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
diff --git a/compiler/optimizing/induction_var_range.cc b/compiler/optimizing/induction_var_range.cc
index 2ac1e15..9d0cde7 100644
--- a/compiler/optimizing/induction_var_range.cc
+++ b/compiler/optimizing/induction_var_range.cc
@@ -119,6 +119,17 @@
}
}
+bool InductionVarRange::RefineOuter(/*in-out*/Value* min_val, /*in-out*/Value* max_val) {
+ Value v1 = RefineOuter(*min_val, /* is_min */ true);
+ Value v2 = RefineOuter(*max_val, /* is_min */ false);
+ if (v1.instruction != min_val->instruction || v2.instruction != max_val->instruction) {
+ *min_val = v1;
+ *max_val = v2;
+ return true;
+ }
+ return false;
+}
+
bool InductionVarRange::CanGenerateCode(HInstruction* context,
HInstruction* instruction,
/*out*/bool* needs_finite_test,
@@ -202,6 +213,8 @@
} else if (IsIntAndGet(instruction->InputAt(1), &value)) {
return AddValue(GetFetch(instruction->InputAt(0), trip, in_body, is_min), Value(value));
}
+ } else if (instruction->IsArrayLength() && instruction->InputAt(0)->IsNewArray()) {
+ return GetFetch(instruction->InputAt(0)->InputAt(0), trip, in_body, is_min);
} else if (is_min) {
// Special case for finding minimum: minimum of trip-count in loop-body is 1.
if (trip != nullptr && in_body && instruction == trip->op_a->fetch) {
@@ -404,6 +417,25 @@
return Value();
}
+InductionVarRange::Value InductionVarRange::RefineOuter(Value v, bool is_min) {
+ if (v.instruction != nullptr) {
+ HLoopInformation* loop =
+ v.instruction->GetBlock()->GetLoopInformation(); // closest enveloping loop
+ if (loop != nullptr) {
+ // Set up loop information.
+ bool in_body = true; // use is always in body of outer loop
+ HInductionVarAnalysis::InductionInfo* info =
+ induction_analysis_->LookupInfo(loop, v.instruction);
+ HInductionVarAnalysis::InductionInfo* trip =
+ induction_analysis_->LookupInfo(loop, loop->GetHeader()->GetLastInstruction());
+ // Try to refine "a x instruction + b" with outer loop range information on instruction.
+ return AddValue(MulValue(Value(v.a_constant), GetVal(info, trip, in_body, is_min)),
+ Value(v.b_constant));
+ }
+ }
+ return v;
+}
+
bool InductionVarRange::GenerateCode(HInstruction* context,
HInstruction* instruction,
HGraph* graph,