From f2ddac4cbc895837ddcc55015fae112f9859cd0a Mon Sep 17 00:00:00 2001 From: Michael Biebl Date: Tue, 20 Oct 2020 22:07:24 +0200 Subject: New upstream version 1.27.91 --- shared/c-rbtree/src/c-rbtree.c | 14 ++++++++------ 1 file changed, 8 insertions(+), 6 deletions(-) (limited to 'shared/c-rbtree/src/c-rbtree.c') diff --git a/shared/c-rbtree/src/c-rbtree.c b/shared/c-rbtree/src/c-rbtree.c index aacdcc29..2f0e608f 100644 --- a/shared/c-rbtree/src/c-rbtree.c +++ b/shared/c-rbtree/src/c-rbtree.c @@ -31,15 +31,17 @@ #include "c-rbtree-private.h" /* - * We use alignas(8) to enforce 64bit alignment of structure fields. This is - * according to ISO-C11, so we rely on the compiler to implement this. However, - * at the same time we don't want to exceed native malloc() alignment on target - * platforms. Hence, we also verify against max_align_t. + * We use the lower 2 bits of CRBNode pointers to store flags. Make sure + * CRBNode is 4-byte aligned, so the lower 2 bits are actually unused. We also + * sometimes store a pointer to the root-node, so make sure this one is also 4 + * byte aligned. + * Note that there are actually some architectures where `max_align_t` is 4, so + * we do not have much wiggle-room to extend this flag-set. */ static_assert(alignof(CRBNode) <= alignof(max_align_t), "Invalid RBNode alignment"); -static_assert(alignof(CRBNode) >= 8, "Invalid CRBNode alignment"); +static_assert(alignof(CRBNode) >= 4, "Invalid CRBNode alignment"); static_assert(alignof(CRBTree) <= alignof(max_align_t), "Invalid RBTree alignment"); -static_assert(alignof(CRBTree) >= 8, "Invalid CRBTree alignment"); +static_assert(alignof(CRBTree) >= 4, "Invalid CRBTree alignment"); /** * c_rbnode_leftmost() - return leftmost child -- cgit 1.3.0-6-gf8a5