[libc-commits] [libc] 6cb14ad - [libc][math] Implement scalbn, scalbnf, scalbnl.

Siva Chandra Reddy via libc-commits libc-commits at lists.llvm.org
Wed Feb 8 21:56:07 PST 2023


Author: Renyi Chen
Date: 2023-02-09T05:55:34Z
New Revision: 6cb14adbfa95fd7033bd02198530ab74a313549d

URL: https://github.com/llvm/llvm-project/commit/6cb14adbfa95fd7033bd02198530ab74a313549d
DIFF: https://github.com/llvm/llvm-project/commit/6cb14adbfa95fd7033bd02198530ab74a313549d.diff

LOG: [libc][math] Implement scalbn, scalbnf, scalbnl.

Implement scalbn via `fptuil::ldexp` for `FLT_RADIX==2` case.
"unimplemented" otherwise.

Reviewed By: lntue, sivachandra

Differential Revision: https://reviews.llvm.org/D143116

Added: 
    libc/src/math/generic/scalbn.cpp
    libc/src/math/generic/scalbnf.cpp
    libc/src/math/generic/scalbnl.cpp
    libc/src/math/scalbn.h
    libc/src/math/scalbnf.h
    libc/src/math/scalbnl.h
    libc/test/src/math/ScalbnTest.h
    libc/test/src/math/scalbn_test.cpp
    libc/test/src/math/scalbnf_test.cpp
    libc/test/src/math/scalbnl_test.cpp

Modified: 
    libc/config/darwin/arm/entrypoints.txt
    libc/config/linux/aarch64/entrypoints.txt
    libc/config/linux/x86_64/entrypoints.txt
    libc/config/windows/entrypoints.txt
    libc/docs/math.rst
    libc/spec/stdc.td
    libc/src/__support/FPUtil/ManipulationFunctions.h
    libc/src/math/CMakeLists.txt
    libc/src/math/generic/CMakeLists.txt
    libc/test/src/math/CMakeLists.txt

Removed: 
    


################################################################################
diff  --git a/libc/config/darwin/arm/entrypoints.txt b/libc/config/darwin/arm/entrypoints.txt
index 7c24148afd48b..405f27cff412e 100644
--- a/libc/config/darwin/arm/entrypoints.txt
+++ b/libc/config/darwin/arm/entrypoints.txt
@@ -198,6 +198,9 @@ set(TARGET_LIBM_ENTRYPOINTS
     libc.src.math.round
     libc.src.math.roundf
     libc.src.math.roundl
+    libc.src.math.scalbn
+    libc.src.math.scalbnf
+    libc.src.math.scalbnl
     libc.src.math.sincosf
     libc.src.math.sinhf
     libc.src.math.sinf

diff  --git a/libc/config/linux/aarch64/entrypoints.txt b/libc/config/linux/aarch64/entrypoints.txt
index 7e9b2030c3883..e2826effc29ab 100644
--- a/libc/config/linux/aarch64/entrypoints.txt
+++ b/libc/config/linux/aarch64/entrypoints.txt
@@ -300,6 +300,9 @@ set(TARGET_LIBM_ENTRYPOINTS
     libc.src.math.round
     libc.src.math.roundf
     libc.src.math.roundl
+    libc.src.math.scalbn
+    libc.src.math.scalbnf
+    libc.src.math.scalbnl
     libc.src.math.sincosf
     libc.src.math.sinhf
     libc.src.math.sinf

diff  --git a/libc/config/linux/x86_64/entrypoints.txt b/libc/config/linux/x86_64/entrypoints.txt
index 7187c7f203369..e4fe2467b75bb 100644
--- a/libc/config/linux/x86_64/entrypoints.txt
+++ b/libc/config/linux/x86_64/entrypoints.txt
@@ -302,6 +302,9 @@ set(TARGET_LIBM_ENTRYPOINTS
     libc.src.math.round
     libc.src.math.roundf
     libc.src.math.roundl
+    libc.src.math.scalbn
+    libc.src.math.scalbnf
+    libc.src.math.scalbnl
     libc.src.math.sin
     libc.src.math.sincosf
     libc.src.math.sinhf

