Hlo parser: support fusion.

Also,
- Add a HloInstruction::CreateFusion interface that creates a fusion instruction with given fusion computation. Add a HloComputation::SetFusionInstruction interface to help do that.
- Change how we print fusion kind. Before this change we print fusion kind together with the opcode, e.g., fusion:kLoop, which is not easy to parse. Now we append fusion kind as an attribute.
- Print fusion computation the same way as other computations, instead of nested in an instruction.

PiperOrigin-RevId: 175621768

1 files changed, 3 insertions, 0 deletions

diff --git a/tensorflow/compiler/xla/service/hlo_computation.h b/tensorflow/compiler/xla/service/hlo_computation.h
index c9782cc981..2835dbbb84 100644
--- a/tensorflow/compiler/xla/service/hlo_computation.h
+++ b/tensorflow/compiler/xla/service/hlo_computation.h
@@ -326,6 +326,9 @@ class HloComputation {
   // Returns the owning fusion instruction, or nullptr if this is not a fusion
   // computation.
   HloInstruction* FusionInstruction() const { return fusion_instruction_; }
+  void SetFusionInstruction(HloInstruction* fusion_instruction) {
+    fusion_instruction_ = fusion_instruction;
+  }
 
  private:
   explicit HloComputation(