bce: handle a pattern for circular buffer
Change-Id: Ie54bdd7c044af58deea0d0addaaa8186cabf3532
diff --git a/compiler/optimizing/bounds_check_elimination.cc b/compiler/optimizing/bounds_check_elimination.cc
index 811a3bd..deaeb8e 100644
--- a/compiler/optimizing/bounds_check_elimination.cc
+++ b/compiler/optimizing/bounds_check_elimination.cc
@@ -823,6 +823,21 @@
FindAndHandlePartialArrayLength(ushr);
}
+ void VisitAnd(HAnd* instruction) {
+ if (instruction->GetRight()->IsIntConstant()) {
+ int32_t constant = instruction->GetRight()->AsIntConstant()->GetValue();
+ if (constant > 0) {
+ // constant serves as a mask so any number masked with it
+ // gets a [0, constant] value range.
+ ValueRange* range = new (GetGraph()->GetArena()) ValueRange(
+ GetGraph()->GetArena(),
+ ValueBound(nullptr, 0),
+ ValueBound(nullptr, constant));
+ GetValueRangeMap(instruction->GetBlock())->Overwrite(instruction->GetId(), range);
+ }
+ }
+ }
+
void VisitNewArray(HNewArray* new_array) {
HInstruction* len = new_array->InputAt(0);
if (!len->IsIntConstant()) {