diff  --git a/libc/config/windows/entrypoints.txt b/libc/config/windows/entrypoints.txt
index 217bed253e673..d7b15cf5fc6dd 100644
--- a/libc/config/windows/entrypoints.txt
+++ b/libc/config/windows/entrypoints.txt
@@ -202,6 +202,9 @@ set(TARGET_LIBM_ENTRYPOINTS
     libc.src.math.round
     libc.src.math.roundf
     libc.src.math.roundl
+    libc.src.math.scalbn
+    libc.src.math.scalbnf
+    libc.src.math.scalbnl
     libc.src.math.sin
     libc.src.math.sincosf
     libc.src.math.sinf

diff  --git a/libc/docs/math.rst b/libc/docs/math.rst
index 25da4c5e9e710..3838214b9e04e 100644
--- a/libc/docs/math.rst
+++ b/libc/docs/math.rst
@@ -110,7 +110,7 @@ remainder      :green:`XA`      :green:`XA`     :green:`XA`
 remquo         :green:`XA`      :green:`XA`     :green:`XA`
 rint           :green:`XA`      :green:`XA`     :green:`XA`
 round          :green:`XA`      :green:`XA`     :green:`XA`
-scalbn
+scalbn         :green:`XA`      :green:`XA`     :green:`XA`
 signbit
 trunc          :green:`XA`      :green:`XA`     :green:`XA`
 ============== ================ =============== ======================

diff  --git a/libc/spec/stdc.td b/libc/spec/stdc.td
index 11d2c702a7ca2..84277f099a13c 100644
--- a/libc/spec/stdc.td
+++ b/libc/spec/stdc.td
@@ -495,6 +495,10 @@ def StdC : StandardSpec<"stdc"> {
           FunctionSpec<"acoshf", RetValSpec<FloatType>, [ArgSpec<FloatType>]>,
           FunctionSpec<"asinhf", RetValSpec<FloatType>, [ArgSpec<FloatType>]>,
           FunctionSpec<"atanhf", RetValSpec<FloatType>, [ArgSpec<FloatType>]>,
+
+          FunctionSpec<"scalbn", RetValSpec<DoubleType>, [ArgSpec<DoubleType>, ArgSpec<IntType>]>,
+          FunctionSpec<"scalbnf", RetValSpec<FloatType>, [ArgSpec<FloatType>, ArgSpec<IntType>]>,
+          FunctionSpec<"scalbnl", RetValSpec<LongDoubleType>, [ArgSpec<LongDoubleType>, ArgSpec<IntType>]>,
       ]
   >;
 

diff  --git a/libc/src/__support/FPUtil/ManipulationFunctions.h b/libc/src/__support/FPUtil/ManipulationFunctions.h
index 946d35c03b1ce..5d29f5445a0d2 100644
--- a/libc/src/__support/FPUtil/ManipulationFunctions.h
+++ b/libc/src/__support/FPUtil/ManipulationFunctions.h
@@ -116,8 +116,10 @@ LIBC_INLINE T logb(T x) {
 
 template <typename T, cpp::enable_if_t<cpp::is_floating_point_v<T>, int> = 0>
 LIBC_INLINE T ldexp(T x, int exp) {
+  if (unlikely(exp == 0))
+    return x;
   FPBits<T> bits(x);
-  if (bits.is_zero() || bits.is_inf_or_nan() || exp == 0)
+  if (unlikely(bits.is_zero() || bits.is_inf_or_nan()))
     return x;
 
   // NormalFloat uses int32_t to store the true exponent value. We should ensure

diff  --git a/libc/src/math/CMakeLists.txt b/libc/src/math/CMakeLists.txt
index 5ae47764b81b0..78bab469c28db 100644
--- a/libc/src/math/CMakeLists.txt
+++ b/libc/src/math/CMakeLists.txt
@@ -192,6 +192,10 @@ add_math_entrypoint_object(round)
 add_math_entrypoint_object(roundf)
 add_math_entrypoint_object(roundl)
 
