harec

commit 9c2ad2b58a6cdb6012fb559a90a45c681390e85a
parent 727c5de862700a15dabb3863167bbbf6ddecadd7
Author: Drew DeVault <sir@cmpwn.com>
Date:   Sat, 13 Feb 2021 11:32:43 -0500

gen: more casts between alignment-distinct taggeds

Diffstat:
M
src/gen.c
 | 
30
+++++++++++++++++++++++++++++-
M
tests/18-match.ha
 | 
3
+++

2 files changed, 32 insertions(+), 1 deletion(-)
diff --git a/src/gen.c b/src/gen.c
@@ -1085,7 +1085,35 @@ gen_cast_to_tagged(struct gen_context *ctx,
 	struct qbe_value tag = {0}, ptr = {0}, offs = {0};
 	constl(&offs, expr->result->align);
 
-	if (!subtype) {
+	if (!subtype && type_dealias(from)->storage == TYPE_STORAGE_TAGGED
+			&& from->align != tagged->align
+			&& type_dealias(tagged)->size != builtin_type_uint.size
+			&& type_dealias(from)->size != builtin_type_uint.size) {
+		// If the alignment differs, we can't use a straight-up copy
+		struct qbe_value src = {0}, dest = {0};
+		pushc(ctx->current, "to_tagged; converting incompatible");
+		alloc_temp(ctx, &src, from, "to_tagged.from.%d");
+		qval_deref(&src);
+		gen_expression(ctx, expr->cast.value, &src);
+
+		gen_temp(ctx, &dest,
+			qtype_for_type(ctx, tagged, false), "to_tagged.to.%d");
+		pushi(ctx->current, &dest, Q_COPY, out, NULL);
+
+		gen_temp(ctx, &tag, &qbe_word, "to_tagged.tag.%d");
+		pushi(ctx->current, &tag, Q_LOADUW, &src, NULL);
+		pushi(ctx->current, NULL, Q_STOREW, &tag, &dest, NULL);
+
+		constl(&offs, tagged->align);
+		pushi(ctx->current, &dest, Q_ADD, &dest, &offs, NULL);
+		constl(&offs, from->align);
+		pushi(ctx->current, &src, Q_ADD, &src, &offs, NULL);
+
+		dest.type = dest.type->fields.next->type;
+		src.type = src.type->fields.next->type;
+		gen_copy(ctx, &dest, &src);
+		return;
+	} else if (!subtype) {
 		pushc(ctx->current, "to_tagged; no subtype");
 		alloc_temp(ctx, &ptr, tagged, "to_tagged.from.%d");
 		qval_deref(&ptr);
diff --git a/tests/18-match.ha b/tests/18-match.ha
@@ -190,6 +190,9 @@ export fn alignment_conversion() void = {
 		y: align_4 => assert(y as int == 1234),
 		* => abort(),
 	};
+	let y: align_4 = 4321i;
+	x = y: align_8;
+	assert(x as int == 4321);
 };
 
 export fn main() void = {