Improved side effect analysis (field/array write/read).

Rationale:
Types (int, float etc.) and access type (field vs. array)
can be used to disambiguate write/read side-effects analysis.
This directly improves e.g. dead code elimination and licm.

Change-Id: I371f6909a3f42bda13190a03f04c4a867bde1d06

1 files changed, 6 insertions, 3 deletions

diff --git a/compiler/optimizing/side_effects_analysis.cc b/compiler/optimizing/side_effects_analysis.cc
index ea1ca5a731..9dbf638442 100644
--- a/compiler/optimizing/side_effects_analysis.cc
+++ b/compiler/optimizing/side_effects_analysis.cc
@@ -24,14 +24,15 @@ void SideEffectsAnalysis::Run() {
   block_effects_.SetSize(graph_->GetBlocks().Size());
   loop_effects_.SetSize(graph_->GetBlocks().Size());
 
+  // In DEBUG mode, ensure side effects are properly initialized to empty.
   if (kIsDebugBuild) {
     for (HReversePostOrderIterator it(*graph_); !it.Done(); it.Advance()) {
       HBasicBlock* block = it.Current();
       SideEffects effects = GetBlockEffects(block);
-      DCHECK(!effects.HasSideEffects() && !effects.HasDependencies());
+      DCHECK(effects.DoesNothing());
       if (block->IsLoopHeader()) {
         effects = GetLoopEffects(block);
-        DCHECK(!effects.HasSideEffects() && !effects.HasDependencies());
+        DCHECK(effects.DoesNothing());
       }
     }
   }
@@ -46,7 +47,9 @@ void SideEffectsAnalysis::Run() {
          inst_it.Advance()) {
       HInstruction* instruction = inst_it.Current();
       effects = effects.Union(instruction->GetSideEffects());
-      if (effects.HasAllSideEffects()) {
+      // If every possible write/read is represented, scanning further
+      // will not add any more information to side-effects of this block.
+      if (effects.DoesAll()) {
         break;
       }
     }