[OpenMP] libomp: fix alignment issue in dist barrier on non-x86

[t-msn]

Summary

Following tsan warning appears on arm64 when using dist barrier:

1: ==603732==ERROR: ThreadSanitizer: invalid alignment requested in aligned_alloc: 1024,\
alignment must be a power of two and the requested size 0x900 must be a multiple of alignment

As the message says, roundup the size to be passed in alinged_alloc to fix this.

[t-msn]

I noticed this when running check-openmp with dist barrier by using https://reviews.llvm.org/D122645

[tlwilmar]

Just a side note that dist barrier is an Intel-hardware-specific barrier. It's not likely to work well for non-Intel hardware.

openmp/runtime/src/kmp_barrier.h

 #include "kmp.h"
 #include "kmp_i18n.h"
 
 #if KMP_HAVE_XMMINTRIN_H && KMP_HAVE__MM_MALLOC
 #include <xmmintrin.h>
 #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)
+static inline size_t roundup(size_t val, size_t to) {
+  return (val + to - 1) / to * to;
+}
+#define KMP_ALIGNED_ALLOCATE(size, alignment)                                  \
+  aligned_alloc(alignment, roundup(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) {
   void *ptr;
   int n = posix_memalign(&ptr, alignment, size);
   if (n != 0) {
     if (ptr)
       free(ptr);