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

1 files changed, 7 insertions, 0 deletions

diff --git a/compiler/optimizing/code_generator.h b/compiler/optimizing/code_generator.h
index 55f5d8df5f..b58f3b3efc 100644
--- a/compiler/optimizing/code_generator.h
+++ b/compiler/optimizing/code_generator.h
@@ -143,6 +143,13 @@ class CodeGenerator : public ArenaObject {
     is_leaf_ = false;
   }
 
+  // Clears the spill slots taken by loop phis in the `LocationSummary` of the
+  // suspend check. This is called when the code generator generates code
+  // for the suspend check at the back edge (instead of where the suspend check
+  // is, which is the loop entry). At this point, the spill slots for the phis
+  // have not been written to.
+  void ClearSpillSlotsFromLoopPhisInStackMap(HSuspendCheck* suspend_check) const;
+
  protected:
   CodeGenerator(HGraph* graph, size_t number_of_registers)
       : frame_size_(kUninitializedFrameSize),