C++ AstIf::condp方法代码示例

    void replaceCaseComplicated(AstCase* nodep) {
	// CASEx(cexpr,ITEM(icond1,istmts1),ITEM(icond2,istmts2),ITEM(default,istmts3))
	// ->  IF((cexpr==icond1),istmts1,
	//		         IF((EQ (AND MASK cexpr) (AND MASK icond1)
	//				,istmts2, istmts3
	AstNode* cexprp = nodep->exprp()->unlinkFrBack();
	// We'll do this in two stages.  First stage, convert the conditions to
	// the appropriate IF AND terms.
	if (debug()>=9) nodep->dumpTree(cout,"    _comp_IN:   ");
	bool hadDefault = false;
	for (AstCaseItem* itemp = nodep->itemsp(); itemp; itemp=itemp->nextp()->castCaseItem()) {
	    if (!itemp->condsp()) {
		// Default clause.  Just make true, we'll optimize it away later
		itemp->condsp(new AstConst(itemp->fileline(), AstConst::LogicTrue()));
		hadDefault = true;
	    } else {
		// Expressioned clause
		AstNode* icondNextp = NULL;
		AstNode* ifexprp = NULL;	// If expression to test
		for (AstNode* icondp = itemp->condsp(); icondp!=NULL; icondp=icondNextp) {
		    icondNextp = icondp->nextp();
		    icondp->unlinkFrBack();

		    AstNode* condp = NULL;  // Default is to use and1p/and2p
		    AstConst* iconstp = icondp->castConst();
		    if (iconstp && neverItem(nodep, iconstp)) {
			// X in casez can't ever be executed
			icondp->deleteTree(); icondp=NULL; iconstp=NULL;
			// For simplicity, make expression that is not equal, and let later
			// optimizations remove it
			condp = new AstConst(itemp->fileline(), AstConst::LogicFalse());
		    } else if (AstInsideRange* irangep = icondp->castInsideRange()) {
			// Similar logic in V3Width::visit(AstInside)
			AstNode* ap = AstGte::newTyped(itemp->fileline(),
						       cexprp->cloneTree(false),
						       irangep->lhsp()->unlinkFrBack());
			AstNode* bp = AstLte::newTyped(itemp->fileline(),
						       cexprp->cloneTree(false),
						       irangep->rhsp()->unlinkFrBack());
			condp = new AstAnd(itemp->fileline(), ap, bp);
		    } else if (iconstp && iconstp->num().isFourState()
			       && (nodep->casex() || nodep->casez() || nodep->caseInside())) {
			V3Number nummask (itemp->fileline(), iconstp->width());
			nummask.opBitsNonX(iconstp->num());
			V3Number numval  (itemp->fileline(), iconstp->width());
			numval.opBitsOne(iconstp->num());
			AstNode* and1p = new AstAnd(itemp->fileline(), cexprp->cloneTree(false),
						    new AstConst(itemp->fileline(), nummask));
			AstNode* and2p = new AstAnd(itemp->fileline(),
						    new AstConst(itemp->fileline(), numval),
						    new AstConst(itemp->fileline(), nummask));
			icondp->deleteTree(); icondp=NULL; iconstp=NULL;
			condp = AstEq::newTyped(itemp->fileline(), and1p, and2p);
		    } else {
			// Not a caseX mask, we can simply build CASEEQ(cexpr icond)
			AstNode* and1p = cexprp->cloneTree(false);
			AstNode* and2p = icondp;
			condp = AstEq::newTyped(itemp->fileline(), and1p, and2p);
		    }
		    if (!ifexprp) {
			ifexprp = condp;
		    } else {
			ifexprp = new AstLogOr(itemp->fileline(), ifexprp, condp);
		    }
		}
		// Replace expression in tree
		itemp->condsp(ifexprp);
	    }
	}
	cexprp->deleteTree(); cexprp=NULL;
	if (!hadDefault) {
	    // If there was no default, add a empty one, this greatly simplifies below code
	    // and constant propagation will just eliminate it for us later.
	    nodep->addItemsp(new AstCaseItem(nodep->fileline(),
					     new AstConst(nodep->fileline(), AstConst::LogicTrue()),
					     NULL));
	}
	if (debug()>=9) nodep->dumpTree(cout,"    _comp_COND: ");
	// Now build the IF statement tree
	// The tree can be quite huge.  Pull ever group of 8 out, and make a OR tree.
	// This reduces the depth for the bottom elements, at the cost of some of the top elements.
	// If we ever have profiling data, we should pull out the most common item from here and
	// instead make it the first IF branch.
	int depth = 0;
	AstNode* grouprootp = NULL;
	AstIf* groupnextp = NULL;
	AstIf* itemnextp = NULL;
	for (AstCaseItem* itemp = nodep->itemsp(); itemp; itemp=itemp->nextp()->castCaseItem()) {
	    AstNode* istmtsp = itemp->bodysp();   // Maybe null -- no action.
	    if (istmtsp) istmtsp->unlinkFrBackWithNext();
	    // Expressioned clause
	    AstNode* ifexprp = itemp->condsp()->unlinkFrBack();
	    {   // Prepare for next group
		if (++depth > CASE_ENCODER_GROUP_DEPTH) depth = 1;
		if (depth == 1) {  // First group or starting new group
		    itemnextp = NULL;
		    AstIf* newp = new AstIf(itemp->fileline(), ifexprp->cloneTree(true), NULL, NULL);
		    if (groupnextp) groupnextp->addElsesp(newp);
		    else grouprootp = newp;
		    groupnextp = newp;
//.........这里部分代码省略.........