TargetLibraryInfo: Introduce wcslen

wcslen is part of the C99 and C++98 standards.

- This introduces the function to TargetLibraryInfo.
- Also set attributes for wcslen in llvm::inferLibFuncAttributes().

Differential Revision: https://reviews.llvm.org/D32837

llvm-svn: 302278
diff --git a/llvm/lib/Transforms/Utils/BuildLibCalls.cpp b/llvm/lib/Transforms/Utils/BuildLibCalls.cpp
index 1956697..ebde1f9 100644
--- a/llvm/lib/Transforms/Utils/BuildLibCalls.cpp
+++ b/llvm/lib/Transforms/Utils/BuildLibCalls.cpp
@@ -113,6 +113,7 @@
   bool Changed = false;
   switch (TheLibFunc) {
   case LibFunc_strlen:
+  case LibFunc_wcslen:
     Changed |= setOnlyReadsMemory(F);
     Changed |= setDoesNotThrow(F);
     Changed |= setDoesNotCapture(F, 0);