diff options
Diffstat (limited to 'src/alloc.c')
| -rw-r--r-- | src/alloc.c | 8 |
1 files changed, 5 insertions, 3 deletions
diff --git a/src/alloc.c b/src/alloc.c index 28ca7804ee9..abb98a9eb68 100644 --- a/src/alloc.c +++ b/src/alloc.c @@ -641,9 +641,11 @@ buffer_memory_full (ptrdiff_t nbytes) implement Lisp objects; since pseudovectors can contain any C type, this is max_align_t. On recent GNU/Linux x86 and x86-64 this can often waste up to 8 bytes, since alignof (max_align_t) is 16 but - typical vectors need only an alignment of 8. However, it is not - worth the hassle to avoid this waste. */ -enum { LISP_ALIGNMENT = alignof (union { max_align_t x; GCALIGNED_UNION }) }; + typical vectors need only an alignment of 8. Although shrinking + the alignment to 8 would save memory, it cost a 20% hit to Emacs + CPU performance on Fedora 28 x86-64 when compiled with gcc -m32. */ +enum { LISP_ALIGNMENT = alignof (union { max_align_t x; + GCALIGNED_UNION_MEMBER }) }; verify (LISP_ALIGNMENT % GCALIGNMENT == 0); /* True if malloc (N) is known to return storage suitably aligned for |