Merge pull request #7425 from ethereum/fixOrderOpt

Fix order bug in optimizer.

Changelog.md

@@ -14,6 +14,7 @@ Compiler Features:
 
 Bugfixes:
  * Fix internal error when popping a dynamic storage array of mappings.
+ * Yul Optimizer: Fix reordering bug in connection with shifted one and mul/div-instructions in for loop conditions.
 
 
 ### 0.5.11 (2019-08-12)

libevmasm/RuleList.h

@@ -475,7 +475,8 @@ std::vector<SimplificationRule<Pattern>> simplificationRuleListPart7(
 		[=]() -> Pattern {
 			return {Instruction::SHL, {Y, X}};
 		},
-		false
+		// Actually only changes the order, does not remove.
+		true
 	});
 	rules.push_back({
 		// MUL(SHL(X, 1), Y) -> SHL(X, Y)
@@ -492,7 +493,8 @@ std::vector<SimplificationRule<Pattern>> simplificationRuleListPart7(
 		[=]() -> Pattern {
 			return {Instruction::SHR, {Y, X}};
 		},
-		false
+		// Actually only changes the order, does not remove.
+		true
 	});
 
 	std::function<bool()> feasibilityFunction = [=]() {

test/libyul/yulOptimizerTests/expressionSimplifier/side_effects_in_for_condition.yul

@@ -0,0 +1,13 @@
+{
+  for {} div(create(0, 1, 0), shl(msize(), 1)) {}
+  {
+  }
+}
+// ====
+// step: expressionSimplifier
+// EVMVersion: >byzantium
+// ----
+// {
+//     for { } div(create(0, 1, 0), shl(msize(), 1)) { }
+//     { }
+// }