diff --git a/tools/qfcc/source/expr_algebra.c b/tools/qfcc/source/expr_algebra.c
index 114a6a8e3..4ee35a349 100644
--- a/tools/qfcc/source/expr_algebra.c
+++ b/tools/qfcc/source/expr_algebra.c
@@ -80,15 +80,6 @@ is_neg (const expr_t *e)
 	return e->type == ex_uexpr && e->expr.op == '-';
 }
 
-static expr_t *
-ext_expr (expr_t *src, type_t *type, int extend, bool reverse)
-{
-	if (!src) {
-		return 0;
-	}
-	return edag_add_expr (new_extend_expr (src, type, extend, reverse));
-}
-
 static bool __attribute__((const))
 anti_com (const expr_t *e)
 {
@@ -115,6 +106,24 @@ neg_expr (expr_t *e)
 	return edag_add_expr (fold_constants (e));
 }
 
+static expr_t *
+ext_expr (expr_t *src, type_t *type, int extend, bool reverse)
+{
+	if (!src) {
+		return 0;
+	}
+	bool neg = false;
+	if (is_neg (src)) {
+		neg = true;
+		src = neg_expr (src);
+	}
+	auto ext = edag_add_expr (new_extend_expr (src, type, extend, reverse));
+	if (neg) {
+		ext = neg_expr (ext);
+	}
+	return ext;
+}
+
 static expr_t *
 alias_expr (type_t *type, expr_t *e, int offset)
 {
@@ -353,7 +362,7 @@ mvec_gather (expr_t **components, algebra_t *algebra)
 	}
 	return mvec;
 }
-
+#if 0
 static bool __attribute__((const))
 ext_compat (const expr_t *a, const expr_t *b)
 {
@@ -368,7 +377,7 @@ extract_extended_neg (const expr_t *expr)
 	auto e = expr->extend;
 	return neg_expr (ext_expr (neg_expr (e.src), e.type, e.extend, e.reverse));
 }
-
+#endif
 static __attribute__((pure)) expr_t *
 traverse_scale (expr_t *expr)
 {
@@ -424,102 +433,43 @@ distribute_terms_core (expr_t *sum,
 		distribute_terms_core (e2, adds, addind, subs, subind, subtract);
 	}
 	if (!is_sum (e1)) {
-		if (negative) {
-			subs[(*subind)++] = sum->expr.e1;
-		} else {
-			adds[(*addind)++] = sum->expr.e1;
+		auto e = sum->expr.e1;
+		auto arr = negative ^ is_neg (e) ? subs : adds;
+		auto ind = negative ^ is_neg (e) ? subind : addind;
+		if (is_neg (e)) {
+			e = neg_expr (e);
 		}
+		arr[(*ind)++] = e;
 	}
 	if (!is_sum (e2)) {
-		if (subtract) {
-			subs[(*subind)++] = sum->expr.e2;
-		} else {
-			adds[(*addind)++] = sum->expr.e2;
+		auto e = sum->expr.e2;
+		auto arr = subtract ^ is_neg (e) ? subs : adds;
+		auto ind = subtract ^ is_neg (e) ? subind : addind;
+		if (is_neg (e)) {
+			e = neg_expr (e);
 		}
+		arr[(*ind)++] = e;
 	}
 }
 