+add_math_entrypoint_object(scalbn)
+add_math_entrypoint_object(scalbnf)
+add_math_entrypoint_object(scalbnl)
+
 add_math_entrypoint_object(sincosf)
 
 add_math_entrypoint_object(sin)

diff  --git a/libc/src/math/generic/CMakeLists.txt b/libc/src/math/generic/CMakeLists.txt
index 9cbeac2dbd496..b905d3efe5c42 100644
--- a/libc/src/math/generic/CMakeLists.txt
+++ b/libc/src/math/generic/CMakeLists.txt
@@ -1433,3 +1433,39 @@ add_entrypoint_object(
   COMPILE_OPTIONS
     -O3
 )
+
+add_entrypoint_object(
+  scalbn
+  SRCS
+    scalbn.cpp
+  HDRS
+    ../scalbn.h
+  DEPENDS
+    libc.src.__support.FPUtil.manipulation_functions
+  COMPILE_OPTIONS
+    -O3
+)
+
+add_entrypoint_object(
+  scalbnf
+  SRCS
+    scalbnf.cpp
+  HDRS
+    ../scalbnf.h
+  DEPENDS
+    libc.src.__support.FPUtil.manipulation_functions
+  COMPILE_OPTIONS
+    -O3
+)
+
+add_entrypoint_object(
+  scalbnl
+  SRCS
+    scalbnl.cpp
+  HDRS
+    ../scalbnl.h
+  DEPENDS
+    libc.src.__support.FPUtil.manipulation_functions
+  COMPILE_OPTIONS
+    -O3
+)

diff  --git a/libc/src/math/generic/scalbn.cpp b/libc/src/math/generic/scalbn.cpp
new file mode 100644
index 0000000000000..faccf6c378d61
--- /dev/null
+++ b/libc/src/math/generic/scalbn.cpp
@@ -0,0 +1,25 @@
+//===-- Single-precision scalbn 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/scalbn.h"
+#include "src/__support/FPUtil/ManipulationFunctions.h"
+#include "src/__support/common.h"
+
+namespace __llvm_libc {
+
+LLVM_LIBC_FUNCTION(double, scalbn, (double x, int n)) {
+#if !defined(__FLT_RADIX__)
+#error __FLT_RADIX__ undefined.
+#elif __FLT_RADIX__ != 2
+#error __FLT_RADIX__!=2, unimplemented.
+#else
+  return fputil::ldexp(x, n);
+#endif
+}
+
+} // namespace __llvm_libc

diff  --git a/libc/src/math/generic/scalbnf.cpp b/libc/src/math/generic/scalbnf.cpp
new file mode 100644
index 0000000000000..391da1f01cce2
--- /dev/null
+++ b/libc/src/math/generic/scalbnf.cpp
@@ -0,0 +1,25 @@
+//===-- Single-precision scalbnf 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/scalbnf.h"
+#include "src/__support/FPUtil/ManipulationFunctions.h"
+#include "src/__support/common.h"
+
+namespace __llvm_libc {
+
+LLVM_LIBC_FUNCTION(float, scalbnf, (float x, int n)) {
+#if !defined(__FLT_RADIX__)
+#error __FLT_RADIX__ undefined.
+#elif __FLT_RADIX__ != 2
+#error __FLT_RADIX__!=2, unimplemented.
+#else
+  return fputil::ldexp(x, n);
+#endif
+}
+
+} // namespace __llvm_libc

diff  --git a/libc/src/math/generic/scalbnl.cpp b/libc/src/math/generic/scalbnl.cpp
new file mode 100644
index 0000000000000..9ef6f230f4101
--- /dev/null
+++ b/libc/src/math/generic/scalbnl.cpp
@@ -0,0 +1,25 @@
+//===-- Single-precision scalbnl 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/scalbnl.h"
+#include "src/__support/FPUtil/ManipulationFunctions.h"
+#include "src/__support/common.h"
+
+namespace __llvm_libc {
+
+LLVM_LIBC_FUNCTION(long double, scalbnl, (long double x, int n)) {
+#if !defined(__FLT_RADIX__)
+#error __FLT_RADIX__ undefined.
+#elif __FLT_RADIX__ != 2
+#error __FLT_RADIX__!=2, unimplemented.
+#else
+  return fputil::ldexp(x, n);
+#endif
+}
+
+} // namespace __llvm_libc

