[libc-commits] [libc] [llvm] [libc][math] Optimize exp and share double-precision evaluation with exp2. (PR #233018)

[via libc-commits]

================
@@ -0,0 +1,153 @@
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+///
+/// \file
+/// Double-precision implementation of exp.
+///
+//===----------------------------------------------------------------------===//
+
+#ifndef LLVM_LIBC_SRC___SUPPORT_MATH_EXP_DOUBLE_EVAL_H
+#define LLVM_LIBC_SRC___SUPPORT_MATH_EXP_DOUBLE_EVAL_H
+
+#include "src/__support/FPUtil/FPBits.h"
+#include "src/__support/FPUtil/double_double.h"
+#include "src/__support/FPUtil/multiply_add.h"
+#include "src/__support/FPUtil/nearest_integer.h"
+#include "src/__support/common.h"
+#include "src/__support/macros/attributes.h"
+#include "src/__support/macros/config.h"
+#include "src/__support/macros/optimization.h"
+#include "src/__support/macros/properties/cpu_features.h"
+
+#ifdef LIBC_MATH_HAS_SKIP_ACCURATE_PASS
+#include "src/__support/math/exp_double_utils.h"
+#else
+#include "src/__support/math/exp_utils.h"
+#endif // LIBC_MATH_HAS_SKIP_ACCURATE_PASS
+
+namespace LIBC_NAMESPACE_DECL {
+namespace math {
+namespace double_eval {
+
+LIBC_ALWAYS_INLINE double exp(double x) {
+  using FPBits = typename fputil::FPBits<double>;
----------------
Sukumarsawant wrote:

small nit if typename is required here

https://github.com/llvm/llvm-project/pull/233018