1 files changed, 10 insertions, 0 deletions
diff --git a/compiler/optimizing/locations.h b/compiler/optimizing/locations.h
index 63bbc2cd0a..3f27c911be 100644
--- a/compiler/optimizing/locations.h
+++ b/compiler/optimizing/locations.h
@@ -38,7 +38,13 @@ std::ostream& operator<<(std::ostream& os, const Location& location);
 class Location : public ValueObject {
  public:
   enum OutputOverlap {
+    // The liveness of the output overlaps the liveness of one or
+    // several input(s); the register allocator cannot reuse an
+    // input's location for the output's location.
     kOutputOverlap,
+    // The liveness of the output does not overlap the liveness of any
+    // input; the register allocator is allowed to reuse an input's
+    // location for the output's location.
     kNoOutputOverlap
   };
 
@@ -494,6 +500,10 @@ class LocationSummary : public ArenaObject<kArenaAllocLocationSummary> {
     return inputs_.size();
   }
 
+  // Set the output location.  Argument `overlaps` tells whether the
+  // output overlaps any of the inputs (if so, it cannot share the
+  // same register as one of the inputs); it is set to
+  // `Location::kOutputOverlap` by default for safety.
   void SetOut(Location location, Location::OutputOverlap overlaps = Location::kOutputOverlap) {
     DCHECK(output_.IsInvalid());
     output_overlaps_ = overlaps;