Linear scan: split at better positions.

- Split at block entry to piggy back on control flow resolution.
- Split at the loop header, if the split position is within a loop.

Change-Id: I718299a58c02ee02a1b22bda589607c69a35f0e8

1 files changed, 11 insertions, 0 deletions

diff --git a/compiler/optimizing/ssa_liveness_analysis.h b/compiler/optimizing/ssa_liveness_analysis.h
index fe70d3a861..97254edb5e 100644
--- a/compiler/optimizing/ssa_liveness_analysis.h
+++ b/compiler/optimizing/ssa_liveness_analysis.h
@@ -998,6 +998,15 @@ class SsaLivenessAnalysis : public ValueObject {
     return instructions_from_lifetime_position_.Get(index);
   }
 
+  HBasicBlock* GetBlockFromPosition(size_t index) const {
+    HInstruction* instruction = GetInstructionFromPosition(index / 2);
+    if (instruction == nullptr) {
+      // If we are at a block boundary, get the block following.
+      instruction = GetInstructionFromPosition((index / 2) + 1);
+    }
+    return instruction->GetBlock();
+  }
+
   HInstruction* GetTempUser(LiveInterval* temp) const {
     // A temporary shares the same lifetime start as the instruction that requires it.
     DCHECK(temp->IsTemp());
@@ -1068,6 +1077,8 @@ class SsaLivenessAnalysis : public ValueObject {
   GrowableArray<HInstruction*> instructions_from_lifetime_position_;
   size_t number_of_ssa_values_;
 
+  ART_FRIEND_TEST(RegisterAllocatorTest, SpillInactive);
+
   DISALLOW_COPY_AND_ASSIGN(SsaLivenessAnalysis);
 };