From 1ba69fb5a183ed0808123d849560abd19063f770 Mon Sep 17 00:00:00 2001
From: Victor Zverovich <viz@fb.com>
Date: Mon, 21 Feb 2022 07:47:14 -0800
Subject: [PATCH] Remove snprintf FP fallback

---
 include/fmt/core.h       |  1 -
 include/fmt/format-inl.h | 10 +++-------
 include/fmt/format.h     |  3 ---
 3 files changed, 3 insertions(+), 11 deletions(-)

diff --git a/include/fmt/core.h b/include/fmt/core.h
index dbefe110..1c81bbd2 100644
--- a/include/fmt/core.h
+++ b/include/fmt/core.h
@@ -2728,7 +2728,6 @@ struct float_specs {
   bool upper : 1;
   bool locale : 1;
   bool binary32 : 1;
-  bool fallback : 1;
   bool showpoint : 1;
 };
 
diff --git a/include/fmt/format-inl.h b/include/fmt/format-inl.h
index f8fa77e8..988e3a0d 100644
--- a/include/fmt/format-inl.h
+++ b/include/fmt/format-inl.h
@@ -239,7 +239,8 @@ template <typename F> struct basic_fp {
   }
 
   template <typename Float>
-  using is_supported = bool_constant<std::numeric_limits<Float>::digits <= 64>;
+  using is_supported = bool_constant<std::numeric_limits<Float>::is_iec559 &&
+                                     std::numeric_limits<Float>::digits <= 64>;
 
   // Assigns d to this and return true iff predecessor is closer than successor.
   template <typename Float, FMT_ENABLE_IF(is_supported<Float>::value)>
@@ -268,10 +269,7 @@ template <typename F> struct basic_fp {
   }
 
   template <typename Float, FMT_ENABLE_IF(!is_supported<Float>::value)>
-  bool assign(Float) {
-    FMT_ASSERT(false, "");
-    return false;
-  }
+  bool assign(Float) = delete;
 };
 
 using fp = basic_fp<unsigned long long>;
@@ -2207,8 +2205,6 @@ FMT_HEADER_ONLY_CONSTEXPR20 int format_float(Float value, int precision,
     return -precision;
   }
 
-  if (specs.fallback) return snprintf_float(value, precision, specs, buf);
-
   int exp = 0;
   bool use_dragon = true;
   if (!is_fast_float<Float>()) {
diff --git a/include/fmt/format.h b/include/fmt/format.h
index 4b62b3c9..dae4d37e 100644
--- a/include/fmt/format.h
+++ b/include/fmt/format.h
@@ -2260,9 +2260,6 @@ FMT_CONSTEXPR20 auto write(OutputIt out, T value,
     precision = 1;
   }
   if (const_check(std::is_same<T, float>())) fspecs.binary32 = true;
-  using limits = std::numeric_limits<T>;
-  if (const_check(!limits::is_iec559 || limits::digits > 64))
-    fspecs.fallback = true;
   int exp = format_float(convert_float(value), precision, fspecs, buffer);
   fspecs.precision = precision;
   auto fp = big_decimal_fp{buffer.data(), static_cast<int>(buffer.size()), exp};