[ADT] Compare strings' hashes first before comparing their values.

Summary:
We already have the hashes in hand, and comparing hashes should be much
more discriminatory than comparing the StringRefs' sizes.

Reviewers: rafael

Subscribers: llvm-commits

Differential Revision: https://reviews.llvm.org/D25705

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@284872 91177308-0d34-0410-b5e6-96231b3b80d8
1 file changed