The branch main has been updated by dim:
URL:
https://cgit.FreeBSD.org/src/commit/?id=4e5d32a445f90d37966cd6de571978551654e3f3
commit 4e5d32a445f90d37966cd6de571978551654e3f3
Author: Dimitry Andric <d...@freebsd.org>
AuthorDate: 2021-08-27 17:45:43 +0000
Commit: Dimitry Andric <d...@freebsd.org>
CommitDate: 2021-08-27 17:46:18 +0000
Fix null pointer subtraction in mergesort()
Clang 13 produces the following warning for this function:
lib/libc/stdlib/merge.c:137:41: error: performing pointer subtraction with
a null pointer has undefined behavior [-Werror,-Wnull-pointer-subtraction]
if (!(size % ISIZE) && !(((char *)base - (char *)0) % ISIZE))
^ ~~~~~~~~~
This is meant to check whether the size and base parameters are aligned
to the size of an int, so use our __is_aligned() macro instead.
Also remove the comment that indicated this "stupid subtraction" was
done to pacify some ancient and unknown Cray compiler, and which has
been there since the BSD 4.4 Lite Lib Sources were imported.
MFC after: 3 days
---
lib/libc/stdlib/merge.c | 6 +-----
1 file changed, 1 insertion(+), 5 deletions(-)
diff --git a/lib/libc/stdlib/merge.c b/lib/libc/stdlib/merge.c
index 853d6ae93fcb..7d8484ed10b9 100644
--- a/lib/libc/stdlib/merge.c
+++ b/lib/libc/stdlib/merge.c
@@ -129,12 +129,8 @@ mergesort(void *base, size_t nmemb, size_t size, cmp_t cmp)
if (nmemb == 0)
return (0);
- /*
- * XXX
- * Stupid subtraction for the Cray.
- */
iflag = 0;
- if (!(size % ISIZE) && !(((char *)base - (char *)0) % ISIZE))
+ if (__is_aligned(size, ISIZE) && __is_aligned(base, ISIZE))
iflag = 1;
if ((list2 = malloc(nmemb * size + PSIZE)) == NULL)
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