[XLA] Document and enforce reduction order of init value

All existing backends apply the init_value on the lhs, except for the evaluator.  This causes problems for reductions which apply an identity function to a reduce or reduce window.

PiperOrigin-RevId: 193091323

1 files changed, 1 insertions, 1 deletions

diff --git a/tensorflow/compiler/xla/service/algebraic_simplifier.cc b/tensorflow/compiler/xla/service/algebraic_simplifier.cc
index cd5737e4f9..8d26938c6e 100644
--- a/tensorflow/compiler/xla/service/algebraic_simplifier.cc
+++ b/tensorflow/compiler/xla/service/algebraic_simplifier.cc
@@ -1695,7 +1695,7 @@ Status AlgebraicSimplifierVisitor::HandleReduce(HloInstruction* reduce) {
         HloInstruction::CreateReshape(reduce->shape(), arg));
     return ReplaceWithNewInstruction(
         reduce, HloInstruction::CreateMap(reduce->shape(),
-                                          {reshape, init_value}, function));
+                                          {init_value, reshape}, function));
   }
   return Status::OK();
 }