Use range analysis for better trip count analysis
Rationale:
Marking more loops as always-taken avoids generating
unnecessary new top tests while marking more loops
are non-infinite enables more optimizations. This
CL helps with these improvements. Also, some more
code is shared between induction and range analysis
and a bug with refining ranges has been fixed.
Bug: 27151190
Change-Id: Iecc0d7f32ae4779ee5424cda9dcc20816220935e
diff --git a/compiler/optimizing/induction_var_range.h b/compiler/optimizing/induction_var_range.h
index 3cb7b4b..0af4156 100644
--- a/compiler/optimizing/induction_var_range.h
+++ b/compiler/optimizing/induction_var_range.h
@@ -69,7 +69,8 @@
/*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) const;
+ bool RefineOuter(/*in-out*/ Value* min_val,
+ /*in-out*/ Value* max_val) const;
/**
* Returns true if range analysis is able to generate code for the lower and upper
@@ -116,6 +117,23 @@
/*out*/ HInstruction** taken_test);
private:
+ /*
+ * Enum used in IsConstant() request.
+ */
+ enum ConstantRequest {
+ kExact,
+ kAtMost,
+ kAtLeast
+ };
+
+ /**
+ * Returns true if exact or upper/lower bound on the given induction
+ * information is known as a 64-bit constant, which is returned in value.
+ */
+ bool IsConstant(HInductionVarAnalysis::InductionInfo* info,
+ ConstantRequest request,
+ /*out*/ int64_t *value) const;
+
bool NeedsTripCount(HInductionVarAnalysis::InductionInfo* info) const;
bool IsBodyTripCount(HInductionVarAnalysis::InductionInfo* trip) const;
bool IsUnsafeTripCount(HInductionVarAnalysis::InductionInfo* trip) const;
@@ -143,9 +161,8 @@
bool in_body,
bool is_min) const;
- bool IsConstantRange(HInductionVarAnalysis::InductionInfo* info,
- int32_t *min_value,
- int32_t *max_value) const;
+ Value MulRangeAndConstant(Value v1, Value v2, Value c, bool is_min) const;
+ Value DivRangeAndConstant(Value v1, Value v2, Value c, bool is_min) const;
Value AddValue(Value v1, Value v2) const;
Value SubValue(Value v1, Value v2) const;