Fix some serious logical errors in CStrInCStrNoCase pointed out by Bill.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@50826 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 8 insertions, 5 deletions

diff --git a/include/llvm/ADT/StringExtras.h b/include/llvm/ADT/StringExtras.h
index e3b3c8770a..8ce53fc67b 100644
--- a/include/llvm/ADT/StringExtras.h
+++ b/include/llvm/ADT/StringExtras.h
@@ -144,26 +144,29 @@ static inline bool StringsEqualNoCase(const std::string &LHS,
   
 /// CStrInCStrNoCase - Portable version of strcasestr.  Locates the first
 ///  occurance of c-string 's1' in string 's2', ignoring case.  Returns
-///  NULL if 's1' cannot be found.
+///  NULL if 's1' cannot be found.  NOTE: the arguments are provided
+///  in a different order than strcasestr.
 static inline const char* CStrInCStrNoCase(const char *s1, const char *s2) {
 
   // Are either strings NULL or empty?
   if (!s1 || !s2 || s1[0] == '\0' || s2[0] == '\0')
     return 0;
   
+  if (s1 == s2)
+    return s1;
+  
   const char *I1=s1, *I2=s2;
   
   while (*I1 != '\0' || *I2 != '\0' )
     if (tolower(*I1) != tolower(*I2)) { // No match.  Start over.
-      ++s1; I1 = s1; I2 = s2;
+      ++s2; I1 = s1; I2 = s2;
     }
     else { // Character match.  Advance to the next character.
       ++I1; ++I2;
     }
 
-  // If we exhausted all of the characters in 's2', then 's1' does not occur
-  // in it.
-  return *I2 == '\0' ? 0 : I1;
+  // If we exhausted all of the characters in 's1', then 's1' appears in 's2'.
+  return *I1 == '\0' ? s2 : 0;
 }
 
 /// getToken - This function extracts one token from source, ignoring any