[libc-commits] [libc] [libc][math][c23] Add exp2m1f C23 math function (PR #86996)

[via libc-commits]

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@@ -0,0 +1,182 @@
+//===-- Implementation of exp2m1f function --------------------------------===//
+//
+// 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
+//
+//===----------------------------------------------------------------------===//
+
+#include "src/math/exp2m1f.h"
+#include "src/__support/FPUtil/FEnvImpl.h"
+#include "src/__support/FPUtil/FPBits.h"
+#include "src/__support/FPUtil/PolyEval.h"
+#include "src/__support/FPUtil/except_value_utils.h"
+#include "src/__support/FPUtil/multiply_add.h"
+#include "src/__support/FPUtil/rounding_mode.h"
+#include "src/__support/common.h"
+#include "src/__support/macros/optimization.h"
+#include "src/__support/macros/properties/cpu_features.h"
+#include "src/errno/libc_errno.h"
+
+#include "explogxf.h"
+
+namespace LIBC_NAMESPACE {
+
+static constexpr size_t N_EXCEPTS_LO = 8;
+
+static constexpr fputil::ExceptValues<float, N_EXCEPTS_LO> EXP2M1F_EXCEPTS_LO =
+    {{
+        // (input, RZ output, RU offset, RD offset, RN offset)
+        // x = 0x1.36dc8ep-36, exp2m1f(x) = 0x1.aef212p-37 (RZ)
+        {0x2d9b'6e47U, 0x2d57'7909U, 1U, 0U, 0U},
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overmighty wrote:

Yes but existing code sometimes doesn't use the `U` suffix in literals that initialize variables of unsigned integer types and in literals that are compared against variables of unsigned integer types, and sometimes uses it. I'm not sure if there's a rule for this or if it just doesn't really matter if it's inconsistent.

https://github.com/llvm/llvm-project/pull/86996