 // ----
 // f() -> 0x20, 0x8, 0x40, 0x3, 0x9, 0xa, 0xb
 // gas irOptimized: 203312
-// gas legacy: 206084
-// gas legacyOptimized: 203068
+// gas legacy: 206075
+// gas legacyOptimized: 203059

test/libsolidity/semanticTests/abiEncoderV1/abi_encode_calldata_slice.sol

@@ -61,9 +61,9 @@ contract C {
 // ----
 // test_bytes() ->
 // gas irOptimized: 371919
-// gas legacy: 418955
-// gas legacyOptimized: 326783
+// gas legacy: 416585
+// gas legacyOptimized: 322043
 // test_uint256() ->
 // gas irOptimized: 523001
-// gas legacy: 586784
-// gas legacyOptimized: 451529
+// gas legacy: 583100
+// gas legacyOptimized: 444161

test/libsolidity/semanticTests/abiEncoderV2/abi_encode_calldata_slice.sol

@@ -62,9 +62,9 @@ contract C {
 // ----
 // test_bytes() ->
 // gas irOptimized: 371919
-// gas legacy: 418955
-// gas legacyOptimized: 326783
+// gas legacy: 416585
+// gas legacyOptimized: 322043
 // test_uint256() ->
 // gas irOptimized: 523001
-// gas legacy: 586784
-// gas legacyOptimized: 451529
+// gas legacy: 583100
+// gas legacyOptimized: 444161

test/libsolidity/semanticTests/abiEncoderV2/calldata_array.sol

@@ -22,5 +22,5 @@ contract C {
 // f(uint256[][1]): 32, 32, 1, 42 -> true
 // f(uint256[][1]): 32, 32, 8, 421, 422, 423, 424, 425, 426, 427, 428 -> true
 // gas irOptimized: 171842
-// gas legacy: 141644
-// gas legacyOptimized: 121532
+// gas legacy: 140672
+// gas legacyOptimized: 119588

test/libsolidity/semanticTests/abiencodedecode/abi_decode_simple_storage.sol

@@ -12,5 +12,5 @@ contract C {
 // ----
 // f(bytes): 0x20, 0x80, 0x21, 0x40, 0x7, "abcdefg" -> 0x21, 0x40, 0x7, "abcdefg"
 // gas irOptimized: 135918
-// gas legacy: 137190
-// gas legacyOptimized: 136082
+// gas legacy: 137181
+// gas legacyOptimized: 136073

test/libsolidity/semanticTests/array/arrays_complex_from_and_to_storage.sol

@@ -14,7 +14,7 @@ contract Test {
 // compileViaYul: also
 // ----
 // set(uint24[3][]): 0x20, 0x06, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07, 0x08, 0x09, 0x0a, 0x0b, 0x0c, 0x0d, 0x0e, 0x0f, 0x10, 0x11, 0x12 -> 0x06
-// gas irOptimized: 189871
+// gas irOptimized: 189817
 // gas legacy: 211149
 // gas legacyOptimized: 206054
 // data(uint256,uint256): 0x02, 0x02 -> 0x09

test/libsolidity/semanticTests/array/byte_array_storage_layout.sol

@@ -48,8 +48,8 @@ contract c {
 // storageEmpty -> 0
 // test_long() -> 67
 // gas irOptimized: 89148
-// gas legacy: 103590
-// gas legacyOptimized: 101044
+// gas legacy: 103039
+// gas legacyOptimized: 100493
 // storageEmpty -> 0
 // test_pop() -> 1780731860627700044960722568376592200742329637303199754547598369979433020
 // gas legacy: 61930