diff  --git a/libc/src/math/scalbn.h b/libc/src/math/scalbn.h
new file mode 100644
index 0000000000000..e24f29e4d466e
--- /dev/null
+++ b/libc/src/math/scalbn.h
@@ -0,0 +1,18 @@
+//===-- Implementation header for scalbn ------------------------*- C++ -*-===//
+//
+// 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
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef LLVM_LIBC_SRC_MATH_SCALBN_H
+#define LLVM_LIBC_SRC_MATH_SCALBN_H
+
+namespace __llvm_libc {
+
+double scalbn(double x, int n);
+
+} // namespace __llvm_libc
+
+#endif // LLVM_LIBC_SRC_MATH_SCALBN_H

diff  --git a/libc/src/math/scalbnf.h b/libc/src/math/scalbnf.h
new file mode 100644
index 0000000000000..f5316eed29261
--- /dev/null
+++ b/libc/src/math/scalbnf.h
@@ -0,0 +1,18 @@
+//===-- Implementation header for scalbnf -----------------------*- C++ -*-===//
+//
+// 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
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef LLVM_LIBC_SRC_MATH_SCALBNF_H
+#define LLVM_LIBC_SRC_MATH_SCALBNF_H
+
+namespace __llvm_libc {
+
+float scalbnf(float x, int n);
+
+} // namespace __llvm_libc
+
+#endif // LLVM_LIBC_SRC_MATH_SCALBNF_H

diff  --git a/libc/src/math/scalbnl.h b/libc/src/math/scalbnl.h
new file mode 100644
index 0000000000000..6839a75072cd6
--- /dev/null
+++ b/libc/src/math/scalbnl.h
@@ -0,0 +1,18 @@
+//===-- Implementation header for scalbnl -----------------------*- C++ -*-===//
+//
+// 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
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef LLVM_LIBC_SRC_MATH_SCALBNL_H
+#define LLVM_LIBC_SRC_MATH_SCALBNL_H
+
+namespace __llvm_libc {
+
+long double scalbnl(long double x, int n);
+
+} // namespace __llvm_libc
+
+#endif // LLVM_LIBC_SRC_MATH_SCALBNL_H

diff  --git a/libc/test/src/math/CMakeLists.txt b/libc/test/src/math/CMakeLists.txt
index 8b559c3e9c3eb..54cabf89c87ab 100644
--- a/libc/test/src/math/CMakeLists.txt
+++ b/libc/test/src/math/CMakeLists.txt
@@ -1574,9 +1574,57 @@ add_fp_unittest(
   SRCS
     pow_test.cpp
   DEPENDS
-  libc.include.errno
-  libc.src.errno.errno
-  libc.src.math.pow
+    libc.include.errno
+    libc.src.errno.errno
+    libc.src.math.pow
+)
+
+add_fp_unittest(
+  scalbn_test
+  NEED_MPFR
+  SUITE
+    libc_math_unittests
+  SRCS
+    scalbn_test.cpp
+  HDRS
+    ScalbnTest.h
+  DEPENDS
+    libc.include.math
+    libc.src.math.scalbn
+    libc.src.__support.FPUtil.fp_bits
+    libc.src.__support.FPUtil.normal_float
+)
+
+add_fp_unittest(
+  scalbnf_test
+  NEED_MPFR
+  SUITE
+    libc_math_unittests
+  SRCS
+    scalbnf_test.cpp
+  HDRS
+    ScalbnTest.h
+  DEPENDS
+    libc.include.math
+    libc.src.math.scalbnf
+    libc.src.__support.FPUtil.fp_bits
+    libc.src.__support.FPUtil.normal_float
+)
+
+add_fp_unittest(
+  scalbnl_test
+  NEED_MPFR
+  SUITE
+    libc_math_unittests
+  SRCS
+    scalbnl_test.cpp
+  HDRS
+    ScalbnTest.h
+  DEPENDS
+    libc.include.math
+    libc.src.math.scalbnl
+    libc.src.__support.FPUtil.fp_bits
+    libc.src.__support.FPUtil.normal_float
 )
 
