Index: utils/FileCheck/FileCheck.cpp
===================================================================
--- utils/FileCheck/FileCheck.cpp
+++ utils/FileCheck/FileCheck.cpp
@@ -405,7 +405,7 @@
   unsigned LineCount = InputFileText.count('\n');
   if (InputFileEnd[-1] != '\n')
     ++LineCount;
-  unsigned LineNoWidth = log10(LineCount) + 1;
+  unsigned LineNoWidth = log10((double)LineCount) + 1;
   // +3 below adds spaces (1) to the left of the (right-aligned) line numbers
   // on input lines and (2) to the right of the (left-aligned) labels on
   // annotation lines so that input lines and annotation lines are more