SimplifyLibCalls: Add basic optimization of memchr calls.

[oota-llvm.git] / include / llvm / ADT / StringRef.h

diff --git a/include/llvm/ADT/StringRef.h b/include/llvm/ADT/StringRef.h
index 6111c42da9dced36ed905fb0e715865b0f4cdd91..4d491e8606ac5d834902edbb9cec219d64759266 100644 (file)
--- a/include/llvm/ADT/StringRef.h
+++ b/include/llvm/ADT/StringRef.h
@@ -238,9 +238,12 @@ namespace llvm {
     /// \returns The index of the first occurrence of \p C, or npos if not
     /// found.
     size_t find(char C, size_t From = 0) const {
-      for (size_t i = std::min(From, Length), e = Length; i != e; ++i)
-        if (Data[i] == C)
-          return i;
+      if (Length != 0) {
+        size_t FindBegin = std::min(From, Length);
+        if (const void *Found =
+                std::memchr(Data + FindBegin, C, Length - FindBegin))
+          return static_cast<const char *>(Found) - Data;
+      }
       return npos;
     }