Do a null check on the sibling in the register allocator.

There may be a lifetime hole between the intervals, which means there is
no interval for the given position.

Litle sister of https://android-review.googlesource.com/#/c/209336/.

bug:27626705
Change-Id: I8082aa5ae2dc37d8fa5d4c430b69e6defa495439

1 files changed, 1 insertions, 1 deletions

diff --git a/compiler/optimizing/register_allocator.cc b/compiler/optimizing/register_allocator.cc
index 44bede8ac0..b1f9cbcdfa 100644
--- a/compiler/optimizing/register_allocator.cc
+++ b/compiler/optimizing/register_allocator.cc
@@ -1931,7 +1931,7 @@ void RegisterAllocator::Resolve() {
           // `GetSiblingAt` returns the sibling that contains a position, but there could be
           // a lifetime hole in it. `CoversSlow` returns whether the interval is live at that
           // position.
-          if (sibling->CoversSlow(block->GetLifetimeStart())) {
+          if ((sibling != nullptr) && sibling->CoversSlow(block->GetLifetimeStart())) {
             DCHECK(!sibling->HasRegister());
           }
         }