Merge pull request #16159 from ethereum/SSA-CFG-simpl

SSA-CFG: Tiny code simplifications

Author: blishko

libyul/backends/evm/SSAControlFlowGraphBuilder.cpp

@@ -109,7 +109,7 @@ SSACFG::ValueId SSAControlFlowGraphBuilder::tryRemoveTrivialPhi(SSACFG::ValueId
 
 	m_graph.block(phiInfo->block).phis.erase(_phi);
 
-	std::set<SSACFG::ValueId> phiUses;
+	std::vector<SSACFG::ValueId> phiUses;
 	for (size_t blockIdValue = 0; blockIdValue < m_graph.numBlocks(); ++blockIdValue)
 	{
 		auto& block = m_graph.block(SSACFG::BlockId{blockIdValue});
@@ -126,18 +126,13 @@ SSACFG::ValueId SSAControlFlowGraphBuilder::tryRemoveTrivialPhi(SSACFG::ValueId
 					usedInPhi = true;
 				}
 			if (usedInPhi)
-				phiUses.emplace(blockPhi);
+				phiUses.push_back(blockPhi);
 		}
 		for (auto& op: block.operations)
-			std::replace(op.inputs.begin(), op.inputs.end(), _phi, same);
+			ranges::replace(op.inputs, _phi, same);
 		std::visit(util::GenericVisitor{
 			[_phi, same](SSACFG::BasicBlock::FunctionReturn& _functionReturn) {
-				std::replace(
-					_functionReturn.returnValues.begin(),
-					_functionReturn.returnValues.end(),
-					_phi,
-					same
-				);
+				ranges::replace(_functionReturn.returnValues,_phi, same);
 			},
 			[_phi, same](SSACFG::BasicBlock::ConditionalJump& _condJump) {
 				if (_condJump.condition == _phi)
@@ -188,22 +183,17 @@ void SSAControlFlowGraphBuilder::cleanUnreachable()
 	{
 		auto& block = m_graph.block(blockId);
 
-		std::set<SSACFG::ValueId> maybeTrivialPhi;
-		for (auto it = block.entries.begin(); it != block.entries.end();)
-			if (reachabilityCheck.visited.count(*it))
-				it++;
-			else
-				it = block.entries.erase(it);
+		std::vector<SSACFG::ValueId> maybeTrivialPhi;
+		std::erase_if(block.entries, [&](auto const& entry) { return !reachabilityCheck.visited.contains(entry); });
 		for (auto phi: block.phis)
 			if (auto* phiInfo = std::get_if<SSACFG::PhiValue>(&m_graph.valueInfo(phi)))
-				std::erase_if(phiInfo->arguments, [&](SSACFG::ValueId _arg) {
-					if (std::holds_alternative<SSACFG::UnreachableValue>(m_graph.valueInfo(_arg)))
-					{
-						maybeTrivialPhi.insert(phi);
-						return true;
-					}
-					return false;
+			{
+				auto erasedCount = std::erase_if(phiInfo->arguments, [&](SSACFG::ValueId _arg) {
+					return std::holds_alternative<SSACFG::UnreachableValue>(m_graph.valueInfo(_arg));
 				});
+				if (erasedCount > 0)
+					maybeTrivialPhi.push_back(phi);
+			}
 
 		// After removing a phi argument, we might end up with a trivial phi that can be removed.
 		for (auto phi: maybeTrivialPhi)