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, 20 insertions, 0 deletions

diff --git a/compiler/optimizing/code_generator.cc b/compiler/optimizing/code_generator.cc
index 3231c99a7b..2a9a7b37ab 100644
--- a/compiler/optimizing/code_generator.cc
+++ b/compiler/optimizing/code_generator.cc
@@ -25,6 +25,7 @@
 #include "gc_map_builder.h"
 #include "leb128.h"
 #include "mapping_table.h"
+#include "ssa_liveness_analysis.h"
 #include "utils/assembler.h"
 #include "verifier/dex_gc_map.h"
 #include "vmap_table.h"
@@ -518,4 +519,23 @@ void CodeGenerator::RestoreLiveRegisters(LocationSummary* locations) {
   }
 }
 
+void CodeGenerator::ClearSpillSlotsFromLoopPhisInStackMap(HSuspendCheck* suspend_check) const {
+  LocationSummary* locations = suspend_check->GetLocations();
+  HBasicBlock* block = suspend_check->GetBlock();
+  DCHECK(block->GetLoopInformation()->GetSuspendCheck() == suspend_check);
+  DCHECK(block->IsLoopHeader());
+
+  for (HInstructionIterator it(block->GetPhis()); !it.Done(); it.Advance()) {
+    HInstruction* current = it.Current();
+    LiveInterval* interval = current->GetLiveInterval();
+    // We only need to clear bits of loop phis containing objects and allocated in register.
+    // Loop phis allocated on stack already have the object in the stack.
+    if (current->GetType() == Primitive::kPrimNot
+        && interval->HasRegister()
+        && interval->HasSpillSlot()) {
+      locations->ClearStackBit(interval->GetSpillSlot() / kVRegSize);
+    }
+  }
+}
+
 }  // namespace art