Minor improvement on static BCE analysis.
Rationale:
Avoid testing initial range if nothing is known.
Change-Id: I22646a5fd6e4481245d1a2f57891d2805550489f
diff --git a/compiler/optimizing/bounds_check_elimination.cc b/compiler/optimizing/bounds_check_elimination.cc
index eee6116..c307522 100644
--- a/compiler/optimizing/bounds_check_elimination.cc
+++ b/compiler/optimizing/bounds_check_elimination.cc
@@ -1227,27 +1227,28 @@
InductionVarRange::Value v1;
InductionVarRange::Value v2;
bool needs_finite_test = false;
- induction_range_.GetInductionRange(context, index, &v1, &v2, &needs_finite_test);
- do {
- if (v1.is_known && (v1.a_constant == 0 || v1.a_constant == 1) &&
- v2.is_known && (v2.a_constant == 0 || v2.a_constant == 1)) {
- DCHECK(v1.a_constant == 1 || v1.instruction == nullptr);
- DCHECK(v2.a_constant == 1 || v2.instruction == nullptr);
- ValueRange index_range(GetGraph()->GetArena(),
- ValueBound(v1.instruction, v1.b_constant),
- ValueBound(v2.instruction, v2.b_constant));
- // If analysis reveals a certain OOB, disable dynamic BCE.
- if (index_range.GetLower().LessThan(array_range->GetLower()) ||
- index_range.GetUpper().GreaterThan(array_range->GetUpper())) {
- *try_dynamic_bce = false;
- return false;
+ if (induction_range_.GetInductionRange(context, index, &v1, &v2, &needs_finite_test)) {
+ do {
+ if (v1.is_known && (v1.a_constant == 0 || v1.a_constant == 1) &&
+ v2.is_known && (v2.a_constant == 0 || v2.a_constant == 1)) {
+ DCHECK(v1.a_constant == 1 || v1.instruction == nullptr);
+ DCHECK(v2.a_constant == 1 || v2.instruction == nullptr);
+ ValueRange index_range(GetGraph()->GetArena(),
+ ValueBound(v1.instruction, v1.b_constant),
+ ValueBound(v2.instruction, v2.b_constant));
+ // If analysis reveals a certain OOB, disable dynamic BCE.
+ if (index_range.GetLower().LessThan(array_range->GetLower()) ||
+ index_range.GetUpper().GreaterThan(array_range->GetUpper())) {
+ *try_dynamic_bce = false;
+ return false;
+ }
+ // Use analysis for static bce only if loop is finite.
+ if (!needs_finite_test && index_range.FitsIn(array_range)) {
+ return true;
+ }
}
- // Use analysis for static bce only if loop is finite.
- if (!needs_finite_test && index_range.FitsIn(array_range)) {
- return true;
- }
- }
- } while (induction_range_.RefineOuter(&v1, &v2));
+ } while (induction_range_.RefineOuter(&v1, &v2));
+ }
return false;
}
diff --git a/compiler/optimizing/induction_var_range.cc b/compiler/optimizing/induction_var_range.cc
index ae15fcf..9566c29 100644
--- a/compiler/optimizing/induction_var_range.cc
+++ b/compiler/optimizing/induction_var_range.cc
@@ -93,7 +93,7 @@
DCHECK(induction_analysis != nullptr);
}
-void InductionVarRange::GetInductionRange(HInstruction* context,
+bool InductionVarRange::GetInductionRange(HInstruction* context,
HInstruction* instruction,
/*out*/Value* min_val,
/*out*/Value* max_val,
@@ -111,12 +111,9 @@
*min_val = GetVal(info, trip, in_body, /* is_min */ true);
*max_val = SimplifyMax(GetVal(info, trip, in_body, /* is_min */ false));
*needs_finite_test = NeedsTripCount(info) && IsUnsafeTripCount(trip);
- } else {
- // No loop to analyze.
- *min_val = Value();
- *max_val = Value();
- *needs_finite_test = false;
+ return true;
}
+ return false; // Nothing known
}
bool InductionVarRange::RefineOuter(/*in-out*/Value* min_val, /*in-out*/Value* max_val) const {
diff --git a/compiler/optimizing/induction_var_range.h b/compiler/optimizing/induction_var_range.h
index 974b8fb..3cb7b4b 100644
--- a/compiler/optimizing/induction_var_range.h
+++ b/compiler/optimizing/induction_var_range.h
@@ -60,13 +60,13 @@
* Given a context denoted by the first instruction, returns a possibly conservative
* lower and upper bound on the instruction's value in the output parameters min_val
* and max_val, respectively. The need_finite_test flag denotes if an additional finite-test
- * is needed to protect the range evaluation inside its loop.
+ * is needed to protect the range evaluation inside its loop. Returns false on failure.
*/
- void GetInductionRange(HInstruction* context,
+ bool GetInductionRange(HInstruction* context,
HInstruction* instruction,
- /*out*/Value* min_val,
- /*out*/Value* max_val,
- /*out*/bool* needs_finite_test);
+ /*out*/ Value* min_val,
+ /*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) const;
@@ -79,8 +79,8 @@
*/
bool CanGenerateCode(HInstruction* context,
HInstruction* instruction,
- /*out*/bool* needs_finite_test,
- /*out*/bool* needs_taken_test);
+ /*out*/ bool* needs_finite_test,
+ /*out*/ bool* needs_taken_test);
/**
* Generates the actual code in the HIR for the lower and upper bound expressions on the
@@ -101,8 +101,8 @@
HInstruction* instruction,
HGraph* graph,
HBasicBlock* block,
- /*out*/HInstruction** lower,
- /*out*/HInstruction** upper);
+ /*out*/ HInstruction** lower,
+ /*out*/ HInstruction** upper);
/**
* Generates explicit taken-test for the loop in the given context. Code is generated in
@@ -113,7 +113,7 @@
void GenerateTakenTest(HInstruction* context,
HGraph* graph,
HBasicBlock* block,
- /*out*/HInstruction** taken_test);
+ /*out*/ HInstruction** taken_test);
private:
bool NeedsTripCount(HInductionVarAnalysis::InductionInfo* info) const;
@@ -168,17 +168,17 @@
HInstruction* instruction,
HGraph* graph,
HBasicBlock* block,
- /*out*/HInstruction** lower,
- /*out*/HInstruction** upper,
- /*out*/HInstruction** taken_test,
- /*out*/bool* needs_finite_test,
- /*out*/bool* needs_taken_test) const;
+ /*out*/ HInstruction** lower,
+ /*out*/ HInstruction** upper,
+ /*out*/ HInstruction** taken_test,
+ /*out*/ bool* needs_finite_test,
+ /*out*/ bool* needs_taken_test) const;
bool GenerateCode(HInductionVarAnalysis::InductionInfo* info,
HInductionVarAnalysis::InductionInfo* trip,
HGraph* graph,
HBasicBlock* block,
- /*out*/HInstruction** result,
+ /*out*/ HInstruction** result,
bool in_body,
bool is_min) const;