Fix assertion when input is an empty string.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@64397 91177308-0d34-0410-b5e6-96231b3b80d8

diff --git a/lib/Lex/PTHLexer.cpp b/lib/Lex/PTHLexer.cpp
index 4648ac8ee4926011306a7ebf6eb33e5247ed19df..0cd17e74a4b7aa35ab4a325f302820dfffc47e46 100644 (file)
--- a/lib/Lex/PTHLexer.cpp
+++ b/lib/Lex/PTHLexer.cpp
@@ -721,7 +721,7 @@ IdentifierInfo* PTHManager::LazilyCreateIdentifierInfo(unsigned PersistentID) {
 IdentifierInfo* PTHManager::get(const char *NameStart, const char *NameEnd) {
   PTHStringIdLookup& SL = *((PTHStringIdLookup*)StringIdLookup);
   // Double check our assumption that the last character isn't '\0'.
-  assert(NameStart[NameEnd-NameStart-1] != '\0');
+  assert(NameEnd==NameStart || NameStart[NameEnd-NameStart-1] != '\0');
   PTHStringIdLookup::iterator I = SL.find(std::make_pair(NameStart,
                                                          NameEnd - NameStart));
   if (I == SL.end()) // No identifier found?