alloc: Don't require size % align == 0

Allowing unaligned sizes will allow us to allocate aligned slabs with
additional metadata in the tail without ballooning the allocation size
for large alignments.

Link: https://www.open-std.org/jtc1/sc22/wg14/www/docs/n2244.htm#dr_460
Link: https://www.open-std.org/jtc1/sc22/wg14/www/docs/n2072.htm

1 files changed, 8 insertions, 0 deletions

diff --git a/tests/alloc.c b/tests/alloc.c
index f91b428..046613a 100644
--- a/tests/alloc.c
+++ b/tests/alloc.c
@@ -11,6 +11,14 @@
 #include <stdint.h>
 
 void check_alloc(void) {
+	// Check aligned allocation
+	void *ptr;
+	bfs_everify((ptr = zalloc(64, 129)));
+	bfs_check((uintptr_t)ptr % 64 == 0);
+	bfs_echeck((ptr = xrealloc(ptr, 64, 129, 65)));
+	bfs_check((uintptr_t)ptr % 64 == 0);
+	free(ptr);
+
 	// Check sizeof_flex()
 	struct flexible {
 		alignas(64) int foo[8];