aboutsummaryrefslogtreecommitdiffstats
diff options
context:
space:
mode:
-rw-r--r--libdevcore/CommonData.h53
-rw-r--r--libyul/CMakeLists.txt2
-rw-r--r--libyul/optimiser/Metrics.cpp12
-rw-r--r--libyul/optimiser/Metrics.h14
-rw-r--r--libyul/optimiser/SSAReverser.cpp114
-rw-r--r--libyul/optimiser/SSAReverser.h74
-rw-r--r--libyul/optimiser/Suite.cpp13
-rw-r--r--test/libyul/YulOptimizerTest.cpp18
-rw-r--r--test/libyul/yulOptimizerTests/fullSuite/abi2.yul38
-rw-r--r--test/libyul/yulOptimizerTests/fullSuite/abi_example1.yul92
-rw-r--r--test/libyul/yulOptimizerTests/fullSuite/aztec.yul66
-rw-r--r--test/libyul/yulOptimizerTests/fullSuite/medium.yul6
-rw-r--r--test/libyul/yulOptimizerTests/fullSuite/ssaReverse.yul62
-rw-r--r--test/libyul/yulOptimizerTests/fullSuite/ssaReverseComplex.yul23
-rw-r--r--test/libyul/yulOptimizerTests/ssaAndBack/for_loop.yul36
-rw-r--r--test/libyul/yulOptimizerTests/ssaAndBack/multi_assign.yul18
-rw-r--r--test/libyul/yulOptimizerTests/ssaAndBack/multi_assign_if.yul22
-rw-r--r--test/libyul/yulOptimizerTests/ssaAndBack/multi_assign_multi_var_if.yul25
-rw-r--r--test/libyul/yulOptimizerTests/ssaAndBack/multi_assign_multi_var_switch.yul38
-rw-r--r--test/libyul/yulOptimizerTests/ssaAndBack/multi_assign_switch.yul32
-rw-r--r--test/libyul/yulOptimizerTests/ssaAndBack/simple.yul12
-rw-r--r--test/libyul/yulOptimizerTests/ssaAndBack/single_assign_if.yul18
-rw-r--r--test/libyul/yulOptimizerTests/ssaAndBack/single_assign_switch.yul24
-rw-r--r--test/libyul/yulOptimizerTests/ssaAndBack/ssaReverse.yul45
-rw-r--r--test/libyul/yulOptimizerTests/ssaAndBack/two_vars.yul20
-rw-r--r--test/libyul/yulOptimizerTests/ssaReverser/abi_example.yul44
-rw-r--r--test/libyul/yulOptimizerTests/ssaReverser/simple.yul14
-rw-r--r--test/tools/yulopti.cpp6
28 files changed, 832 insertions, 109 deletions
diff --git a/libdevcore/CommonData.h b/libdevcore/CommonData.h
index 1d668f26..98331936 100644
--- a/libdevcore/CommonData.h
+++ b/libdevcore/CommonData.h
@@ -263,6 +263,59 @@ void iterateReplacing(std::vector<T>& _vector, const F& _f)
_vector = std::move(modifiedVector);
}
+
+namespace detail
+{
+template <typename T, typename F, std::size_t... I>
+void iterateReplacingWindow(std::vector<T>& _vector, F const& _f, std::index_sequence<I...>)
+{
+ // Concept: _f must be Callable, must accept sizeof...(I) parameters of type T&, must return optional<vector<T>>
+ bool useModified = false;
+ std::vector<T> modifiedVector;
+ size_t i = 0;
+ for (; i + sizeof...(I) <= _vector.size(); ++i)
+ {
+ if (boost::optional<std::vector<T>> r = _f(_vector[i + I]...))
+ {
+ if (!useModified)
+ {
+ std::move(_vector.begin(), _vector.begin() + i, back_inserter(modifiedVector));
+ useModified = true;
+ }
+ modifiedVector += std::move(*r);
+ i += sizeof...(I) - 1;
+ }
+ else if (useModified)
+ modifiedVector.emplace_back(std::move(_vector[i]));
+ }
+ if (useModified)
+ {
+ for (; i < _vector.size(); ++i)
+ modifiedVector.emplace_back(std::move(_vector[i]));
+ _vector = std::move(modifiedVector);
+ }
+}
+
+}
+
+/// Function that iterates over the vector @param _vector,
+/// calling the function @param _f on sequences of @tparam N of its
+/// elements. If @param _f returns a vector, these elements are replaced by
+/// the returned vector and the iteration continues with the next @tparam N elements.
+/// If the function does not return a vector, the iteration continues with an overlapping
+/// sequence of @tparam N elements that starts with the second element of the previous
+/// iteration.
+/// During the iteration, the original vector is only valid
+/// on the current element and after that. The actual replacement takes
+/// place at the end, but already visited elements might be invalidated.
+/// If nothing is replaced, no copy is performed.
+template <std::size_t N, typename T, typename F>
+void iterateReplacingWindow(std::vector<T>& _vector, F const& _f)
+{
+ // Concept: _f must be Callable, must accept N parameters of type T&, must return optional<vector<T>>
+ detail::iterateReplacingWindow(_vector, _f, std::make_index_sequence<N>{});
+}
+
/// @returns true iff @a _str passess the hex address checksum test.
/// @param _strict if false, hex strings with only uppercase or only lowercase letters
/// are considered valid.
diff --git a/libyul/CMakeLists.txt b/libyul/CMakeLists.txt
index 44af2fc3..259f43f8 100644
--- a/libyul/CMakeLists.txt
+++ b/libyul/CMakeLists.txt
@@ -80,6 +80,8 @@ add_library(yul
optimiser/RedundantAssignEliminator.h
optimiser/Rematerialiser.cpp
optimiser/Rematerialiser.h
+ optimiser/SSAReverser.cpp
+ optimiser/SSAReverser.h
optimiser/SSATransform.cpp
optimiser/SSATransform.h
optimiser/SSAValueTracker.cpp
diff --git a/libyul/optimiser/Metrics.cpp b/libyul/optimiser/Metrics.cpp
index df919682..e13940aa 100644
--- a/libyul/optimiser/Metrics.cpp
+++ b/libyul/optimiser/Metrics.cpp
@@ -134,3 +134,15 @@ void CodeCost::visit(Expression const& _expression)
++m_cost;
ASTWalker::visit(_expression);
}
+
+void AssignmentCounter::operator()(Assignment const& _assignment)
+{
+ for (auto const& variable: _assignment.variableNames)
+ ++m_assignmentCounters[variable.name];
+}
+
+size_t AssignmentCounter::assignmentCount(YulString _name) const
+{
+ auto it = m_assignmentCounters.find(_name);
+ return (it == m_assignmentCounters.end()) ? 0 : it->second;
+}
diff --git a/libyul/optimiser/Metrics.h b/libyul/optimiser/Metrics.h
index 03e1b62a..5364646e 100644
--- a/libyul/optimiser/Metrics.h
+++ b/libyul/optimiser/Metrics.h
@@ -77,4 +77,18 @@ private:
size_t m_cost = 0;
};
+/**
+ * Counts the number of assignments to every variable.
+ * Only works after running the Disambiguator.
