* Implement a common dims simplifier.

* Fix the include position error.

* Reduce the cpu overhead of broadcast computing.

* first commit

* refine code with template argument

* refine code with template argument

* add ternary broadcast test file

* add ternary broadcast test file

* fix accoriding to ci

* fix op-benchmark ci error

* support int64 non-broadcast

* support broadcast case for int64 index

* fix bug

* support more Arity

* remove some codes

* upgrade patchelf to v0.15.0 to pass CI build

* fix bug

* fix patchelf installation

* add debug flags

* remove useless codes

* fix viterbi_decode and set_value op uts

* remove always enable int64

* first commit

* fix some bugs in code

* fix bugs

* to optimize merge one dimension feature

* first commit

* merged with develop

* merged with develop

* fix merge sequential one dims bugs

* optimize performance of dygraph

* optimize performance of dygraph and elementwise_add

* optimize the trace op

* fix bug

* fix bug

* fix unittest bug

* fix code format

* change sequential logic

* change some quotes

* add some notations

* change wrong note style.

* move elementwise_div grad

* change mutable_data to alloc

* fix compile bugs

* clean distribution_helper, index_impl, aligned_vector code in fluid

* fix conflicts

* move elementwise function to funcs directory

* fix compile bugs

* modify according to comment

* [KP] Add elementwise add xpu, test=develop

* modify the File Permissions

* modify the copyright time

* modify code style

* modify code style

* rename pten dir to phi

* rename namespace to phi

* rename infrt pten dir to phi

* resolve conflict

* rename pten to phi in cmake

* revert all infrt change

* change needed files

* fix infrt failed

* fix inference failed