 add_subdirectory(generic)

diff  --git a/libc/test/src/math/ScalbnTest.h b/libc/test/src/math/ScalbnTest.h
new file mode 100644
index 0000000000000..8a078fc1e237d
--- /dev/null
+++ b/libc/test/src/math/ScalbnTest.h
@@ -0,0 +1,28 @@
+//===-- Utility class to test 
diff erent flavors of scalbn -------*- C++ -*-===//
+//
+// 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
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef LLVM_LIBC_TEST_SRC_MATH_SCALBN_H
+#define LLVM_LIBC_TEST_SRC_MATH_SCALBN_H
+
+#include "LdExpTest.h"
+#include "utils/UnitTest/Test.h"
+
+#define LIST_SCALBN_TESTS(T, func)                                             \
+  using LlvmLibcScalbnTest = LdExpTestTemplate<T>;                             \
+  TEST_F(LlvmLibcScalbnTest, SpecialNumbers) { testSpecialNumbers(&func); }    \
+  TEST_F(LlvmLibcScalbnTest, PowersOfTwo) { testPowersOfTwo(&func); }          \
+  TEST_F(LlvmLibcScalbnTest, OverFlow) { testOverflow(&func); }                \
+  TEST_F(LlvmLibcScalbnTest, UnderflowToZeroOnNormal) {                        \
+    testUnderflowToZeroOnNormal(&func);                                        \
+  }                                                                            \
+  TEST_F(LlvmLibcScalbnTest, UnderflowToZeroOnSubnormal) {                     \
+    testUnderflowToZeroOnSubnormal(&func);                                     \
+  }                                                                            \
+  TEST_F(LlvmLibcScalbnTest, NormalOperation) { testNormalOperation(&func); }
+
+#endif // LLVM_LIBC_TEST_SRC_MATH_SCALBN_H

diff  --git a/libc/test/src/math/scalbn_test.cpp b/libc/test/src/math/scalbn_test.cpp
new file mode 100644
index 0000000000000..d4d60bf8afca1
--- /dev/null
+++ b/libc/test/src/math/scalbn_test.cpp
@@ -0,0 +1,13 @@
+//===-- Unittests for scalbn ----------------------------------------------===//
+//
+// 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 "ScalbnTest.h"
+
+#include "src/math/scalbn.h"
+
+LIST_SCALBN_TESTS(double, __llvm_libc::scalbn)

diff  --git a/libc/test/src/math/scalbnf_test.cpp b/libc/test/src/math/scalbnf_test.cpp
new file mode 100644
index 0000000000000..cbf2e7e1361e1
--- /dev/null
+++ b/libc/test/src/math/scalbnf_test.cpp
@@ -0,0 +1,13 @@
+//===-- Unittests for scalbnf ---------------------------------------------===//
+//
+// 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 "ScalbnTest.h"
+
+#include "src/math/scalbnf.h"
+
+LIST_SCALBN_TESTS(float, __llvm_libc::scalbnf)

diff  --git a/libc/test/src/math/scalbnl_test.cpp b/libc/test/src/math/scalbnl_test.cpp
new file mode 100644
index 0000000000000..197887b2448c0
--- /dev/null
+++ b/libc/test/src/math/scalbnl_test.cpp
@@ -0,0 +1,13 @@
+//===-- Unittests for scalbnl ---------------------------------------------===//
+//
+// 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 "ScalbnTest.h"
+
+#include "src/math/scalbnl.h"
+
+LIST_SCALBN_TESTS(long double, __llvm_libc::scalbnl)


        


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