From b1ba3e6d5c608b16f05adc6d331ec22a6ed443ae Mon Sep 17 00:00:00 2001
From: Victor Zverovich <viz@fb.com>
Date: Sat, 2 Oct 2021 06:06:08 -0700
Subject: [PATCH] Refactor Windows workarounds

---
 include/fmt/core.h   |  3 ---
 include/fmt/format.h | 35 ++++++++++++++++++-----------------
 2 files changed, 18 insertions(+), 20 deletions(-)

diff --git a/include/fmt/core.h b/include/fmt/core.h
index 7a66433e9fd42..18cdf2237d042 100644
--- a/include/fmt/core.h
+++ b/include/fmt/core.h
@@ -34,13 +34,10 @@
 
 #ifdef __ICL
 #  define FMT_ICC_VERSION __ICL
-#  define FMT_ICC_INTRINSIC_BUG 1
 #elif defined(__INTEL_COMPILER)
 #  define FMT_ICC_VERSION __INTEL_COMPILER
-#  define FMT_ICC_INTRINSIC_BUG 0
 #else
 #  define FMT_ICC_VERSION 0
-#  define FMT_ICC_INTRINSIC_BUG 0
 #endif
 
 #ifdef __NVCC__
diff --git a/include/fmt/format.h b/include/fmt/format.h
index 9e132fa1f346b..23dbe1d9fbe69 100644
--- a/include/fmt/format.h
+++ b/include/fmt/format.h
@@ -162,24 +162,25 @@ FMT_END_NAMESPACE
 #endif
 
 // __builtin_clz is broken in clang with Microsoft CodeGen:
-// https://github.com/fmtlib/fmt/issues/519
-#if (FMT_GCC_VERSION || FMT_HAS_BUILTIN(__builtin_clz) || FMT_ICC_VERSION) && \
-    !FMT_MSC_VER
-#  define FMT_BUILTIN_CLZ(n) __builtin_clz(n)
-#endif
-#if (FMT_GCC_VERSION || FMT_HAS_BUILTIN(__builtin_clzll) || \
-     FMT_ICC_VERSION) &&                                    \
-    !FMT_MSC_VER
-#  define FMT_BUILTIN_CLZLL(n) __builtin_clzll(n)
-#endif
-#if (FMT_GCC_VERSION || FMT_HAS_BUILTIN(__builtin_ctz) || FMT_ICC_VERSION) && \
-    !FMT_ICC_INTRINSIC_BUG
-#  define FMT_BUILTIN_CTZ(n) __builtin_ctz(n)
+// https://github.com/fmtlib/fmt/issues/519.
+#ifndef FMT_MSC_VER
+#  if FMT_HAS_BUILTIN(__builtin_clz) || FMT_GCC_VERSION || FMT_ICC_VERSION
+#    define FMT_BUILTIN_CLZ(n) __builtin_clz(n)
+#  endif
+#  if FMT_HAS_BUILTIN(__builtin_clzll) || FMT_GCC_VERSION || FMT_ICC_VERSION
+#    define FMT_BUILTIN_CLZLL(n) __builtin_clzll(n)
+#  endif
 #endif
-#if (FMT_GCC_VERSION || FMT_HAS_BUILTIN(__builtin_ctzll) || \
-     FMT_ICC_VERSION) &&                                    \
-    !FMT_ICC_INTRINSIC_BUG
-#  define FMT_BUILTIN_CTZLL(n) __builtin_ctzll(n)
+
+// __builtin_ctz is broken in Intel Compiler Classic on Windows:
+// https://github.com/fmtlib/fmt/issues/2510.
+#ifndef __ICL
+#  if FMT_HAS_BUILTIN(__builtin_ctz) || FMT_GCC_VERSION || FMT_ICC_VERSION
+#    define FMT_BUILTIN_CTZ(n) __builtin_ctz(n)
+#  endif
+#  if FMT_HAS_BUILTIN(__builtin_ctzll) || FMT_GCC_VERSION || FMT_ICC_VERSION
+#    define FMT_BUILTIN_CTZLL(n) __builtin_ctzll(n)
+#  endif
 #endif
 
 #if FMT_MSC_VER