+ */
+class AssignmentCounter: public ASTWalker
+{
+public:
+ using ASTWalker::operator();
+ void operator()(Assignment const& _assignment) override;
+ std::size_t assignmentCount(YulString _name) const;
+private:
+ std::map<YulString, size_t> m_assignmentCounters;
+};
+
}
diff --git a/libyul/optimiser/SSAReverser.cpp b/libyul/optimiser/SSAReverser.cpp
new file mode 100644
index 00000000..6548ebb5
--- /dev/null
+++ b/libyul/optimiser/SSAReverser.cpp
@@ -0,0 +1,114 @@
+/*
+ This file is part of solidity.
+
+ solidity 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.
+
+ solidity 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 solidity. If not, see <http://www.gnu.org/licenses/>.
+*/
+#include <libyul/optimiser/SSAReverser.h>
+#include <libyul/optimiser/Metrics.h>
+#include <libyul/AsmData.h>
+#include <libdevcore/CommonData.h>
+
+using namespace std;
+using namespace dev;
+using namespace yul;
+
+void SSAReverser::run(Block& _block)
+{
+ AssignmentCounter assignmentCounter;
+ assignmentCounter(_block);
+ SSAReverser{assignmentCounter}(_block);
+}
+
+void SSAReverser::operator()(Block& _block)
+{
+ walkVector(_block.statements);
+ iterateReplacingWindow<2>(
+ _block.statements,
+ [&](Statement& _stmt1, Statement& _stmt2) -> boost::optional<vector<Statement>>
+ {
+ auto* varDecl = boost::get<VariableDeclaration>(&_stmt1);
+
+ if (!varDecl || varDecl->variables.size() != 1 || !varDecl->value)
+ return {};
+
+ // Replaces
+ // let a_1 := E
+ // a := a_1
+ // with
+ // a := E
+ // let a_1 := a
+ if (auto* assignment = boost::get<Assignment>(&_stmt2))
+ {
+ auto* identifier = boost::get<Identifier>(assignment->value.get());
+ if (
+ assignment->variableNames.size() == 1 &&
+ identifier &&
+ identifier->name == varDecl->variables.front().name
+ )
+ {
+ vector<Statement> result;
+ result.emplace_back(Assignment{
+ std::move(assignment->location),
+ assignment->variableNames,
+ std::move(varDecl->value)
+ });
+ result.emplace_back(VariableDeclaration{
+ std::move(varDecl->location),
+ std::move(varDecl->variables),
+ std::make_unique<Expression>(std::move(assignment->variableNames.front()))
+ });
+ return { std::move(result) };
+ }
+ }
+ // Replaces
+ // let a_1 := E
+ // let a := a_1
+ // with
+ // let a := E
+ // let a_1 := a
+ else if (auto* varDecl2 = boost::get<VariableDeclaration>(&_stmt2))
+ {
+ auto* identifier = boost::get<Identifier>(varDecl2->value.get());
+ if (
+ varDecl2->variables.size() == 1 &&
+ identifier &&
+ identifier->name == varDecl->variables.front().name && (
+ m_assignmentCounter.assignmentCount(varDecl2->variables.front().name) >
+ m_assignmentCounter.assignmentCount(varDecl->variables.front().name)
+ )
+ )
+ {
+ vector<Statement> result;
+ auto varIdentifier2 = std::make_unique<Expression>(Identifier{
+ varDecl2->variables.front().location,
+ varDecl2->variables.front().name
+ });
+ result.emplace_back(VariableDeclaration{
+ std::move(varDecl2->location),
+ std::move(varDecl2->variables),
+ std::move(varDecl->value)
+ });
+ result.emplace_back(VariableDeclaration{
+ std::move(varDecl->location),
+ std::move(varDecl->variables),
+ std::move(varIdentifier2)
+ });
+ return { std::move(result) };
+ }
+ }
+
+ return {};
+ }
+ );
+}
diff --git a/libyul/optimiser/SSAReverser.h b/libyul/optimiser/SSAReverser.h
new file mode 100644
index 00000000..67abeb56
--- /dev/null
+++ b/libyul/optimiser/SSAReverser.h
@@ -0,0 +1,74 @@
+/*
+ This file is part of solidity.
+
+ solidity 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.
+
+ solidity 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 solidity. If not, see <http://www.gnu.org/licenses/>.
+*/
+#pragma once
+
+#include <libyul/optimiser/ASTWalker.h>
+
+namespace yul
+{
+
+class AssignmentCounter;
+
+/**
+ * Reverses the SSA transformation.
+ *
+ * In particular, the SSA transform will rewrite
+ *
+ * a := E
+ *
+ * to
+ *
+ * let a_1 := E
+ * a := a_1
+ *
+ * To undo this kind of transformation, the SSAReverser changes this back to
+ *
+ * a := E
+ * let a_1 := a
+ *
+ * Secondly, the SSA transform will rewrite
+ *
+ * let a := E
+ * to
+ *
+ * let a_1 := E
+ * let a := a_1
+ *
+ * To undo this kind of transformation, the SSAReverser changes this back to
+ *
+ * let a := E
+ * let a_1 := a
+ *
+ * After that the CSE can replace references of a_1 by references to a,
+ * after which the unused pruner can remove the declaration of a_1.
+ *
+ * Prerequisites: Disambiguator
+ *
+ */
+class SSAReverser: public ASTModifier
+{
+public:
+ using ASTModifier::operator();
+ void operator()(Block& _block) override;
+
+ static void run(Block& _block);
+private:
+ SSAReverser(AssignmentCounter const& _assignmentCounter): m_assignmentCounter(_assignmentCounter) {}
+ AssignmentCounter const& m_assignmentCounter;
+};
+
+}
diff --git a/libyul/optimiser/Suite.cpp b/libyul/optimiser/Suite.cpp
index 38c0bf49..8cf6e104 100644
--- a/libyul/optimiser/Suite.cpp
+++ b/libyul/optimiser/Suite.cpp
@@ -35,6 +35,7 @@
#include <libyul/optimiser/UnusedPruner.h>
#include <libyul/optimiser/ExpressionSimplifier.h>
#include <libyul/optimiser/CommonSubexpressionEliminator.h>
+#include <libyul/optimiser/SSAReverser.h>
#include <libyul/optimiser/SSATransform.h>
#include <libyul/optimiser/StructuralSimplifier.h>
#include <libyul/optimiser/RedundantAssignEliminator.h>
@@ -88,9 +89,10 @@ void OptimiserSuite::run(
UnusedPruner::runUntilStabilised(_dialect, ast, reservedIdentifiers);
CommonSubexpressionEliminator{_dialect}(ast);
UnusedPruner::runUntilStabilised(_dialect, ast, reservedIdentifiers);
- SSATransform::run(ast, dispenser);
