Index: vendor/compiler-rt/dist/test/sanitizer_common/TestCases/Linux/sem_init_glibc.cc
===================================================================
--- vendor/compiler-rt/dist/test/sanitizer_common/TestCases/Linux/sem_init_glibc.cc	(revision 309430)
+++ vendor/compiler-rt/dist/test/sanitizer_common/TestCases/Linux/sem_init_glibc.cc	(revision 309431)
@@ -1,43 +1,58 @@
 // RUN: %clangxx -O0 -g %s -lutil -o %t && %run %t
 // This test depends on the glibc layout of struct sem_t and checks that we
 // don't leave sem_t::private uninitialized.
 // UNSUPPORTED: android
 #include <features.h>
 #include <assert.h>
 #include <semaphore.h>
 #include <string.h>
 #include <stdint.h>
 
 // This condition needs to correspond to __HAVE_64B_ATOMICS macro in glibc.
 #if (defined(__x86_64__) || defined(__aarch64__) || defined(__powerpc64__) || \
      defined(__s390x__) || defined(__sparc64__) || defined(__alpha__) || \
      defined(__ia64__) || defined(__m68k__)) && __GLIBC_PREREQ(2, 21)
 typedef uint64_t semval_t;
 #else
 typedef unsigned semval_t;
 #endif
 
+// glibc 2.21 has introduced some changes in the way the semaphore value is
+// handled for 32-bit platforms, but since these changes are not ABI-breaking
+// they are not versioned. On newer platforms such as ARM, there is only one
+// version of the symbol, so it's enough to check the glibc version. However,
+// for old platforms such as i386, glibc contains two or even three versions of
+// the sem_init symbol, and the sanitizers always pick the oldest one.
+// Therefore, it is not enough to rely on the __GLIBC_PREREQ macro - we should
+// instead check the platform as well to make sure we only expect the new
+// behavior on platforms where the older symbols do not exist.
+#if defined(__arm__) && __GLIBC_PREREQ(2, 21)
+#define GET_SEM_VALUE(V) ((V) >> 1)
+#else
+#define GET_SEM_VALUE(V) (V)
+#endif
+
 void my_sem_init(bool priv, int value, semval_t *a, unsigned char *b) {
   sem_t sem;
   memset(&sem, 0xAB, sizeof(sem));
   sem_init(&sem, priv, value);
 
   char *p = (char *)&sem;
   memcpy(a, p, sizeof(semval_t));
   memcpy(b, p + sizeof(semval_t), sizeof(char));
 
   sem_destroy(&sem);
 }
 
 int main() {
   semval_t a;
   unsigned char b;
 
   my_sem_init(false, 42, &a, &b);
-  assert(a == 42);
+  assert(GET_SEM_VALUE(a) == 42);
   assert(b != 0xAB);
 
   my_sem_init(true, 43, &a, &b);
-  assert(a == 43);
+  assert(GET_SEM_VALUE(a) == 43);
   assert(b != 0xAB);
 }