bool CopyPropagationPass2::IsOnlyDefinition(StoreVariableStatement* def,
LoadVariableExpression* use)
{
BrickAnnote* defAnnote =
to<BrickAnnote>(use->lookup_annote_by_name("reaching_defs")) ;
assert(defAnnote != NULL) ;
if (defAnnote->get_brick_count() != 1)
{
return false ;
}
SuifBrick* defBrick = defAnnote->get_brick(0) ;
SuifObjectBrick* sob = dynamic_cast<SuifObjectBrick*>(defBrick) ;
assert(sob != NULL) ;
if (def == sob->get_object())
{
return true ;
}
else
{
return false ;
}
}
void CopyPropagationPass2::ProcessSpecialIfs()
{
list<IfStatement*>* allIfs =
collect_objects<IfStatement>(procDef->get_body()) ;
assert(allIfs != NULL) ;
list<IfStatement*>::iterator ifIter = allIfs->begin() ;
while (ifIter != allIfs->end())
{
Statement* elsePart = (*ifIter)->get_else_part() ;
assert(elsePart != NULL) ;
StatementList* elseList = dynamic_cast<StatementList*>(elsePart) ;
if (elseList == NULL)
{
++ifIter ;
continue ;
}
assert(elseList != NULL) ;
if (elseList->get_statement_count() == 2)
{
// Process this if statement
Statement* thenPart = (*ifIter)->get_then_part() ;
assert(thenPart != NULL) ;
/*
StatementList* thenList = dynamic_cast<StatementList*>(thenPart) ;
assert(thenList != NULL) ;
assert(thenList->get_statement_count() == 1) ;
Statement* thenStatement = thenList->get_statement(0) ;
assert(thenStatement != NULL) ;
*/
StoreVariableStatement* thenStoreVar =
dynamic_cast<StoreVariableStatement*>(thenPart) ;
assert(thenStoreVar != NULL) ;
Statement* firstElseStatement = elseList->get_statement(0) ;
Statement* secondElseStatement = elseList->get_statement(1) ;
assert(firstElseStatement != NULL && secondElseStatement != NULL) ;
// We are definitely going to break the rules here
// We know that the destination has to be replaced with
// the source
StoreVariableStatement* secondElseStore =
dynamic_cast<StoreVariableStatement*>(secondElseStatement) ;
assert(secondElseStore != NULL) ;
Expression* source = secondElseStore->get_value() ;
assert(source != NULL) ;
LoadVariableExpression* sourceLoadExp =
dynamic_cast<LoadVariableExpression*>(source) ;
assert(sourceLoadExp != NULL) ;
VariableSymbol* sourceVariable = sourceLoadExp->get_source() ;
assert(sourceVariable != NULL) ;
// First, find the use of the then portion and replace that use
// with the source variable
BrickAnnote* ba =
to<BrickAnnote>(thenStoreVar->lookup_annote_by_name("reached_uses")) ;
assert(ba != NULL) ;
assert(ba->get_brick_count() == 1) ;
Iter<SuifBrick*> tmpIter = ba->get_brick_iterator() ;
SuifObjectBrick* sob =
to<SuifObjectBrick>(tmpIter.current()) ;
assert(sob != NULL) ;
SuifObject* finalDest = sob->get_object() ;
LoadVariableExpression* finalLoad =
dynamic_cast<LoadVariableExpression*>(finalDest) ;
assert(finalLoad != NULL) ;
// Before we make the change, mark the variable we are replacing as
// removed.
finalLoad->get_source()->append_annote(create_brick_annote(theEnv, "RemovedVariable")) ;
finalLoad->set_source(sourceVariable) ;
// Now, change the then portion
thenStoreVar->set_destination(sourceVariable) ;
// Now, remove the second else statement
elseList->remove_statement(1) ;
// We should be done.
}
++ifIter ;
}
delete allIfs ;
}