Index: tools/llvm-exegesis/lib/Analysis.cpp
===================================================================
--- tools/llvm-exegesis/lib/Analysis.cpp
+++ tools/llvm-exegesis/lib/Analysis.cpp
@@ -12,6 +12,7 @@
 #include "llvm/ADT/STLExtras.h"
 #include "llvm/MC/MCAsmInfo.h"
 #include "llvm/Support/FormatVariadic.h"
+#include <limits>
 #include <unordered_set>
 #include <vector>
 
@@ -95,7 +96,9 @@
 
 template <EscapeTag Tag>
 static void writeMeasurementValue(llvm::raw_ostream &OS, const double Value) {
-  writeEscaped<Tag>(OS, llvm::formatv("{0:F}", Value).str());
+  writeEscaped<Tag>(
+      OS, llvm::formatv("{0:F}", Value)
+              .sstr<1 + std::numeric_limits<decltype(Value)>::max_digits10>());
 }
 
 template <typename EscapeTag, EscapeTag Tag>