Do not allow msize in inline assembly if the Yul optimizer is active.

test/libsolidity/SolidityEndToEndTest.cpp

@@ -10082,8 +10082,11 @@ BOOST_AUTO_TEST_CASE(create_memory_array_allocation_size)
 			}
 		}
 	)";
-	compileAndRun(sourceCode);
-	ABI_CHECK(callContractFunction("f()"), encodeArgs(0x40, 0x40, 0x20 + 256, 0x260));
+	if (!m_optimiserSettings.runYulOptimiser)
+	{
+		compileAndRun(sourceCode);
+		ABI_CHECK(callContractFunction("f()"), encodeArgs(0x40, 0x40, 0x20 + 256, 0x260));
+	}
 }
 
 BOOST_AUTO_TEST_CASE(memory_arrays_of_various_sizes)
@@ -11273,8 +11276,12 @@ BOOST_AUTO_TEST_CASE(correctly_initialize_memory_array_in_constructor)
 			}
 		}
 	)";
-	compileAndRun(sourceCode, 0, "C");
-	ABI_CHECK(callContractFunction("success()"), encodeArgs(u256(1)));
+	// Cannot run against yul optimizer because of msize
+	if (!m_optimiserSettings.runYulOptimiser)
+	{
+		compileAndRun(sourceCode, 0, "C");
+		ABI_CHECK(callContractFunction("success()"), encodeArgs(u256(1)));
+	}
 }
 
 BOOST_AUTO_TEST_CASE(return_does_not_skip_modifier)

test/libsolidity/SyntaxTest.cpp

@@ -60,6 +60,12 @@ SyntaxTest::SyntaxTest(string const& _filename, langutil::EVMVersion _evmVersion
 	file.exceptions(ios::badbit);
 
 	m_source = parseSourceAndSettings(file);
+	if (m_settings.count("optimize-yul"))
+	{
+		m_optimiseYul = true;
+		m_validatedSettings["optimize-yul"] = "true";
+		m_settings.erase("optimize-yul");
+	}
 	m_expectations = parseExpectations(file);
 }
 
@@ -69,7 +75,11 @@ TestCase::TestResult SyntaxTest::run(ostream& _stream, string const& _linePrefix
 	compiler().reset();
 	compiler().setSources({{"", versionPragma + m_source}});
 	compiler().setEVMVersion(m_evmVersion);
-
+	compiler().setOptimiserSettings(
+		m_optimiseYul ?
+		OptimiserSettings::full() :
+		OptimiserSettings::minimal()
+	);
 	if (compiler().parse())
 		compiler().analyze();
 

test/libsolidity/SyntaxTest.h

@@ -82,6 +82,7 @@ protected:
 	std::string m_source;
 	std::vector<SyntaxTestError> m_expectations;
 	std::vector<SyntaxTestError> m_errorList;
+	bool m_optimiseYul = false;
 	langutil::EVMVersion const m_evmVersion;
 };
 

test/libsolidity/syntaxTests/inlineAssembly/use_msize_with_optimizer.sol

@@ -0,0 +1,12 @@
+contract C {
+    function f() pure public {
+        assembly {
+            let x := msize()
+        }
+    }
+}
+// ====
+// optimize-yul: true
+// ----
+// Warning: The Yul optimiser is still experimental. Do not use it in production unless correctness of generated code is verified with extensive tests.
+// SyntaxError: (52-101): The msize instruction cannot be used when the Yul optimizer is activated because it can change its semantics. Either disable the Yul optimizer or do not use the instruction.

test/libsolidity/syntaxTests/inlineAssembly/use_msize_without_optimizer.sol

@@ -0,0 +1,8 @@
+contract C {
+    function f() pure public {
+        assembly {
+            let x := msize()
+        }
+    }
+}
+// ----

test/libyul/yulOptimizerTests/unusedPruner/keccak.yul

@@ -0,0 +1,12 @@
+{
+    let a := 1
+    let b := keccak256(1, 1)
+    sstore(0, msize())
+}
+// ====
+// step: unusedPruner
+// ----
+// {
+//     pop(keccak256(1, 1))
+//     sstore(0, msize())
+// }