Improve the performance of filename canonicalization by avoiding redundant searches in the string. No functionality change.
Improve the performance of filename canonicalization by avoiding
redundant searches in the string. No functionality change.


git-svn-id: ffe668792ed300d6c2daa1f6eba2e0aa28d7ec6c@124760 91177308-0d34-0410-b5e6-96231b3b80d8

llvm-mirror/clang,llvm-mirror/clang,apple/swift-clang,llvm-mirror/clang,apple/swift-clang,apple/swift-clang,apple/swift-clang,apple/swift-clang,apple/swift-clang,llvm-mirror/clang,llvm-mirror/clang,apple/swift-clang,llvm-mirror/clang,apple/swift-clang,llvm-mirror/clang,llvm-mirror/clang,llvm-mirror/clang,apple/swift-clang,apple/swift-clang,llvm-mirror/clang