shithub: scc

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Simplify expression like *& or &*

This kind of expressions are common in array expressions
and the can simplify a lot the IR generated.

--- a/cc1/expr.c

+++ b/cc1/expr.c

@@ -358,6 +358,12 @@

 	switch (tp->op) {

 	case ARY:

 		tp = tp->type;

+		if (np->op == OPTR) {

+			Node *new = np->left;

+			free(np);

+			new->type = mktype(tp, PTR, 0, NULL);

+			return new;

+		}

 	case FTN:

 		break;

 	default:

@@ -539,14 +545,16 @@

 	}

 	if (BTYPE(rp) != INT)

 		goto incorrect;

+

 	rp = convert(promote(rp), sizettype, 0);

-	rp = node(OMUL, sizettype, rp, size);

-	rp = node(OCAST, tp, rp, NULL);

+	rp = simplify(OMUL, sizettype, rp, size);

+	rp = convert(rp, tp, 1);

-	return node(OADD, tp, lp, rp);

+	return simplify(OADD, tp, lp, rp);

 incorrect:

-	error("incorrect arithmetic operands");

+	errorp("incorrect arithmetic operands");

+	return node(OADD, tp, lp, rp);

 }

 static Node *

@@ -752,6 +760,11 @@

 		error("lvalue required in unary expression");

 	if (np->symbol && (np->sym->flags & ISREGISTER))

 		error("address of register variable '%s' requested", yytext);

+	if (np->op == OPTR) {

+		Node *new = np->left;

+		free(np);

+		return new;

+	}

 	return node(op, mktype(np->type, PTR, 0, NULL), np, NULL);

 }

@@ -761,8 +774,12 @@

 	switch (BTYPE(np)) {

 	case ARY:

 	case FTN:

-		np = decay(np);

 	case PTR:

+		if (np->op == OADDR) {

+			Node *new = np->left;

+			free(np);

+			return new;

+		}

 		np = node(op, np->type->type, np, NULL);

 		np->lvalue = 1;

 		return np;