- RedundantAssignEliminator::run(_dialect, ast);
- RedundantAssignEliminator::run(_dialect, ast);
+
+ SSAReverser::run(ast);
+ CommonSubexpressionEliminator{_dialect}(ast);
+ UnusedPruner::runUntilStabilised(_dialect, ast, reservedIdentifiers);
ExpressionJoiner::run(ast);
ExpressionJoiner::run(ast);
@@ -127,6 +129,11 @@ void OptimiserSuite::run(
UnusedPruner::runUntilStabilised(_dialect, ast);
ExpressionJoiner::run(ast);
UnusedPruner::runUntilStabilised(_dialect, ast);
+
+ SSAReverser::run(ast);
+ CommonSubexpressionEliminator{_dialect}(ast);
+ UnusedPruner::runUntilStabilised(_dialect, ast, reservedIdentifiers);
+
ExpressionJoiner::run(ast);
Rematerialiser::run(_dialect, ast);
UnusedPruner::runUntilStabilised(_dialect, ast);
diff --git a/test/libyul/YulOptimizerTest.cpp b/test/libyul/YulOptimizerTest.cpp
index 59cde4fe..306721a0 100644
--- a/test/libyul/YulOptimizerTest.cpp
+++ b/test/libyul/YulOptimizerTest.cpp
@@ -38,6 +38,7 @@
#include <libyul/optimiser/ExpressionSimplifier.h>
#include <libyul/optimiser/UnusedPruner.h>
#include <libyul/optimiser/ExpressionJoiner.h>
+#include <libyul/optimiser/SSAReverser.h>
#include <libyul/optimiser/SSATransform.h>
#include <libyul/optimiser/RedundantAssignEliminator.h>
#include <libyul/optimiser/StructuralSimplifier.h>
@@ -223,6 +224,23 @@ bool YulOptimizerTest::run(ostream& _stream, string const& _linePrefix, bool con
disambiguate();
EquivalentFunctionCombiner::run(*m_ast);
}
+ else if (m_optimizerStep == "ssaReverser")
+ {
+ disambiguate();
+ SSAReverser::run(*m_ast);
+ }
+ else if (m_optimizerStep == "ssaAndBack")
+ {
+ disambiguate();
+ // apply SSA
+ NameDispenser nameDispenser{*m_dialect, *m_ast};
+ SSATransform::run(*m_ast, nameDispenser);
+ RedundantAssignEliminator::run(*m_dialect, *m_ast);
+ // reverse SSA
+ SSAReverser::run(*m_ast);
+ CommonSubexpressionEliminator{*m_dialect}(*m_ast);
+ UnusedPruner::runUntilStabilised(*m_dialect, *m_ast);
+ }
else if (m_optimizerStep == "fullSuite")
OptimiserSuite::run(*m_dialect, *m_ast, *m_analysisInfo);
else
diff --git a/test/libyul/yulOptimizerTests/fullSuite/abi2.yul b/test/libyul/yulOptimizerTests/fullSuite/abi2.yul
index 887399b6..41a52c67 100644
--- a/test/libyul/yulOptimizerTests/fullSuite/abi2.yul
+++ b/test/libyul/yulOptimizerTests/fullSuite/abi2.yul
@@ -1073,12 +1073,12 @@
// fullSuite
// {
// let _2 := mload(1)
-// let _172 := mload(0)
-// if slt(sub(_2, _172), 64)
+// let _153 := mload(0)
+// if slt(sub(_2, _153), 64)
// {
// revert(0, 0)
// }
-// sstore(0, and(calldataload(_172), 0xFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFF))
+// sstore(0, and(calldataload(_153), 0xFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFF))
// let x0, x1, x2, x3, x4 := abi_decode_tuple_t_addresst_uint256t_bytes_calldata_ptrt_enum$_Operation_$1949(mload(7), mload(8))
// sstore(x1, x0)
// sstore(x3, x2)
@@ -1093,40 +1093,40 @@
// value0_57 := and(calldataload(add(headStart_55, value4)), 0xFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFF)
// value1_58 := calldataload(add(headStart_55, 32))
// let offset_62 := calldataload(add(headStart_55, 64))
-// let _220 := 0xffffffffffffffff
-// if gt(offset_62, _220)
+// let _201 := 0xffffffffffffffff
+// if gt(offset_62, _201)
// {
// revert(value4, value4)
// }
-// let _222 := add(headStart_55, offset_62)
-// if iszero(slt(add(_222, 0x1f), dataEnd_56))
+// let _203 := add(headStart_55, offset_62)
+// if iszero(slt(add(_203, 0x1f), dataEnd_56))
// {
// revert(value4, value4)
// }
-// let abi_decode_length_15_116 := calldataload(_222)
-// if gt(abi_decode_length_15_116, _220)
+// let abi_decode_length_15_246 := calldataload(_203)
+// if gt(abi_decode_length_15_246, _201)
// {
// revert(value4, value4)
// }
-// if gt(add(add(_222, abi_decode_length_15_116), 32), dataEnd_56)
+// if gt(add(add(_203, abi_decode_length_15_246), 32), dataEnd_56)
// {
// revert(value4, value4)
// }
-// value2_59 := add(_222, 32)
-// value3 := abi_decode_length_15_116
-// let _225 := calldataload(add(headStart_55, 96))
-// if iszero(lt(_225, 3))
+// value2_59 := add(_203, 32)
+// value3 := abi_decode_length_15_246
+// let _206 := calldataload(add(headStart_55, 96))
+// if iszero(lt(_206, 3))
// {
// revert(value4, value4)
// }
-// value4 := _225
+// value4 := _206
// }
// function abi_encode_tuple_t_bytes32_t_address_t_uint256_t_bytes32_t_enum$_Operation_$1949_t_uint256_t_uint256_t_uint256_t_address_t_address_t_uint256__to_t_bytes32_t_address_t_uint256_t_bytes32_t_uint8_t_uint256_t_uint256_t_uint256_t_address_t_address_t_uint256_(headStart_252, value10_253, value9_254, value8_255, value7_256, value6_257, value5_258, value4_259, value3_260, value2_261, value1_262, value0_263) -> tail_264
// {
// tail_264 := add(headStart_252, 352)
// mstore(headStart_252, value0_263)
-// let _439 := 0xFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFF
-// mstore(add(headStart_252, 32), and(value1_262, _439))
+// let _413 := 0xFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFF
+// mstore(add(headStart_252, 32), and(value1_262, _413))
// mstore(add(headStart_252, 64), value2_261)
// mstore(add(headStart_252, 96), value3_260)
// if iszero(lt(value4_259, 3))
@@ -1137,8 +1137,8 @@
// mstore(add(headStart_252, 160), value5_258)
// mstore(add(headStart_252, 192), value6_257)
// mstore(add(headStart_252, 224), value7_256)
-// mstore(add(headStart_252, 256), and(value8_255, _439))
-// mstore(add(headStart_252, 288), and(value9_254, _439))
+// mstore(add(headStart_252, 256), and(value8_255, _413))
+// mstore(add(headStart_252, 288), and(value9_254, _413))
// mstore(add(headStart_252, 320), value10_253)
// }
// }
diff --git a/test/libyul/yulOptimizerTests/fullSuite/abi_example1.yul b/test/libyul/yulOptimizerTests/fullSuite/abi_example1.yul
index a8cac6c6..d38025ae 100644
--- a/test/libyul/yulOptimizerTests/fullSuite/abi_example1.yul
+++ b/test/libyul/yulOptimizerTests/fullSuite/abi_example1.yul
@@ -460,12 +460,12 @@
// {
// let _1 := 0x20
// let _2 := 0
-// let _268 := mload(_2)
+// let _218 := mload(_2)
// let abi_encode_pos := _1
-// let abi_encode_length_68 := mload(_268)
+// let abi_encode_length_68 := mload(_218)
// mstore(_1, abi_encode_length_68)
// abi_encode_pos := 64
-// let abi_encode_srcPtr := add(_268, _1)
+// let abi_encode_srcPtr := add(_218, _1)
// let abi_encode_i_69 := _2
// for {
// }
@@ -474,66 +474,64 @@
// abi_encode_i_69 := add(abi_encode_i_69, 1)
// }
// {
-// let _668 := mload(abi_encode_srcPtr)
-// let abi_encode_pos_71_760 := abi_encode_pos
-// let abi_encode_srcPtr_73_762 := _668
-// let abi_encode_i_74_763 := _2
+// let _580 := mload(abi_encode_srcPtr)
+// let abi_encode_pos_71_672 := abi_encode_pos
+// let abi_encode_srcPtr_73_674 := _580
+// let abi_encode_i_74_675 := _2
// for {
// }
-// lt(abi_encode_i_74_763, 0x3)
+// lt(abi_encode_i_74_675, 0x3)
// {
-// abi_encode_i_74_763 := add(abi_encode_i_74_763, 1)
+// abi_encode_i_74_675 := add(abi_encode_i_74_675, 1)
// }
// {
-// mstore(abi_encode_pos_71_760, and(mload(abi_encode_srcPtr_73_762), 0xFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFF))
-// abi_encode_srcPtr_73_762 := add(abi_encode_srcPtr_73_762, _1)
-// abi_encode_pos_71_760 := add(abi_encode_pos_71_760, _1)
+// mstore(abi_encode_pos_71_672, and(mload(abi_encode_srcPtr_73_674), 0xFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFF))
+// abi_encode_srcPtr_73_674 := add(abi_encode_srcPtr_73_674, _1)
+// abi_encode_pos_71_672 := add(abi_encode_pos_71_672, _1)
// }
// abi_encode_srcPtr := add(abi_encode_srcPtr, _1)
// abi_encode_pos := add(abi_encode_pos, 0x60)
// }
-// let _270 := mload(64)
-// let _271 := mload(_1)
-// if slt(sub(_270, _271), 128)
+// let _220 := mload(64)
+// let _221 := mload(_1)
+// if slt(sub(_220, _221), 128)
// {
// revert(_2, _2)
// }
-// let abi_decode_offset_64 := calldataload(add(_271, 64))
+// let abi_decode_offset_64 := calldataload(add(_221, 64))
// let abi_decode__74 := 0xffffffffffffffff
// if gt(abi_decode_offset_64, abi_decode__74)
// {
// revert(_2, _2)
// }
-// let abi_decode_value2_367 := abi_decode_t_array$_t_uint256_$dyn_memory_ptr(add(_271, abi_decode_offset_64), _270)
-// let abi_decode_offset_65 := calldataload(add(_271, 96))
+// let abi_decode_value2_317 := abi_decode_t_array$_t_uint256_$dyn_memory_ptr(add(_221, abi_decode_offset_64), _220)
+// let abi_decode_offset_65 := calldataload(add(_221, 96))
// if gt(abi_decode_offset_65, abi_decode__74)
// {
// revert(_2, _2)
// }
-// let abi_decode_value3_368 := abi_decode_t_array$_t_array$_t_uint256_$2_memory_$dyn_memory_ptr(add(_271, abi_decode_offset_65), _270)
-// sstore(calldataload(_271), calldataload(add(_271, _1)))
-// sstore(abi_decode_value2_367, abi_decode_value3_368)
+// let abi_decode_value3_318 := abi_decode_t_array$_t_array$_t_uint256_$2_memory_$dyn_memory_ptr(add(_221, abi_decode_offset_65), _220)
+// sstore(calldataload(_221), calldataload(add(_221, _1)))
+// sstore(abi_decode_value2_317, abi_decode_value3_318)
// sstore(_2, abi_encode_pos)
// function abi_decode_t_array$_t_array$_t_uint256_$2_memory_$dyn_memory_ptr(offset_3, end_4) -> array_5
// {
// if iszero(slt(add(offset_3, 0x1f), end_4))
// {
-// revert(0, 0)
+// revert(array_5, array_5)
// }
// let length_6 := calldataload(offset_3)
-// let array_5_115 := allocateMemory(array_allocation_size_t_array$_t_address_$dyn_memory(length_6))
-// array_5 := array_5_115
-// let dst_7 := array_5_115
-// mstore(array_5_115, length_6)
+// array_5 := allocateMemory(array_allocation_size_t_array$_t_address_$dyn_memory(length_6))
+// let dst_7 := array_5
+// mstore(array_5, length_6)
// let _16 := 0x20
-// dst_7 := add(array_5_115, _16)
+// dst_7 := add(array_5, _16)
// let src_8 := add(offset_3, _16)
// if gt(add(add(offset_3, mul(length_6, 0x40)), _16), end_4)
// {
// revert(0, 0)
// }
-// let i_9_346 := 0
-// let i_9 := i_9_346
+// let i_9 := 0
// for {
// }
// lt(i_9, length_6)
@@ -543,17 +541,17 @@
// {
// if iszero(slt(add(src_8, 0x1f), end_4))
// {
-// revert(i_9_346, i_9_346)
+// revert(0, 0)
// }
-// let abi_decode_array_13_124 := allocateMemory(array_allocation_size_t_array$_t_uint256_$2_memory(0x2))
-// let abi_decode_dst_15 := abi_decode_array_13_124
+// let abi_decode_dst_15 := allocateMemory(array_allocation_size_t_array$_t_uint256_$2_memory(0x2))
+// let abi_decode_dst_15_1155 := abi_decode_dst_15
// let abi_decode_src_16 := src_8
-// let abi_decode__289 := add(src_8, 0x40)
-// if gt(abi_decode__289, end_4)
+// let abi_decode__239 := add(src_8, 0x40)
+// if gt(abi_decode__239, end_4)
// {
-// revert(i_9_346, i_9_346)
+// revert(0, 0)
// }
-// let abi_decode_i_17 := i_9_346
+// let abi_decode_i_17 := 0
// for {
// }
// lt(abi_decode_i_17, 0x2)
@@ -565,24 +563,23 @@
// abi_decode_dst_15 := add(abi_decode_dst_15, _16)
// abi_decode_src_16 := add(abi_decode_src_16, _16)
// }
-// mstore(dst_7, abi_decode_array_13_124)
+// mstore(dst_7, abi_decode_dst_15_1155)
// dst_7 := add(dst_7, _16)
-// src_8 := abi_decode__289
+// src_8 := abi_decode__239
// }
// }
// function abi_decode_t_array$_t_uint256_$dyn_memory_ptr(offset_27, end_28) -> array_29
// {
// if iszero(slt(add(offset_27, 0x1f), end_28))
// {
-// revert(0, 0)
+// revert(array_29, array_29)
