Improved induction variable analysis and loop optimizations.

Rationale:
Rather than half-baked reconstructing cycles during loop optimizations,
this CL passes the SCC computed during induction variable analysis
to the loop optimizer (trading some memory for more optimizations).
This further improves CaffeineLogic from 6000us down to 4200us (dx)
and 2200us to 1690us (jack). Note that this is on top of prior
improvements in previous CLs. Also, some narrowing type concerns
are taken care of during transfer operations.

Test: test-art-host
Change-Id: Ice2764811a70073c5014b3a05fb51f39fd2f4c3c

1 files changed, 7 insertions, 0 deletions

diff --git a/compiler/optimizing/induction_var_analysis.h b/compiler/optimizing/induction_var_analysis.h
index d19078248c..70271799d2 100644
--- a/compiler/optimizing/induction_var_analysis.h
+++ b/compiler/optimizing/induction_var_analysis.h
@@ -214,6 +214,8 @@ class HInductionVarAnalysis : public HOptimization {
   InductionInfo* LookupInfo(HLoopInformation* loop, HInstruction* instruction);
   InductionInfo* CreateConstant(int64_t value, Primitive::Type type);
   InductionInfo* CreateSimplifiedInvariant(InductionOp op, InductionInfo* a, InductionInfo* b);
+  void AssignCycle(HPhi* phi);
+  ArenaSet<HInstruction*>* LookupCycle(HPhi* phi);
 
   // Constants.
   bool IsExact(InductionInfo* info, /*out*/ int64_t* value);
@@ -240,6 +242,11 @@ class HInductionVarAnalysis : public HOptimization {
    */
   ArenaSafeMap<HLoopInformation*, ArenaSafeMap<HInstruction*, InductionInfo*>> induction_;
 
+  /**
+   * Preserves induction cycle information for each loop-phi.
+   */
+  ArenaSafeMap<HPhi*, ArenaSet<HInstruction*>> cycles_;
+
   friend class InductionVarAnalysisTest;
   friend class InductionVarRange;
   friend class InductionVarRangeTest;