Merge pull request #792 from chriseth/optimizer

Further fixes to the optimizer.

3 files changed, 9 insertions, 5 deletions

diff --git a/libevmasm/ControlFlowGraph.cpp b/libevmasm/ControlFlowGraph.cpp
index 61b24e4b..d4801562 100644
--- a/libevmasm/ControlFlowGraph.cpp
+++ b/libevmasm/ControlFlowGraph.cpp
@@ -250,10 +250,11 @@ void ControlFlowGraph::gatherKnowledge()
 		KnownStatePointer state = item.state;
 		if (block.startState)
 		{
-			if (m_joinKnowledge)
-				state->reduceToCommonKnowledge(*block.startState, !item.blocksSeen.count(item.blockId));
-			else
+			// We call reduceToCommonKnowledge even in the non-join setting to get the correct
+			// sequence number
+			if (!m_joinKnowledge)
 				state->reset();
+			state->reduceToCommonKnowledge(*block.startState, !item.blocksSeen.count(item.blockId));
 			if (*state == *block.startState)
 				continue;
 		}
diff --git a/libevmasm/ControlFlowGraph.h b/libevmasm/ControlFlowGraph.h
index a6a9df8e..03a1f717 100644
--- a/libevmasm/ControlFlowGraph.h
+++ b/libevmasm/ControlFlowGraph.h
@@ -116,7 +116,7 @@ private:
 
 	unsigned m_lastUsedId = 0;
 	AssemblyItems const& m_items;
-	bool m_joinKnowledge;
+	bool m_joinKnowledge = true;
 	std::map<BlockId, BasicBlock> m_blocks;
 };
 
diff --git a/test/libsolidity/SolidityOptimizer.cpp b/test/libsolidity/SolidityOptimizer.cpp
index 2e4ed4b3..206f23fb 100644
--- a/test/libsolidity/SolidityOptimizer.cpp
+++ b/test/libsolidity/SolidityOptimizer.cpp
@@ -282,6 +282,8 @@ BOOST_AUTO_TEST_CASE(storage_write_in_loops)
 	compareVersions("f(uint256)", 36);
 }
 
+// Test disabled with https://github.com/ethereum/solidity/pull/762
+// Information in joining branches is not retained anymore.
 BOOST_AUTO_TEST_CASE(retain_information_in_branches)
 {
 	// This tests that the optimizer knows that we already have "z == sha3(y)" inside both branches.
@@ -315,7 +317,8 @@ BOOST_AUTO_TEST_CASE(retain_information_in_branches)
 		if (_instr == Instruction::SHA3)
 			numSHA3s++;
 	});
-	BOOST_CHECK_EQUAL(1, numSHA3s);
+// TEST DISABLED - OPTIMIZER IS NOT EFFECTIVE ON THIS ONE ANYMORE
+//	BOOST_CHECK_EQUAL(1, numSHA3s);
 }
 
 BOOST_AUTO_TEST_CASE(store_tags_as_unions)