// }
// let length_30 := calldataload(offset_27)
-// let array_29_131 := allocateMemory(array_allocation_size_t_array$_t_address_$dyn_memory(length_30))
-// array_29 := array_29_131
-// let dst_31 := array_29_131
-// mstore(array_29_131, length_30)
+// array_29 := allocateMemory(array_allocation_size_t_array$_t_address_$dyn_memory(length_30))
+// let dst_31 := array_29
+// mstore(array_29, length_30)
// let _52 := 0x20
-// dst_31 := add(array_29_131, _52)
+// dst_31 := add(array_29, _52)
// let src_32 := add(offset_27, _52)
// if gt(add(add(offset_27, mul(length_30, _52)), _52), end_28)
// {
@@ -603,10 +600,9 @@
// }
// function allocateMemory(size) -> memPtr
// {
-// let memPtr_157 := mload(64)
-// memPtr := memPtr_157
-// let newFreePtr := add(memPtr_157, size)
-// if or(gt(newFreePtr, 0xffffffffffffffff), lt(newFreePtr, memPtr_157))
+// memPtr := mload(64)
+// let newFreePtr := add(memPtr, size)
+// if or(gt(newFreePtr, 0xffffffffffffffff), lt(newFreePtr, memPtr))
// {
// revert(0, 0)
// }
diff --git a/test/libyul/yulOptimizerTests/fullSuite/aztec.yul b/test/libyul/yulOptimizerTests/fullSuite/aztec.yul
index fc09b5d9..868c6b01 100644
--- a/test/libyul/yulOptimizerTests/fullSuite/aztec.yul
+++ b/test/libyul/yulOptimizerTests/fullSuite/aztec.yul
@@ -245,17 +245,16 @@
// mstore(0x00, 404)
// revert(0x00, 0x20)
// }
-// let validateJo_kn_287 := calldataload(add(calldatasize(), 0xffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffff40))
-// let validateJo_kn := validateJo_kn_287
+// let validateJo_kn := calldataload(add(calldatasize(), 0xffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffff40))
// let validateJo__24 := 0x2a0
// mstore(validateJo__24, caller())
-// mstore(0x2c0, validateJo_kn_287)
+// mstore(0x2c0, validateJo_kn)
// mstore(0x2e0, validateJo_m)
-// validateJo_kn := mulmod(sub(validateJo_gen_order, validateJo_kn_287), validateJo_challenge, validateJo_gen_order)
+// validateJo_kn := mulmod(sub(validateJo_gen_order, validateJo_kn), validateJo_challenge, validateJo_gen_order)
// hashCommitments(validateJo_notes, validateJo_n)
// let validateJo_b := add(0x300, mul(validateJo_n, validateJo__6))
-// let validateJo_i_290 := 0
-// let validateJo_i := validateJo_i_290
+// let validateJo_i := 0
+// let validateJo_i_1306 := validateJo_i
// for {
// }
// lt(validateJo_i, validateJo_n)
@@ -264,11 +263,10 @@
// }
// {
// let validateJo__34 := 0x20
-// let validateJo__373 := add(validateJo__10, mul(validateJo_i, 0xc0))
-// let validateJo_noteIndex := add(validateJo__373, 0x24)
-// let validateJo_k := validateJo_i_290
-// let validateJo_a_292 := calldataload(add(validateJo__373, 0x44))
-// let validateJo_a := validateJo_a_292
+// let validateJo__351 := add(validateJo__10, mul(validateJo_i, 0xc0))
+// let validateJo_noteIndex := add(validateJo__351, 0x24)
+// let validateJo_k := validateJo_i_1306
+// let validateJo_a := calldataload(add(validateJo__351, 0x44))
// let validateJo_c := validateJo_challenge
// let validateJo__39 := add(validateJo_i, 0x01)
// switch eq(validateJo__39, validateJo_n)
@@ -282,36 +280,34 @@
// case 0 {
// validateJo_k := calldataload(validateJo_noteIndex)
// }
-// validateCommitment(validateJo_noteIndex, validateJo_k, validateJo_a_292)
+// validateCommitment(validateJo_noteIndex, validateJo_k, validateJo_a)
// switch gt(validateJo__39, validateJo_m)
// case 1 {
// validateJo_kn := addmod(validateJo_kn, sub(validateJo_gen_order, validateJo_k), validateJo_gen_order)
-// let validateJo_x := mod(mload(validateJo_i_290), validateJo_gen_order)
+// let validateJo_x := mod(mload(validateJo_i_1306), validateJo_gen_order)
// validateJo_k := mulmod(validateJo_k, validateJo_x, validateJo_gen_order)
-// validateJo_a := mulmod(validateJo_a_292, validateJo_x, validateJo_gen_order)
+// validateJo_a := mulmod(validateJo_a, validateJo_x, validateJo_gen_order)
// validateJo_c := mulmod(validateJo_challenge, validateJo_x, validateJo_gen_order)
-// mstore(validateJo_i_290, keccak256(validateJo_i_290, validateJo__34))
+// mstore(validateJo_i_1306, keccak256(validateJo_i_1306, validateJo__34))
// }
// case 0 {
// validateJo_kn := addmod(validateJo_kn, validateJo_k, validateJo_gen_order)
// }
// let validateJo__52 := 0x40
-// calldatacopy(0xe0, add(validateJo__373, 164), validateJo__52)
-// calldatacopy(validateJo__34, add(validateJo__373, 100), validateJo__52)
+// calldatacopy(0xe0, add(validateJo__351, 164), validateJo__52)
+// calldatacopy(validateJo__34, add(validateJo__351, 100), validateJo__52)
// let validateJo__61 := 0x120
// mstore(validateJo__61, sub(validateJo_gen_order, validateJo_c))
// let validateJo__62 := 0x60
// mstore(validateJo__62, validateJo_k)
// mstore(0xc0, validateJo_a)
// let validateJo__65 := 0x1a0
-// let validateJo_result_302 := call(gas(), 7, validateJo_i_290, 0xe0, validateJo__62, validateJo__65, validateJo__52)
-// let validateJo_result := validateJo_result_302
-// let validateJo_result_303 := and(validateJo_result_302, call(gas(), 7, validateJo_i_290, validateJo__34, validateJo__62, validateJo__61, validateJo__52))
+// let validateJo_result := call(gas(), 7, validateJo_i_1306, 0xe0, validateJo__62, validateJo__65, validateJo__52)
+// let validateJo_result_303 := and(validateJo_result, call(gas(), 7, validateJo_i_1306, validateJo__34, validateJo__62, validateJo__61, validateJo__52))
// let validateJo__80 := 0x160
-// let validateJo_result_304 := and(validateJo_result_303, call(gas(), 7, validateJo_i_290, validateJo__6, validateJo__62, validateJo__80, validateJo__52))
