diff options
6 files changed, 79 insertions, 36 deletions
diff --git a/libyul/optimiser/DataFlowAnalyzer.cpp b/libyul/optimiser/DataFlowAnalyzer.cpp index 7bff2c89..c8d236dc 100644 --- a/libyul/optimiser/DataFlowAnalyzer.cpp +++ b/libyul/optimiser/DataFlowAnalyzer.cpp @@ -96,7 +96,10 @@ void DataFlowAnalyzer::operator()(FunctionDefinition& _fun) for (auto const& parameter: _fun.parameters) m_variableScopes.back().variables.emplace(parameter.name); for (auto const& var: _fun.returnVariables) + { m_variableScopes.back().variables.emplace(var.name); + handleAssignment({var.name}, nullptr); + } ASTModifier::operator()(_fun); popScope(); diff --git a/libyul/optimiser/SSAValueTracker.cpp b/libyul/optimiser/SSAValueTracker.cpp index a0e44b2b..23eb9ec2 100644 --- a/libyul/optimiser/SSAValueTracker.cpp +++ b/libyul/optimiser/SSAValueTracker.cpp @@ -33,12 +33,18 @@ void SSAValueTracker::operator()(Assignment const& _assignment) m_values.erase(var.name); } +void SSAValueTracker::operator()(FunctionDefinition const& _funDef) +{ + for (auto const& var: _funDef.returnVariables) + setValue(var.name, nullptr); + ASTWalker::operator()(_funDef); +} + void SSAValueTracker::operator()(VariableDeclaration const& _varDecl) { - static Expression const zero{Literal{{}, LiteralKind::Number, YulString{"0"}, {}}}; if (!_varDecl.value) for (auto const& var: _varDecl.variables) - setValue(var.name, &zero); + setValue(var.name, nullptr); else if (_varDecl.variables.size() == 1) setValue(_varDecl.variables.front().name, _varDecl.value.get()); } @@ -50,5 +56,8 @@ void SSAValueTracker::setValue(YulString _name, Expression const* _value) OptimizerException, "Source needs to be disambiguated." ); + static Expression const zero{Literal{{}, LiteralKind::Number, YulString{"0"}, {}}}; + if (!_value) + _value = &zero; m_values[_name] = _value; } diff --git a/libyul/optimiser/SSAValueTracker.h b/libyul/optimiser/SSAValueTracker.h index 0a6cde80..0680485f 100644 --- a/libyul/optimiser/SSAValueTracker.h +++ b/libyul/optimiser/SSAValueTracker.h @@ -41,6 +41,7 @@ class SSAValueTracker: public ASTWalker { public: using ASTWalker::operator(); + void operator()(FunctionDefinition const& _funDef) override; void operator()(VariableDeclaration const& _varDecl) override; void operator()(Assignment const& _assignment) override; diff --git a/test/libyul/yulOptimizerTests/commonSubexpressionEliminator/unassigned_return.yul b/test/libyul/yulOptimizerTests/commonSubexpressionEliminator/unassigned_return.yul new file mode 100644 index 00000000..5283ef9a --- /dev/null +++ b/test/libyul/yulOptimizerTests/commonSubexpressionEliminator/unassigned_return.yul @@ -0,0 +1,23 @@ +{ + function f() -> x { + // can re-use x + let y := 0 + mstore(y, 7) + } + let a + // can re-use a + let b := 0 + sstore(a, b) +} +// ---- +// commonSubexpressionEliminator +// { +// function f() -> x +// { +// let y := x +// mstore(x, 7) +// } +// let a +// let b := a +// sstore(a, a) +// } diff --git a/test/libyul/yulOptimizerTests/expressionSimplifier/return_vars_zero.yul b/test/libyul/yulOptimizerTests/expressionSimplifier/return_vars_zero.yul new file mode 100644 index 00000000..46f9bc40 --- /dev/null +++ b/test/libyul/yulOptimizerTests/expressionSimplifier/return_vars_zero.yul @@ -0,0 +1,14 @@ +// return variables are assumed to be zero initially. +{ + function f() -> c, d { + let y := add(d, add(c, 7)) + } +} +// ---- +// expressionSimplifier +// { +// function f() -> c, d +// { +// let y := 7 +// } +// } diff --git a/test/libyul/yulOptimizerTests/fullSuite/abi_example1.yul b/test/libyul/yulOptimizerTests/fullSuite/abi_example1.yul index ec848015..a3d59ff4 100644 --- a/test/libyul/yulOptimizerTests/fullSuite/abi_example1.yul +++ b/test/libyul/yulOptimizerTests/fullSuite/abi_example1.yul @@ -463,11 +463,12 @@ // let _2 := 0 // let _485 := mload(_2) // let abi_encode_pos := _1 +// let abi_encode_end_67_610 // let abi_encode_length_68 := mload(_485) // mstore(_1, abi_encode_length_68) // abi_encode_pos := 64 // let abi_encode_srcPtr := add(_485, _1) -// let abi_encode_i_69 := _2 +// let abi_encode_i_69 := abi_encode_end_67_610 // for { // } // lt(abi_encode_i_69, abi_encode_length_68) @@ -475,21 +476,21 @@ // abi_encode_i_69 := add(abi_encode_i_69, 1) // } // { -// let _854 := mload(abi_encode_srcPtr) -// let abi_encode_pos_71_961 := abi_encode_pos -// let abi_encode_length_72_962 := 0x3 -// let abi_encode_srcPtr_73_963 := _854 -// let abi_encode_i_74_964 := _2 +// let _857 := mload(abi_encode_srcPtr) +// let abi_encode_pos_71_965 := abi_encode_pos +// let abi_encode_length_72_966 := 0x3 +// let abi_encode_srcPtr_73_967 := _857 +// let abi_encode_i_74_968 := _2 // for { // } -// lt(abi_encode_i_74_964, abi_encode_length_72_962) +// lt(abi_encode_i_74_968, abi_encode_length_72_966) // { -// abi_encode_i_74_964 := add(abi_encode_i_74_964, 1) +// abi_encode_i_74_968 := add(abi_encode_i_74_968, 1) // } // { -// mstore(abi_encode_pos_71_961, and(mload(abi_encode_srcPtr_73_963), 0xFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFF)) -// abi_encode_srcPtr_73_963 := add(abi_encode_srcPtr_73_963, _1) -// abi_encode_pos_71_961 := add(abi_encode_pos_71_961, _1) +// mstore(abi_encode_pos_71_965, and(mload(abi_encode_srcPtr_73_967), 0xFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFF)) +// abi_encode_srcPtr_73_967 := add(abi_encode_srcPtr_73_967, _1) +// abi_encode_pos_71_965 := add(abi_encode_pos_71_965, _1) // } // abi_encode_srcPtr := add(abi_encode_srcPtr, _1) // abi_encode_pos := add(abi_encode_pos, 0x60) @@ -503,8 +504,7 @@ // { // if iszero(slt(add(offset_3, 0x1f), end_4)) // { -// let _33 := 0 -// revert(_33, _33) +// revert(array_5, array_5) // } // let length_6 := calldataload(offset_3) // let array_5_254 := allocateMemory(array_allocation_size_t_array$_t_array$_t_uint256_$2_memory_$dyn_memory_ptr(length_6)) @@ -538,17 +538,16 @@ // { // if iszero(slt(add(offset_11, 0x1f), end_12)) // { -// let _52 := 0 -// revert(_52, _52) +// revert(array_13, array_13) // } // let length_14 := 0x2 -// let array_allo__558 := 0x20 -// let array_allo_size_95_604 := 64 -// let array_13_263 := allocateMemory(array_allo_size_95_604) +// let array_allo__559 := 0x20 +// let array_allo_size_95_605 := 64 +// let array_13_263 := allocateMemory(array_allo_size_95_605) // array_13 := array_13_263 // let dst_15 := array_13_263 // let src_16 := offset_11 -// if gt(add(offset_11, array_allo_size_95_604), end_12) +// if gt(add(offset_11, array_allo_size_95_605), end_12) // { // let _59 := 0 // revert(_59, _59) @@ -562,16 +561,15 @@ // } // { // mstore(dst_15, calldataload(src_16)) -// dst_15 := add(dst_15, array_allo__558) -// src_16 := add(src_16, array_allo__558) +// dst_15 := add(dst_15, array_allo__559) +// src_16 := add(src_16, array_allo__559) // } // } // function abi_decode_t_array$_t_uint256_$dyn_memory_ptr(offset_27, end_28) -> array_29 // { // if iszero(slt(add(offset_27, 0x1f), end_28)) // { -// let _88 := 0 -// revert(_88, _88) +// revert(array_29, array_29) // } // let length_30 := calldataload(offset_27) // let array_29_279 := allocateMemory(array_allocation_size_t_array$_t_uint256_$dyn_memory_ptr(length_30)) @@ -604,11 +602,10 @@ // { // if slt(sub(dataEnd_59, headStart_58), 128) // { -// let _159 := 0 -// revert(_159, _159) +// revert(value2, value2) // } // { -// value0_60 := calldataload(headStart_58) +// value0_60 := calldataload(add(headStart_58, value2)) // } // { // value1_61 := calldataload(add(headStart_58, 32)) @@ -617,8 +614,7 @@ // let offset_64 := calldataload(add(headStart_58, 64)) // if gt(offset_64, 0xffffffffffffffff) // { -// let _167 := 0 -// revert(_167, _167) +// revert(value2, value2) // } // value2 := abi_decode_t_array$_t_uint256_$dyn_memory_ptr(add(headStart_58, offset_64), dataEnd_59) // } @@ -626,8 +622,7 @@ // let offset_65 := calldataload(add(headStart_58, 96)) // if gt(offset_65, 0xffffffffffffffff) // { -// let _174 := 0 -// revert(_174, _174) +// revert(value3, value3) // } // value3 := abi_decode_t_array$_t_array$_t_uint256_$2_memory_$dyn_memory_ptr(add(headStart_58, offset_65), dataEnd_59) // } @@ -649,8 +644,7 @@ // { // if gt(length_92, 0xffffffffffffffff) // { -// let _215 := 0 -// revert(_215, _215) +// revert(size_93, size_93) // } // let _217 := 0x20 // size_93 := add(mul(length_92, _217), _217) @@ -659,8 +653,7 @@ // { // if gt(length_98, 0xffffffffffffffff) // { -// let _232 := 0 -// revert(_232, _232) +// revert(size_99, size_99) // } // let _234 := 0x20 // size_99 := add(mul(length_98, _234), _234) |