private bool ReplacePushDupPushPopPattern(BlockStatement b) {
Contract.Requires(b != null);
bool replacedPattern = false;
var statements = b.Statements;
for (int i = 0; i < statements.Count-4; i++) {
var push1 = statements[i] as PushStatement;
if (push1 == null) continue;
var exprS1 = statements[i+1] as ExpressionStatement;
if (exprS1 == null) continue;
var assign1 = exprS1.Expression as Assignment;
if (assign1 == null) continue;
if (!(assign1.Source is DupValue) || assign1.Target.Instance != null) continue;
var push2 = statements[i+2] as PushStatement;
if (push2 == null) continue;
var popCounter = new PopCounter();
popCounter.Traverse(push2);
if (popCounter.count != 1) continue;
if (!this.singleUseExpressionChecker.ExpressionCanBeMovedAndDoesNotReference(push1.ValueToPush, assign1.Target.Definition)) continue;
assign1.Source = push1.ValueToPush;
var popReplacer = new SinglePopReplacer(this.host, assign1);
popReplacer.Rewrite(push2.ValueToPush);
statements.RemoveRange(i, 2);
replacedPattern = true;
}
return replacedPattern;
}
private bool ReplacePushDupPopPattern(BlockStatement b) {
Contract.Requires(b != null);
bool replacedPattern = false;
var statements = b.Statements;
for (int i = 0; i < statements.Count-3; i++) {
var push1 = statements[i] as PushStatement;
if (push1 == null) continue;
var binop1 = push1.ValueToPush as BinaryOperation;
if (binop1 == null) continue;
var bound1 = binop1.LeftOperand as BoundExpression;
if (bound1 == null) continue;
var exprS1 = statements[i+1] as ExpressionStatement;
if (exprS1 == null) continue;
var assign1 = exprS1.Expression as Assignment;
if (assign1 == null) continue;
if (assign1.Target.Definition != bound1.Definition) continue;
if (assign1.Target.Instance != bound1.Instance) {
if (!(assign1.Target.Instance is IPopValue && bound1.Instance is IDupValue)) continue;
}
if (!(assign1.Source is DupValue)) continue;
var statement = statements[i+2] as Statement;
if (statement == null) continue;
var popCounter = new PopCounter();
popCounter.Traverse(statement);
if (popCounter.count != 1) continue;
binop1.LeftOperand = assign1.Target;
var popReplacer = new SinglePopReplacer(this.host, binop1);
popReplacer.Rewrite(statement);
statements.RemoveRange(i, 2);
replacedPattern = true;
}
return replacedPattern;
}
