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, 4 insertions, 3 deletions

diff --git a/tensorflow/compiler/xla/service/hlo_instruction_test.cc b/tensorflow/compiler/xla/service/hlo_instruction_test.cc
index 4ead64d997..41b916e2c7 100644
--- a/tensorflow/compiler/xla/service/hlo_instruction_test.cc
+++ b/tensorflow/compiler/xla/service/hlo_instruction_test.cc
@@ -1195,9 +1195,10 @@ TEST_F(HloInstructionTest, Stringification) {
   HloInstruction* fusion = computation->CreateFusionInstruction(
       {dot, reshape}, HloInstruction::FusionKind::kTransposeDot);
 
-  EXPECT_EQ(fusion->ToString(false, false),
-            "%fusion = f32[5,20]{1,0} fusion:kTransposeDot(f32[5,10]{1,0} %x, "
-            "f32[20,10]{1,0} %y), calls=%fused_computation");
+  EXPECT_EQ(
+      fusion->ToString(false, false),
+      "%fusion = f32[5,20]{1,0} fusion(f32[5,10]{1,0} %x, "
+      "f32[20,10]{1,0} %y), kind=kTransposeDot, calls=%fused_computation");
 
   HloInstruction* loop = builder.AddInstruction(
       HloInstruction::CreateWhile(sout, computation, computation, x));