shithub: scc

Info  •  Files  •  Log  •  Branches

cc1: Fold unary expressions

Simplify was just calling foldunary() in case of a unary
operator, which tries simple unary simplifications, like
for example double negation. The code was missing callng
fold() to enable constant folding.

--- a/src/cmd/cc/cc1/fold.c

+++ b/src/cmd/cc/cc1/fold.c

@@ -422,7 +422,6 @@

 	Node *p, *lp = np->left, *rp = np->right;

 	Type *tp = np->type;

-	assert(lp && rp);

 	if ((op == ODIV || op == OMOD) && cmpnode(rp, 0)) {

 		warn("division by 0");

 		return NULL;

@@ -442,12 +441,13 @@

 		rs = rp->sym;

 	}

-	if (!(lp->flags & NCONST) || !lp->sym)

+	if ((lp->flags & NCONST) == 0 || !lp->sym)

 		return NULL;

 	optype = lp->type;

 	ls = lp->sym;

-	switch (type = optype->op) {

+	type = optype->op;

+	switch (type) {

 	case ENUM:

 	case INT:

 		if (!(optype->prop & TSIGNED))

@@ -671,6 +671,8 @@

 	case ONEG:

 		assert(!r);

 		if ((p = foldunary(np, l)) != NULL)

+			return p;

+		if ((p = fold(np)) != NULL)

 			return p;

 		return np;

 	default: