Add loop recognition and CFG simplifications in new compiler.

We do three simplifications:
- Split critical edges, for code generation from SSA (new).
- Ensure one back edge per loop, to simplify loop recognition (new).
- Ensure only one pre header for a loop, to simplify SSA creation (existing).

Change-Id: I9bfccd4b236a00486a261078627b091c8a68be33

1 files changed, 9 insertions, 9 deletions

diff --git a/compiler/optimizing/ssa_builder.cc b/compiler/optimizing/ssa_builder.cc
index ee1e1e4..1fc041c 100644
--- a/compiler/optimizing/ssa_builder.cc
+++ b/compiler/optimizing/ssa_builder.cc
@@ -32,8 +32,8 @@ void SsaBuilder::BuildSsa() {
     HBasicBlock* block = loop_headers_.Get(i);
     for (HInstructionIterator it(*block->GetPhis()); !it.Done(); it.Advance()) {
       HPhi* phi = it.Current()->AsPhi();
-      for (size_t pred = 0; pred < block->GetPredecessors()->Size(); pred++) {
-        phi->AddInput(ValueOfLocal(block->GetPredecessors()->Get(pred), phi->GetRegNumber()));
+      for (size_t pred = 0; pred < block->GetPredecessors().Size(); pred++) {
+        phi->AddInput(ValueOfLocal(block->GetPredecessors().Get(pred), phi->GetRegNumber()));
       }
     }
   }
@@ -75,14 +75,14 @@ void SsaBuilder::VisitBasicBlock(HBasicBlock* block) {
     // Save the loop header so that the last phase of the analysis knows which
     // blocks need to be updated.
     loop_headers_.Add(block);
-  } else if (block->GetPredecessors()->Size() > 0) {
+  } else if (block->GetPredecessors().Size() > 0) {
     // All predecessors have already been visited because we are visiting in reverse post order.
     // We merge the values of all locals, creating phis if those values differ.
     for (size_t local = 0; local < current_locals_->Size(); local++) {
       bool is_different = false;
-      HInstruction* value = ValueOfLocal(block->GetPredecessors()->Get(0), local);
-      for (size_t i = 1; i < block->GetPredecessors()->Size(); i++) {
-        if (ValueOfLocal(block->GetPredecessors()->Get(i), local) != value) {
+      HInstruction* value = ValueOfLocal(block->GetPredecessors().Get(0), local);
+      for (size_t i = 1; i < block->GetPredecessors().Size(); i++) {
+        if (ValueOfLocal(block->GetPredecessors().Get(i), local) != value) {
           is_different = true;
           break;
         }
@@ -90,9 +90,9 @@ void SsaBuilder::VisitBasicBlock(HBasicBlock* block) {
       if (is_different) {
         // TODO: Compute union type.
         HPhi* phi = new (GetGraph()->GetArena()) HPhi(
-            GetGraph()->GetArena(), local, block->GetPredecessors()->Size(), Primitive::kPrimVoid);
-        for (size_t i = 0; i < block->GetPredecessors()->Size(); i++) {
-          phi->SetRawInputAt(i, ValueOfLocal(block->GetPredecessors()->Get(i), local));
+            GetGraph()->GetArena(), local, block->GetPredecessors().Size(), Primitive::kPrimVoid);
+        for (size_t i = 0; i < block->GetPredecessors().Size(); i++) {
+          phi->SetRawInputAt(i, ValueOfLocal(block->GetPredecessors().Get(i), local));
         }
         block->AddPhi(phi);
         value = phi;