Step-wise improvement of range analysis with outer loop induction.

Rationale: Using a step-wise approach (rather than expanding all ranges
           at once) increases the opportunities for statically removing
           bound checks, as demonstrated by the new checker tests.

Change-Id: Icbfd9406523a069e1fb7508546ea94f896e5a255

1 files changed, 9 insertions, 0 deletions

diff --git a/compiler/optimizing/induction_var_range.h b/compiler/optimizing/induction_var_range.h
index 7984871b08..71b0b1b4c3 100644
--- a/compiler/optimizing/induction_var_range.h
+++ b/compiler/optimizing/induction_var_range.h
@@ -68,6 +68,9 @@ class InductionVarRange {
                          /*out*/Value* max_val,
                          /*out*/bool* needs_finite_test);
 
+  /** Refines the values with induction of next outer loop. Returns true on change. */
+  bool RefineOuter(/*in-out*/Value* min_val, /*in-out*/Value* max_val);
+
   /**
    * Returns true if range analysis is able to generate code for the lower and upper
    * bound expressions on the instruction in the given context. The need_finite_test
@@ -149,6 +152,12 @@ class InductionVarRange {
   static Value MergeVal(Value v1, Value v2, bool is_min);
 
   /**
+   * Returns refined value using induction of next outer loop or the input value if no
+   * further refinement is possible.
+   */
+  Value RefineOuter(Value val, bool is_min);
+
+  /**
    * Generates code for lower/upper/taken-test in the HIR. Returns true on success.
    * With values nullptr, the method can be used to determine if code generation
    * would be successful without generating actual code yet.