-// let validateJo_result_305 := and(validateJo_result_304, call(gas(), 6, validateJo_i_290, validateJo__61, validateJo__6, validateJo__80, validateJo__52))
-// let validateJo_result_306 := and(validateJo_result_305, call(gas(), 6, validateJo_i_290, validateJo__80, validateJo__6, validateJo_b, validateJo__52))
-// validateJo_result := validateJo_result_306
+// let validateJo_result_304 := and(validateJo_result_303, call(gas(), 7, validateJo_i_1306, validateJo__6, validateJo__62, validateJo__80, validateJo__52))
+// let validateJo_result_305 := and(validateJo_result_304, call(gas(), 6, validateJo_i_1306, validateJo__61, validateJo__6, validateJo__80, validateJo__52))
+// validateJo_result := and(validateJo_result_305, call(gas(), 6, validateJo_i_1306, validateJo__80, validateJo__6, validateJo_b, validateJo__52))
// if eq(validateJo_i, validateJo_m)
// {
// mstore(0x260, mload(validateJo__34))
@@ -323,14 +319,14 @@
// {
// mstore(validateJo__62, validateJo_c)
// let validateJo__120 := 0x220
-// let validateJo_result_307 := and(validateJo_result_306, call(gas(), 7, validateJo_i_290, validateJo__34, validateJo__62, validateJo__120, validateJo__52))
-// let validateJo_result_308 := and(validateJo_result_307, call(gas(), 6, validateJo_i_290, validateJo__120, validateJo__6, 0x260, validateJo__52))
-// validateJo_result := and(validateJo_result_308, call(gas(), 6, validateJo_i_290, validateJo__65, validateJo__6, 0x1e0, validateJo__52))
+// let validateJo_result_307 := and(validateJo_result, call(gas(), 7, validateJo_i_1306, validateJo__34, validateJo__62, validateJo__120, validateJo__52))
+// let validateJo_result_308 := and(validateJo_result_307, call(gas(), 6, validateJo_i_1306, validateJo__120, validateJo__6, 0x260, validateJo__52))
+// validateJo_result := and(validateJo_result_308, call(gas(), 6, validateJo_i_1306, validateJo__65, validateJo__6, 0x1e0, validateJo__52))
// }
// if iszero(validateJo_result)
// {
-// mstore(validateJo_i_290, 400)
-// revert(validateJo_i_290, validateJo__34)
+// mstore(validateJo_i_1306, 400)
+// revert(validateJo_i_1306, validateJo__34)
// }
// validateJo_b := add(validateJo_b, validateJo__52)
// }
@@ -340,13 +336,13 @@
// }
// if iszero(eq(mod(keccak256(validateJo__24, add(validateJo_b, 0xfffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffd60)), validateJo_gen_order), validateJo_challenge))
// {
-// mstore(validateJo_i_290, 404)
-// revert(validateJo_i_290, 0x20)
+// mstore(validateJo_i_1306, 404)
+// revert(validateJo_i_1306, 0x20)
// }
-// mstore(validateJo_i_290, 0x01)
-// return(validateJo_i_290, 0x20)
-// mstore(validateJo_i_290, 404)
-// revert(validateJo_i_290, 0x20)
+// mstore(validateJo_i_1306, 0x01)
+// return(validateJo_i_1306, 0x20)
+// mstore(validateJo_i_1306, 404)
+// revert(validateJo_i_1306, 0x20)
// function validatePairing(t2)
// {
// let t2_x_1 := calldataload(t2)
diff --git a/test/libyul/yulOptimizerTests/fullSuite/medium.yul b/test/libyul/yulOptimizerTests/fullSuite/medium.yul
index b10c6c69..1d07cd03 100644
--- a/test/libyul/yulOptimizerTests/fullSuite/medium.yul
+++ b/test/libyul/yulOptimizerTests/fullSuite/medium.yul
@@ -21,8 +21,8 @@
// {
// let allocate__19 := 0x40
// mstore(allocate__19, add(mload(allocate__19), 0x20))
-// let allocate_p_24_41 := mload(allocate__19)
-// mstore(allocate__19, add(allocate_p_24_41, allocate__19))
-// mstore(add(allocate_p_24_41, 96), 2)
+// let allocate_p_35_39 := mload(allocate__19)
+// mstore(allocate__19, add(allocate_p_35_39, allocate__19))
+// mstore(add(allocate_p_35_39, 96), 2)
// mstore(allocate__19, 0x20)
// }
diff --git a/test/libyul/yulOptimizerTests/fullSuite/ssaReverse.yul b/test/libyul/yulOptimizerTests/fullSuite/ssaReverse.yul
new file mode 100644
index 00000000..204b444e
--- /dev/null
+++ b/test/libyul/yulOptimizerTests/fullSuite/ssaReverse.yul
@@ -0,0 +1,62 @@
+{
+ // This is an abi decode function with the SSA transform applied once.
+ // This test is supposed to verify that the SSA transform is correctly reversed by the full suite.
+ function abi_decode_t_bytes_calldata_ptr(offset_12, end_13) -> arrayPos_14, length_15
+ {
+ if iszero(slt(add(offset_12, 0x1f), end_13))
+ {
+ revert(0, 0)
+ }
+ let length_15_1 := calldataload(offset_12)
+ length_15 := length_15_1
+ if gt(length_15_1, 0xffffffffffffffff)
+ {
+ revert(0, 0)
+ }
+ let arrayPos_14_2 := add(offset_12, 0x20)
+ arrayPos_14 := arrayPos_14_2
+ if gt(add(arrayPos_14_2, mul(length_15_1, 0x1)), end_13)
+ {
+ revert(0, 0)
+ }
+ }
+
+ // prevent inlining
+ let a,b := abi_decode_t_bytes_calldata_ptr(mload(0),mload(1))
+ a,b := abi_decode_t_bytes_calldata_ptr(a,b)
+ a,b := abi_decode_t_bytes_calldata_ptr(a,b)
+ a,b := abi_decode_t_bytes_calldata_ptr(a,b)
+ a,b := abi_decode_t_bytes_calldata_ptr(a,b)
+ a,b := abi_decode_t_bytes_calldata_ptr(a,b)
+ a,b := abi_decode_t_bytes_calldata_ptr(a,b)
+ mstore(a,b)
+}
+// ----
+// fullSuite
+// {
+// let a, b := abi_decode_t_bytes_calldata_ptr(mload(0), mload(1))
+// a, b := abi_decode_t_bytes_calldata_ptr(a, b)
+// a, b := abi_decode_t_bytes_calldata_ptr(a, b)
+// a, b := abi_decode_t_bytes_calldata_ptr(a, b)
+// a, b := abi_decode_t_bytes_calldata_ptr(a, b)
+// a, b := abi_decode_t_bytes_calldata_ptr(a, b)
+// a, b := abi_decode_t_bytes_calldata_ptr(a, b)
+// mstore(a, b)
+// function abi_decode_t_bytes_calldata_ptr(offset_12, end_13) -> arrayPos_14, length_15
+// {
+// if iszero(slt(add(offset_12, 0x1f), end_13))
+// {
+// revert(0, 0)
+// }
+// length_15 := calldataload(offset_12)
+// if gt(length_15, 0xffffffffffffffff)
+// {
+// revert(0, 0)
+// }
+// arrayPos_14 := add(offset_12, 0x20)
