Generalize range analysis.

Rationale:
obvious case x+-1 vs x-1 was missing

Test: test-art-host
Bug: 63631713
Change-Id: I0a97548a509239bee34a099b1ce9856bac311dba

1 files changed, 9 insertions, 0 deletions

diff --git a/compiler/optimizing/induction_var_range.cc b/compiler/optimizing/induction_var_range.cc
index 089340e715..191d3d128c 100644
--- a/compiler/optimizing/induction_var_range.cc
+++ b/compiler/optimizing/induction_var_range.cc
@@ -670,6 +670,15 @@ InductionVarRange::Value InductionVarRange::GetFetch(HInstruction* instruction,
       return AddValue(GetFetch(instruction->InputAt(0), trip, in_body, is_min),
                       Value(static_cast<int32_t>(value)));
     }
+  } else if (instruction->IsSub()) {
+    // Incorporate suitable constants in the chased value.
+    if (IsInt64AndGet(instruction->InputAt(0), &value) && CanLongValueFitIntoInt(value)) {
+      return SubValue(Value(static_cast<int32_t>(value)),
+                      GetFetch(instruction->InputAt(1), trip, in_body, !is_min));
+    } else if (IsInt64AndGet(instruction->InputAt(1), &value) && CanLongValueFitIntoInt(value)) {
+      return SubValue(GetFetch(instruction->InputAt(0), trip, in_body, is_min),
+                      Value(static_cast<int32_t>(value)));
+    }
   } else if (instruction->IsArrayLength()) {
     // Exploit length properties when chasing constants or chase into a new array declaration.
     if (chase_hint_ == nullptr) {