diff --git a/include/Support/StringExtras.h b/include/Support/StringExtras.h
index 9233d6c0cd4..0596b2feb55 100644
--- a/include/Support/StringExtras.h
+++ b/include/Support/StringExtras.h
@@ -80,7 +80,7 @@ static inline std::string itostr(int X) {
 
 static inline std::string ftostr(double V) {
   char Buffer[200];
-  snprintf(Buffer, 200, "%e", V);
+  snprintf(Buffer, 200, "%20.6e", V);
   return Buffer;
 }
 
diff --git a/include/llvm/ADT/StringExtras.h b/include/llvm/ADT/StringExtras.h
index 9233d6c0cd4..0596b2feb55 100644
--- a/include/llvm/ADT/StringExtras.h
+++ b/include/llvm/ADT/StringExtras.h
@@ -80,7 +80,7 @@ static inline std::string itostr(int X) {
 
 static inline std::string ftostr(double V) {
   char Buffer[200];
-  snprintf(Buffer, 200, "%e", V);
+  snprintf(Buffer, 200, "%20.6e", V);
   return Buffer;
 }