ART: Update last_instruction when adding Phis

HBasicBlock::InsertPhiAfter would not update the last_instruction
pointer when adding at the end of the list. This could cause problems
when iterating over phis backwards. Fortunately, we don't do that
anywhere in the existing code.

Change-Id: I4487265bf2cf3d3819623fafd7ce7c359bac190e

1 files changed, 19 insertions, 6 deletions

diff --git a/compiler/optimizing/graph_checker.cc b/compiler/optimizing/graph_checker.cc
index e743d8eca8..8950635d6a 100644
--- a/compiler/optimizing/graph_checker.cc
+++ b/compiler/optimizing/graph_checker.cc
@@ -88,23 +88,36 @@ void GraphChecker::VisitBasicBlock(HBasicBlock* block) {
 
   // Visit this block's list of phis.
   for (HInstructionIterator it(block->GetPhis()); !it.Done(); it.Advance()) {
+    HInstruction* current = it.Current();
     // Ensure this block's list of phis contains only phis.
-    if (!it.Current()->IsPhi()) {
+    if (!current->IsPhi()) {
       AddError(StringPrintf("Block %d has a non-phi in its phi list.",
                             current_block_->GetBlockId()));
     }
-    it.Current()->Accept(this);
+    if (current->GetNext() == nullptr && current != block->GetLastPhi()) {
+      AddError(StringPrintf("The recorded last phi of block %d does not match "
+                            "the actual last phi %d.",
+                            current_block_->GetBlockId(),
+                            current->GetId()));
+    }
+    current->Accept(this);
   }
 
   // Visit this block's list of instructions.
-  for (HInstructionIterator it(block->GetInstructions()); !it.Done();
-       it.Advance()) {
+  for (HInstructionIterator it(block->GetInstructions()); !it.Done(); it.Advance()) {
+    HInstruction* current = it.Current();
     // Ensure this block's list of instructions does not contains phis.
-    if (it.Current()->IsPhi()) {
+    if (current->IsPhi()) {
       AddError(StringPrintf("Block %d has a phi in its non-phi list.",
                             current_block_->GetBlockId()));
     }
-    it.Current()->Accept(this);
+    if (current->GetNext() == nullptr && current != block->GetLastInstruction()) {
+      AddError(StringPrintf("The recorded last instruction of block %d does not match "
+                            "the actual last instruction %d.",
+                            current_block_->GetBlockId(),
+                            current->GetId()));
+    }
+    current->Accept(this);
   }
 }