chieftec$ uname -a
NetBSD chieftec 8.99.6 NetBSD 8.99.6 (GENERIC) #7: Thu Nov  9 20:58:03 CET 2017  root@chieftec:/public/netbsd-root/sys/arch/amd64/compile/GENERIC amd64

chieftec$ date
czw. lis 16 02:18:10 CET 2017

chieftec$ ./bin/clang++ umr.cc -o umr -fsanitize=memory -g -O0
chieftec$ ./umr

MemorySanitizer:DEADLYSIGNAL
==26322==ERROR: MemorySanitizer: SEGV on unknown address 0x103000000014
(pc 0x00000044e293 bp 0x7f7fffffe7b0 sp 0x7f7fffffe710 T1)
==26322==The signal is caused by a WRITE memory access.
    #0 0x44e292 in main /public/llvm-build/umr.cc:5:8
    #1 0x442ab6 in ReportDeadlySignalImpl
/public/llvm/projects/compiler-rt/lib/sanitizer_common/sanitizer_common_libcdep.cc:241:3
    #2 0x442ab6 in
__sanitizer::ReportDeadlySignal(__sanitizer::SignalContext const&,
unsigned int, void (*)(__sanitizer::SignalContext const&, void const*,
__sanitizer::BufferedStackTrace*), void const*)
/public/llvm/projects/compiler-rt/lib/sanitizer_common/sanitizer_common_libcdep.cc:255
    #3 0x442de8 in __sanitizer::HandleDeadlySignal(void*, void*,
unsigned int, void (*)(__sanitizer::SignalContext const&, void const*,
__sanitizer::BufferedStackTrace*), void const*)
/public/llvm/projects/compiler-rt/lib/sanitizer_common/sanitizer_common_libcdep.cc:264:3
    #4 0x7f7ff68a004f in opendir (/usr/lib/libc.so.12+0xa004f)
    #5 0x10000000a  (<unknown module>)

MemorySanitizer can not provide additional info.
SUMMARY: MemorySanitizer: SEGV /public/llvm-build/umr.cc:5:8 in main
==26322==ABORTING
chieftec$ cat umr.cc
#include <stdio.h>

int main(int argc, char** argv) {
  int* a = new int[10];
  a[5] = 0;
  if (a[argc])
    printf("xx\n");
  return 0;
}