+// if gt(add(add(offset_12, length_15), 0x20), end_13)
+// {
+// revert(0, 0)
+// }
+// }
+// }
diff --git a/test/libyul/yulOptimizerTests/fullSuite/ssaReverseComplex.yul b/test/libyul/yulOptimizerTests/fullSuite/ssaReverseComplex.yul
new file mode 100644
index 00000000..2e178f31
--- /dev/null
+++ b/test/libyul/yulOptimizerTests/fullSuite/ssaReverseComplex.yul
@@ -0,0 +1,23 @@
+{
+ let a := mload(0)
+ let b := mload(1)
+ if mload(2) {
+ a := mload(b)
+ b := mload(a)
+ a := mload(b)
+ b := mload(a)
+ }
+ mstore(a, b)
+}
+// ----
+// fullSuite
+// {
+// let a := mload(0)
+// let b := mload(1)
+// if mload(2)
+// {
+// a := mload(mload(mload(b)))
+// b := mload(a)
+// }
+// mstore(a, b)
+// }
diff --git a/test/libyul/yulOptimizerTests/ssaAndBack/for_loop.yul b/test/libyul/yulOptimizerTests/ssaAndBack/for_loop.yul
new file mode 100644
index 00000000..18498e61
--- /dev/null
+++ b/test/libyul/yulOptimizerTests/ssaAndBack/for_loop.yul
@@ -0,0 +1,36 @@
+{
+ for {
+ let a := mload(0)
+ let b := mload(1)
+ }
+ lt(mload(a),mload(b))
+ {
+ a := mload(b)
+ }
+ {
+ b := mload(a)
+ a := mload(b)
+ a := mload(b)
+ a := mload(b)
+ b := mload(a)
+ }
+}
+// ----
+// ssaAndBack
+// {
+// for {
+// let a := mload(0)
+// let b := mload(1)
+// }
+// lt(mload(a), mload(b))
+// {
+// a := mload(b)
+// }
+// {
+// let b_3 := mload(a)
+// pop(mload(b_3))
+// pop(mload(b_3))
+// let a_6 := mload(b_3)
+// b := mload(a_6)
+// }
+// }
diff --git a/test/libyul/yulOptimizerTests/ssaAndBack/multi_assign.yul b/test/libyul/yulOptimizerTests/ssaAndBack/multi_assign.yul
new file mode 100644
index 00000000..23c433d1
--- /dev/null
+++ b/test/libyul/yulOptimizerTests/ssaAndBack/multi_assign.yul
@@ -0,0 +1,18 @@
+{
+ let a := mload(0)
+ a := mload(1)
+ a := mload(2)
+ a := mload(3)
+ a := mload(4)
+ mstore(a, 0)
+}
+// ----
+// ssaAndBack
+// {
+// pop(mload(0))
+// pop(mload(1))
+// pop(mload(2))
+// pop(mload(3))
+// let a_5 := mload(4)
+// mstore(a_5, 0)
+// }
diff --git a/test/libyul/yulOptimizerTests/ssaAndBack/multi_assign_if.yul b/test/libyul/yulOptimizerTests/ssaAndBack/multi_assign_if.yul
new file mode 100644
index 00000000..fd5981ef
--- /dev/null
+++ b/test/libyul/yulOptimizerTests/ssaAndBack/multi_assign_if.yul
@@ -0,0 +1,22 @@
+{
+ let a := mload(0)
+ if mload(1)
+ {
+ a := mload(1)
+ a := mload(2)
+ a := mload(3)
+ }
+ mstore(a, 0)
+}
+// ----
+// ssaAndBack
+// {
+// let a := mload(0)
+// if mload(1)
+// {
+// pop(mload(1))
+// pop(mload(2))
+// a := mload(3)
+// }
+// mstore(a, 0)
+// }
diff --git a/test/libyul/yulOptimizerTests/ssaAndBack/multi_assign_multi_var_if.yul b/test/libyul/yulOptimizerTests/ssaAndBack/multi_assign_multi_var_if.yul
new file mode 100644
index 00000000..b0b3efb5
--- /dev/null
+++ b/test/libyul/yulOptimizerTests/ssaAndBack/multi_assign_multi_var_if.yul
@@ -0,0 +1,25 @@
+{
+ let a := mload(0)
+ let b := mload(1)
+ if mload(2) {
+ a := mload(b)
+ b := mload(a)
+ a := mload(b)
+ b := mload(a)
+ }
+ mstore(a, b)
+}
+// ----
+// ssaAndBack
+// {
+// let a := mload(0)
+// let b := mload(1)
+// if mload(2)
+// {
+// let a_3 := mload(b)
+// let b_4 := mload(a_3)
+// a := mload(b_4)
+// b := mload(a)
+// }
+// mstore(a, b)
+// }
diff --git a/test/libyul/yulOptimizerTests/ssaAndBack/multi_assign_multi_var_switch.yul b/test/libyul/yulOptimizerTests/ssaAndBack/multi_assign_multi_var_switch.yul
new file mode 100644
index 00000000..50f56b87
--- /dev/null
+++ b/test/libyul/yulOptimizerTests/ssaAndBack/multi_assign_multi_var_switch.yul
@@ -0,0 +1,38 @@
+{
+ let a := mload(0)
+ let b := mload(1)
+ switch mload(2)
+ case 0 {
+ a := mload(b)
+ b := mload(a)
+ a := mload(b)
+ b := mload(a)
+ }
+ default {
+ b := mload(a)
+ a := mload(b)
+ b := mload(a)
+ a := mload(b)
+ }
+ mstore(a, b)
+}
+// ----
+// ssaAndBack
+// {
+// let a := mload(0)
+// let b := mload(1)
+// switch mload(2)
+// case 0 {
+// let a_3 := mload(b)
+// let b_4 := mload(a_3)
+// a := mload(b_4)
+// b := mload(a)
+// }
+// default {
+// let b_7 := mload(a)
+// let a_8 := mload(b_7)
+// b := mload(a_8)
+// a := mload(b)
+// }
+// mstore(a, b)
+// }
diff --git a/test/libyul/yulOptimizerTests/ssaAndBack/multi_assign_switch.yul b/test/libyul/yulOptimizerTests/ssaAndBack/multi_assign_switch.yul
new file mode 100644
index 00000000..1efbbde7
--- /dev/null
+++ b/test/libyul/yulOptimizerTests/ssaAndBack/multi_assign_switch.yul
@@ -0,0 +1,32 @@
+{
+ let a := mload(0)
+ switch mload(1)
+ case 0 {
+ a := mload(1)
+ a := mload(2)
+ a := mload(3)
+ }
+ default {
+ a := mload(4)
+ a := mload(5)
+ a := mload(6)
+ }
+ mstore(a, 0)
+}
+// ----
+// ssaAndBack
+// {
+// let a := mload(0)
+// switch mload(1)
+// case 0 {
+// pop(mload(1))
+// pop(mload(2))
+// a := mload(3)
+// }
+// default {
+// pop(mload(4))
+// pop(mload(5))
+// a := mload(6)
+// }
+// mstore(a, 0)
+// }
diff --git a/test/libyul/yulOptimizerTests/ssaAndBack/simple.yul b/test/libyul/yulOptimizerTests/ssaAndBack/simple.yul
new file mode 100644
index 00000000..912940c5
--- /dev/null
+++ b/test/libyul/yulOptimizerTests/ssaAndBack/simple.yul
@@ -0,0 +1,12 @@
+{
+ let a := mload(0)
+ a := mload(1)
+ mstore(a, 0)
+}
+// ----
+// ssaAndBack
+// {
+// pop(mload(0))
+// let a_2 := mload(1)
+// mstore(a_2, 0)
+// }
diff --git a/test/libyul/yulOptimizerTests/ssaAndBack/single_assign_if.yul b/test/libyul/yulOptimizerTests/ssaAndBack/single_assign_if.yul
new file mode 100644
index 00000000..5185245c
--- /dev/null
+++ b/test/libyul/yulOptimizerTests/ssaAndBack/single_assign_if.yul
@@ -0,0 +1,18 @@
+{
+ let a := mload(0)
+ if mload(1)
+ {
+ a := mload(1)
+ }
+ mstore(a, 0)
+}
+// ----
+// ssaAndBack
+// {
