harec

commit 74650bc728a53268192bc9794c5ac9a78da12215
parent 15d37ce99f3d0f0822b3bb69c1cbcf1c4b4a42a6
Author: Drew DeVault <sir@cmpwn.com>
Date:   Tue,  2 Feb 2021 11:49:26 -0500

check: lower casts to tagged intermediates

Diffstat:
M
src/check.c
 | 
9
+++++++++
M
src/gen.c
 | 
7
++++---

2 files changed, 13 insertions(+), 3 deletions(-)
diff --git a/src/check.c b/src/check.c
@@ -45,6 +45,15 @@ lower_implicit_cast(const struct type *to, struct expression *expr)
 	if (to == expr->result) {
 		return expr;
 	}
+
+	if (type_dealias(to)->storage == TYPE_STORAGE_TAGGED) {
+		const struct type *interim =
+			tagged_select_subtype(to, expr->result);
+		if (interim) {
+			expr = lower_implicit_cast(interim, expr);
+		}
+	}
+
 	struct expression *cast = xcalloc(1, sizeof(struct expression));
 	cast->type = EXPR_CAST;
 	cast->result = to;
diff --git a/src/gen.c b/src/gen.c
@@ -881,19 +881,20 @@ gen_cast_to_tagged(struct gen_context *ctx,
 	const struct type *subtype = tagged_select_subtype(tagged, from);
 
 	struct qbe_value tag = {0}, ptr = {0}, offs = {0};
-	gen_temp(ctx, &ptr, &qbe_long, "to_tagged.from.%d");
 	constl(&offs, expr->result->align);
 
 	if (!subtype) {
 		pushc(ctx->current, "to_tagged; no subtype");
+		alloc_temp(ctx, &ptr, tagged, "to_tagged.from.%d");
+		qval_deref(&ptr);
 		gen_expression(ctx, expr->cast.value, &ptr);
 		gen_copy(ctx, out, &ptr);
 		return;
 	}
 
+	gen_temp(ctx, &ptr, &qbe_long, "to_tagged.from.%d");
 	pushc(ctx->current, "to_tagged; valid subtype");
-	// TODO: check should lower this to multiple casts:
-	assert(subtype->id == from->id);
+	assert(subtype->id == from->id); // Lowered by check
 
 	if (out) {
 		constw(&tag, subtype->id);