[Openmp-commits] [openmp] 99d67fb - [OpenMP] Align up the size when calling aligned_alloc (#65525)

[via Openmp-commits]

Author: Shilei Tian
Date: 2023-09-06T16:28:07-04:00
New Revision: 99d67fb9aad6382c41fffdedc4d4dbadd20d5da4

URL: https://github.com/llvm/llvm-project/commit/99d67fb9aad6382c41fffdedc4d4dbadd20d5da4
DIFF: https://github.com/llvm/llvm-project/commit/99d67fb9aad6382c41fffdedc4d4dbadd20d5da4.diff

LOG: [OpenMP] Align up the size when calling aligned_alloc (#65525)

Based on https://en.cppreference.com/w/c/memory/aligned_alloc, the
`size` is supposed
to be a multiple of `alignment`, and it is implementation defined
behavior if not.
We have a non-conformant use in `kmp_barrier.h` when allocating
distribute barrier.
The size of the barrier is 576 and the alignment is `4*CACHE_LINE`,
which is 256
on most systems. Apparently it works perfectly fine for Linux and
Intel-based Mac,
but not for Apple Silicon based Mac.

Fix #63194.

Added: 
    

Modified: 
    openmp/runtime/src/kmp_barrier.h

Removed: 
    


################################################################################
diff  --git a/openmp/runtime/src/kmp_barrier.h b/openmp/runtime/src/kmp_barrier.h
index ac28a13217e9b4..ae9b8d62f4c3dc 100644
--- a/openmp/runtime/src/kmp_barrier.h
+++ b/openmp/runtime/src/kmp_barrier.h
@@ -21,7 +21,10 @@
 #define KMP_ALIGNED_ALLOCATE(size, alignment) _mm_malloc(size, alignment)
 #define KMP_ALIGNED_FREE(ptr) _mm_free(ptr)
 #elif KMP_HAVE_ALIGNED_ALLOC
-#define KMP_ALIGNED_ALLOCATE(size, alignment) aligned_alloc(alignment, size)
+#define KMP_ALGIN_UP(val, alignment)                                           \
+  (((val) + (alignment)-1) / (alignment) * (alignment))
+#define KMP_ALIGNED_ALLOCATE(size, alignment)                                  \
+  aligned_alloc(alignment, KMP_ALGIN_UP(size, alignment))
 #define KMP_ALIGNED_FREE(ptr) free(ptr)
 #elif KMP_HAVE_POSIX_MEMALIGN
 static inline void *KMP_ALIGNED_ALLOCATE(size_t size, size_t alignment) {