Merge "Adjust safepoint position of implicit null checks."

1 files changed, 15 insertions, 2 deletions

diff --git a/compiler/optimizing/ssa_liveness_analysis.h b/compiler/optimizing/ssa_liveness_analysis.h
index 97c00c9c1d..92d0b08301 100644
--- a/compiler/optimizing/ssa_liveness_analysis.h
+++ b/compiler/optimizing/ssa_liveness_analysis.h
@@ -230,12 +230,25 @@ class SafepointPosition : public ArenaObject<kArenaAllocSsaLiveness> {
       : instruction_(instruction),
         next_(nullptr) {}
 
+  static size_t ComputePosition(HInstruction* instruction) {
+    // We special case instructions emitted at use site, as their
+    // safepoint position needs to be at their use.
+    if (instruction->IsEmittedAtUseSite()) {
+      // Currently only applies to implicit null checks, which are emitted
+      // at the next instruction.
+      DCHECK(instruction->IsNullCheck()) << instruction->DebugName();
+      return instruction->GetLifetimePosition() + 2;
+    } else {
+      return instruction->GetLifetimePosition();
+    }
+  }
+
   void SetNext(SafepointPosition* next) {
     next_ = next;
   }
 
   size_t GetPosition() const {
-    return instruction_->GetLifetimePosition();
+    return ComputePosition(instruction_);
   }
 
   SafepointPosition* GetNext() const {
@@ -922,7 +935,7 @@ class LiveInterval : public ArenaObject<kArenaAllocSsaLiveness> {
     if (first_safepoint_ == nullptr) {
       first_safepoint_ = last_safepoint_ = safepoint;
     } else {
-      DCHECK_LT(last_safepoint_->GetPosition(), safepoint->GetPosition());
+      DCHECK_LE(last_safepoint_->GetPosition(), safepoint->GetPosition());
       last_safepoint_->SetNext(safepoint);
       last_safepoint_ = safepoint;
     }