commit 8e3964b766652a0478e8e0e303e8556c997675f1
author Nicolas Geoffray <ngeoffray@google.com> Fri Oct 17 11:06:38 2014 +0100
committer Nicolas Geoffray <ngeoffray@google.com> Tue Oct 21 11:47:54 2014 +0100
tree ebae22017d3d3c872642cbc56610f67ff32a861d
parent 5830247c351a1c40f37666584d6c390f32c31957

Remove the notion of dies at entry.

- Instead, explicitly say that the output does not overlap.
- Inputs that must be in a fixed register do die at entry,
  as we know they have a location that others can not take.
- There is also no need to differentiate between an input move
  and a connecting sibling move - those can be put in the
  same parallel move instruction.

Change-Id: I1b2b2827906601f822b59fb9d6a21d48e43bae27

compiler/optimizing/locations.h

diff --git a/compiler/optimizing/locations.h b/compiler/optimizing/locations.h
index dcf70f2..11bcd78 100644
--- a/compiler/optimizing/locations.h
+++ b/compiler/optimizing/locations.h
@@ -34,7 +34,7 @@
  */
 class Location : public ValueObject {
  public:
-  static constexpr bool kDiesAtEntry = true;
+  static constexpr bool kNoOutputOverlap = false;
 
   enum Kind {
     kInvalid = 0,
@@ -373,8 +373,7 @@
 
   LocationSummary(HInstruction* instruction, CallKind call_kind = kNoCall);
 
-  void SetInAt(uint32_t at, Location location, bool dies_at_entry = false) {
-    dies_at_entry_.Put(at, dies_at_entry);
+  void SetInAt(uint32_t at, Location location) {
     inputs_.Put(at, location);
   }
 
@@ -386,7 +385,8 @@
     return inputs_.Size();
   }
 
-  void SetOut(Location location) {
+  void SetOut(Location location, bool overlaps = true) {
+    output_overlaps_ = overlaps;
     output_ = Location(location);
   }
 
@@ -449,23 +449,30 @@
     return &live_registers_;
   }
 
-  bool InputOverlapsWithOutputOrTemp(uint32_t input, bool is_environment) const {
+  bool InputOverlapsWithOutputOrTemp(uint32_t input_index, bool is_environment) const {
     if (is_environment) return true;
-    Location location = Out();
-    if (input == 0 && location.IsUnallocated() && location.GetPolicy() == Location::kSameAsFirstInput) {
+    if ((input_index == 0)
+        && output_.IsUnallocated()
+        && (output_.GetPolicy() == Location::kSameAsFirstInput)) {
       return false;
     }
-    if (dies_at_entry_.Get(input)) {
+    if (inputs_.Get(input_index).IsRegister() || inputs_.Get(input_index).IsFpuRegister()) {
       return false;
     }
     return true;
   }
 
+  bool OutputOverlapsWithInputs() const {
+    return output_overlaps_;
+  }
+
  private:
   GrowableArray<Location> inputs_;
   GrowableArray<Location> temps_;
   GrowableArray<Location> environment_;
-  GrowableArray<bool> dies_at_entry_;
+  // Whether the output overlaps with any of the inputs. If it overlaps, then it cannot
+  // share the same register as the inputs.
+  bool output_overlaps_;
   Location output_;
   const CallKind call_kind_;