From cdf877d4b121f2166cb44f6df0957edc43b6a58a Mon Sep 17 00:00:00 2001
From: Victor Zverovich <victor.zverovich@gmail.com>
Date: Thu, 11 Mar 2021 16:44:59 -0800
Subject: [PATCH] Workaround missed optimization opportunity

---
 include/fmt/format.h | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/include/fmt/format.h b/include/fmt/format.h
index 83437f63..1e6f851b 100644
--- a/include/fmt/format.h
+++ b/include/fmt/format.h
@@ -1685,7 +1685,8 @@ template <typename OutputIt, typename Char, typename W>
 FMT_CONSTEXPR FMT_INLINE OutputIt
 write_int(OutputIt out, int num_digits, string_view prefix,
           const basic_format_specs<Char>& specs, W write_digits) {
-  if (specs.width == 0 && specs.precision < 0) {
+  // Slightly faster check for specs.width == 0 && specs.precision == -1.
+  if ((specs.width | (specs.precision + 1)) == 0) {
     auto it = reserve(out, to_unsigned(num_digits) + prefix.size());
     if (prefix.size() != 0)
       it = copy_str<Char>(prefix.begin(), prefix.end(), it);