NFC: deduplicate isRepeatedBytePattern from clang to LLVM's isBytewiseValue
Summary:
This code was in CGDecl.cpp and really belongs in LLVM. It happened to have isBytewiseValue which served a very similar purpose but wasn't as powerful as clang's version. Remove the clang version, and augment isBytewiseValue to be as powerful so that clang does the same thing it used to.
LLVM part of this patch: D51751
Subscribers: dexonsmith, cfe-commits
Differential Revision: https://reviews.llvm.org/D51752
llvm-svn: 342734