Optimize suspend checks in optimizing compiler.

- Remove the ones added during graph build (they were added
  for the baseline code generator).
- Emit them at loop back edges after phi moves, so that the test
  can directly jump to the loop header.
- Fix x86 and x86_64 suspend check by using cmpw instead of cmpl.

Change-Id: I6fad5795a55705d86c9e1cb85bf5d63dadfafa2a
diff --git a/compiler/optimizing/builder.cc b/compiler/optimizing/builder.cc
index 33b00d2..5015bd0 100644
--- a/compiler/optimizing/builder.cc
+++ b/compiler/optimizing/builder.cc
@@ -183,9 +183,9 @@
 
   // Setup the graph with the entry block and exit block.
   graph_ = new (arena_) HGraph(arena_);
-  entry_block_ = new (arena_) HBasicBlock(graph_);
+  entry_block_ = new (arena_) HBasicBlock(graph_, 0);
   graph_->AddBlock(entry_block_);
-  exit_block_ = new (arena_) HBasicBlock(graph_);
+  exit_block_ = new (arena_) HBasicBlock(graph_, kNoDexPc);
   graph_->SetEntryBlock(entry_block_);
   graph_->SetExitBlock(exit_block_);
 
@@ -241,7 +241,7 @@
   branch_targets_.SetSize(code_end - code_ptr);
 
   // Create the first block for the dex instructions, single successor of the entry block.
-  HBasicBlock* block = new (arena_) HBasicBlock(graph_);
+  HBasicBlock* block = new (arena_) HBasicBlock(graph_, 0);
   branch_targets_.Put(0, block);
   entry_block_->AddSuccessor(block);
 
@@ -254,13 +254,13 @@
       int32_t target = instruction.GetTargetOffset() + dex_offset;
       // Create a block for the target instruction.
       if (FindBlockStartingAt(target) == nullptr) {
-        block = new (arena_) HBasicBlock(graph_);
+        block = new (arena_) HBasicBlock(graph_, target);
         branch_targets_.Put(target, block);
       }
       dex_offset += instruction.SizeInCodeUnits();
       code_ptr += instruction.SizeInCodeUnits();
       if ((code_ptr < code_end) && (FindBlockStartingAt(dex_offset) == nullptr)) {
-        block = new (arena_) HBasicBlock(graph_);
+        block = new (arena_) HBasicBlock(graph_, dex_offset);
         branch_targets_.Put(dex_offset, block);
       }
     } else {