+// let a := mload(0)
+// if mload(1)
+// {
+// a := mload(1)
+// }
+// mstore(a, 0)
+// }
diff --git a/test/libyul/yulOptimizerTests/ssaAndBack/single_assign_switch.yul b/test/libyul/yulOptimizerTests/ssaAndBack/single_assign_switch.yul
new file mode 100644
index 00000000..e0e53b3f
--- /dev/null
+++ b/test/libyul/yulOptimizerTests/ssaAndBack/single_assign_switch.yul
@@ -0,0 +1,24 @@
+{
+ let a := mload(0)
+ switch mload(1)
+ case 0 {
+ a := mload(1)
+ }
+ default {
+ a := mload(2)
+ }
+ mstore(a, 0)
+}
+// ----
+// ssaAndBack
+// {
+// let a := mload(0)
+// switch mload(1)
+// case 0 {
+// a := mload(1)
+// }
+// default {
+// a := mload(2)
+// }
+// mstore(a, 0)
+// }
diff --git a/test/libyul/yulOptimizerTests/ssaAndBack/ssaReverse.yul b/test/libyul/yulOptimizerTests/ssaAndBack/ssaReverse.yul
new file mode 100644
index 00000000..d2ba6471
--- /dev/null
+++ b/test/libyul/yulOptimizerTests/ssaAndBack/ssaReverse.yul
@@ -0,0 +1,45 @@
+{
+ function abi_decode_t_bytes_calldata_ptr(offset_12, end_13) -> arrayPos_14, length_15
+ {
+ if iszero(slt(add(offset_12, 0x1f), end_13))
+ {
+ revert(0, 0)
+ }
+ length_15 := calldataload(offset_12)
+ if gt(length_15, 0xffffffffffffffff)
+ {
+ revert(0, 0)
+ }
+ arrayPos_14 := add(offset_12, 0x20)
+ if gt(add(add(offset_12, length_15), 0x20), end_13)
+ {
+ revert(0, 0)
+ }
+ }
+ // prevent removal of the function
+ let a,b := abi_decode_t_bytes_calldata_ptr(mload(0),mload(1))
+ mstore(a,b)
+}
+// ----
+// ssaAndBack
+// {
+// function abi_decode_t_bytes_calldata_ptr(offset_12, end_13) -> arrayPos_14, length_15
+// {
+// if iszero(slt(add(offset_12, 0x1f), end_13))
+// {
+// revert(arrayPos_14, arrayPos_14)
+// }
+// length_15 := calldataload(offset_12)
+// if gt(length_15, 0xffffffffffffffff)
+// {
+// revert(arrayPos_14, arrayPos_14)
+// }
+// arrayPos_14 := add(offset_12, 0x20)
+// if gt(add(add(offset_12, length_15), 0x20), end_13)
+// {
+// revert(0, 0)
+// }
+// }
+// let a, b := abi_decode_t_bytes_calldata_ptr(mload(0), mload(1))
+// mstore(a, b)
+// }
diff --git a/test/libyul/yulOptimizerTests/ssaAndBack/two_vars.yul b/test/libyul/yulOptimizerTests/ssaAndBack/two_vars.yul
new file mode 100644
index 00000000..9f2a046e
--- /dev/null
+++ b/test/libyul/yulOptimizerTests/ssaAndBack/two_vars.yul
@@ -0,0 +1,20 @@
+{
+ let a := mload(0)
+ let b := mload(a)
+ a := mload(b)
+ b := mload(a)
+ a := mload(b)
+ b := mload(a)
+ mstore(a, b)
+}
+// ----
+// ssaAndBack
+// {
+// let a_1 := mload(0)
+// let b_2 := mload(a_1)
+// let a_3 := mload(b_2)
+// let b_4 := mload(a_3)
+// let a_5 := mload(b_4)
+// let b_6 := mload(a_5)
+// mstore(a_5, b_6)
+// }
diff --git a/test/libyul/yulOptimizerTests/ssaReverser/abi_example.yul b/test/libyul/yulOptimizerTests/ssaReverser/abi_example.yul
new file mode 100644
index 00000000..923a42ba
--- /dev/null
+++ b/test/libyul/yulOptimizerTests/ssaReverser/abi_example.yul
@@ -0,0 +1,44 @@
+{
+ function abi_decode_t_bytes_calldata_ptr(offset_12, end_13) -> arrayPos_14, length_15
+ {
+ if iszero(slt(add(offset_12, 0x1f), end_13))
+ {
+ revert(0, 0)
+ }
+ let length_15_1 := calldataload(offset_12)
+ length_15 := length_15_1
+ if gt(length_15_1, 0xffffffffffffffff)
+ {
+ revert(0, 0)
+ }
+ let arrayPos_14_2 := add(offset_12, 0x20)
+ arrayPos_14 := arrayPos_14_2
+ if gt(add(arrayPos_14_2, mul(length_15_1, 0x1)), end_13)
+ {
+ revert(0, 0)
+ }
+ }
+}
+// ----
+// ssaReverser
+// {
+// function abi_decode_t_bytes_calldata_ptr(offset_12, end_13) -> arrayPos_14, length_15
+// {
+// if iszero(slt(add(offset_12, 0x1f), end_13))
+// {
+// revert(0, 0)
+// }
+// length_15 := calldataload(offset_12)
+// let length_15_1 := length_15
+// if gt(length_15_1, 0xffffffffffffffff)
+// {
+// revert(0, 0)
+// }
+// arrayPos_14 := add(offset_12, 0x20)
+// let arrayPos_14_2 := arrayPos_14
+// if gt(add(arrayPos_14_2, mul(length_15_1, 0x1)), end_13)
+// {
+// revert(0, 0)
+// }
+// }
+// }
diff --git a/test/libyul/yulOptimizerTests/ssaReverser/simple.yul b/test/libyul/yulOptimizerTests/ssaReverser/simple.yul
new file mode 100644
index 00000000..eba1f5f1
--- /dev/null
+++ b/test/libyul/yulOptimizerTests/ssaReverser/simple.yul
@@ -0,0 +1,14 @@
+{
+ let a := mload(1)
+ let a_1 := mload(0)
+ a := a_1
+ mstore(a_1, 0)
+}
+// ----
+// ssaReverser
+// {
+// let a := mload(1)
+// a := mload(0)
+// let a_1 := a
+// mstore(a_1, 0)
+// }
diff --git a/test/tools/yulopti.cpp b/test/tools/yulopti.cpp
index efd1ba05..7203ef54 100644
--- a/test/tools/yulopti.cpp
+++ b/test/tools/yulopti.cpp
@@ -46,6 +46,7 @@
#include <libyul/optimiser/UnusedPruner.h>
#include <libyul/optimiser/ExpressionJoiner.h>
#include <libyul/optimiser/RedundantAssignEliminator.h>
+#include <libyul/optimiser/SSAReverser.h>
#include <libyul/optimiser/SSATransform.h>
#include <libyul/optimiser/StructuralSimplifier.h>
#include <libyul/optimiser/VarDeclInitializer.h>
@@ -129,7 +130,7 @@ public:
cout << "(q)quit/(f)flatten/(c)se/initialize var(d)ecls/(x)plit/(j)oin/(g)rouper/(h)oister/" << endl;
cout << " (e)xpr inline/(i)nline/(s)implify/(u)nusedprune/ss(a) transform/" << endl;
cout << " (r)edundant assign elim./re(m)aterializer/f(o)r-loop-pre-rewriter/" << endl;
- cout << " s(t)ructural simplifier/equi(v)alent function combiner? " << endl;
+ cout << " s(t)ructural simplifier/equi(v)alent function combiner/ssa re(V)erser? " << endl;
cout.flush();
int option = readStandardInputChar();
cout << ' ' << char(option) << endl;
@@ -188,6 +189,9 @@ public:
case 'v':
EquivalentFunctionCombiner::run(*m_ast);
break;
+ case 'V':
+ SSAReverser::run(*m_ast);
+ break;
default:
cout << "Unknown option." << endl;
}