 static expr_t *
-sum_expr (type_t *type, expr_t *a, expr_t *b)
+sum_expr_low (type_t *type, int op, expr_t *a, expr_t *b)
 {
 	if (!a) {
-		return b;
+		return op == '-' ? neg_expr (b) : b;
 	}
 	if (!b) {
 		return a;
 	}
-	if (a->type != ex_extend && b->type == ex_extend) {
-		// ensure always ext + something
-		return sum_expr (type, b, a);
-	}
-	if (a->type == ex_extend) {
-		if (b->type == ex_extend) {
-			if (ext_compat (a, b)) {
-				// push the sum below the two extends making for a single
-				// extend of a sum instead of a sum of two extends
-				auto ext = a->extend;
-				a = a->extend.src;
-				b = b->extend.src;
-				auto sum = sum_expr (get_type (a), a, b);
-				return ext_expr (sum, type, ext.extend, ext.reverse);
-			}
-		} else if (b->type == ex_expr && b->expr.op == '+') {
-			auto c = b->expr.e1;
-			auto d = b->expr.e2;
-			if (ext_compat (a, c)) {
-				// d should not be compatible with a because it should have
-				// already been merged
-				auto ext = a->extend;
-				a = a->extend.src;
-				c = c->extend.src;
-				auto sum = sum_expr (get_type (a), a, c);
-				sum = ext_expr (sum, type, ext.extend, ext.reverse);
-				return sum_expr (type, sum, d);
-			}
-			if (ext_compat (a, d)) {
-				// c should not be compatible with a because it should have
-				// already been merged
-				auto ext = a->extend;
-				a = a->extend.src;
-				d = d->extend.src;
-				auto sum = sum_expr (get_type (a), a, d);
-				sum = ext_expr (sum, type, ext.extend, ext.reverse);
-				return sum_expr (type, sum, c);
-			}
-		}
-	}
-	if (a->type == ex_extend && is_neg (a->extend.src)) {
-		a = extract_extended_neg (a);
-	}
-	if (b->type == ex_extend && is_neg (b->extend.src)) {
-		b = extract_extended_neg (b);
-	}
-	bool neg = false;
-	if ((is_neg (a) && (is_neg (b) || anti_com (b)))
-		|| (anti_com (a) && is_neg (b))) {
-		neg = true;
-		a = neg_expr (a);
-		b = neg_expr (b);
-	}
-	int op = '+';
-	if (is_neg (a) && b->type != ex_extend) {
-		auto t = a;
-		a = b;
-		b = t;
-		op = '-';
-		b = neg_expr (b);
-	} else if (a->type != ex_extend && is_neg (b)) {
-		op = '-';
-		b = neg_expr (b);
+	if (op == '-' && a == b) {
+		return 0;
 	}
+
 	auto sum = new_binary_expr (op, a, b);
 	sum->expr.type = type;
 	sum->expr.commutative = op == '+';
 	sum->expr.anticommute = op == '-';
 	sum = edag_add_expr (sum);
-	if (neg) {
-		sum = neg_expr (sum);
-	}
 	return sum;
 }
 
@@ -538,14 +488,56 @@ distribute_terms (expr_t *sum, expr_t **adds, expr_t **subs)
 static expr_t *
 collect_terms (type_t *type, expr_t **adds, expr_t **subs)
 {
+	expr_t *a = 0;
 	expr_t *b = 0;
 	for (auto s = adds; *s; s++) {
-		b = sum_expr (type, b, *s);
+		a = sum_expr_low (type, '+', a, *s);
 	}
 	for (auto s = subs; *s; s++) {
-		b = sum_expr (type, b, neg_expr (*s));
+		b = sum_expr_low (type, '+', b, *s);
 	}
-	return b;
+	auto sum = sum_expr_low (type, '-', a, b);
+	return sum;
+}
+
+static expr_t *
+sum_expr (type_t *type, expr_t *a, expr_t *b)
+{
+	if (!a) {
+		return b;
+	}
+	if (!b) {
+		return a;
+	}
+
+	auto sum = new_binary_expr ('+', a, b);
+	int num_terms = count_terms (sum);
+	expr_t *adds[num_terms + 1] = {};
+	expr_t *subs[num_terms + 1] = {};
+	distribute_terms (sum, adds, subs);
+	expr_t **dstadd, **srcadd;
+	expr_t **dstsub, **srcsub;
+
+	for (dstadd = adds, srcadd = adds; *srcadd; srcadd++) {
+		for (dstsub = subs, srcsub = subs; *srcsub; srcsub++) {
+			if (*srcadd == *srcsub) {
+				// found a-a
+				break;
+			}
+		}
+		if (*srcsub++) {
+			// found a-a
+			while (*srcsub) {
+				*dstsub++ = *srcsub++;
+			}
+			*dstsub = 0;
+			continue;
+		}
+		*dstadd++ = *srcadd;
+	}
+	*dstadd = 0;
+	sum = collect_terms (type, adds, subs);
+	return sum;
 }
 
 static void
@@ -564,7 +556,9 @@ component_sum (int op, expr_t **c, expr_t **a, expr_t **b,
 			} else {
 				c[i] = sum_expr (sum_type, a[i], neg_expr (b[i]));
 			}
-			c[i] = fold_constants (c[i]);
+			if (c[i]) {
+				c[i] = fold_constants (c[i]);
+			}
 		} else if (a[i]) {
 			c[i] = a[i];
 		} else if (b[i]) {
diff --git a/tools/qfcc/test/pga3d.r b/tools/qfcc/test/pga3d.r
index e787ae7d4..7efe2cecf 100644
--- a/tools/qfcc/test/pga3d.r
+++ b/tools/qfcc/test/pga3d.r
@@ -347,7 +347,7 @@ test_geom (void)
 
 	d = { .mvec = tvec * bvec.bvec };
 	if ((vec4)d.vec != '22 -8 4 9' || (vec4)d.tvec != '-30 -85 34 0') {
-		printf ("vec * bvec != '22 -8 4 9' '-30 -85 34 0': %q %q\n",
+		printf ("tvec * bvec != '22 -8 4 9' '-30 -85 34 0': %q %q\n",
 				d.vec, d.tvec);
 		return 1;
 	}