message: [XLA] Fix a latent bug. Currently I think the code is fine, but the function doesn't do what its name say.
diff: @@ -506,7 +506,7 @@ llvm::Value* IsBlock0Thread0(llvm::IRBuilder<>* b) {
  EmitCallToTargetIntrinsic(TargetIntrinsicID::kThreadIdx, {}, {}, b)),
  b->CreateICmpEQ(
  b->getInt32(0),
  - EmitCallToTargetIntrinsic(TargetIntrinsicID::kThreadIdx, {}, {}, b)));
  + EmitCallToTargetIntrinsic(TargetIntrinsicID::kBlockIdx, {}, {}, b)));
  }
  bool AreFusedReductionOutputsConsistent(
  