[libc-commits] [libc] [libc] Enables MPFR for float80 and adds tests for it (PR #223800)

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llvmorg-github-actions[bot] wrote:


<!--LLVM PR SUMMARY COMMENT-->

@llvm/pr-subscribers-libc

Author: Zorojuro (Sukumarsawant)

<details>
<summary>Changes</summary>

This temporarily only enables them where its natively avaialble i.e where long double is float80 (x86)

---
Full diff: https://github.com/llvm/llvm-project/pull/223800.diff


5 Files Affected:

- (modified) libc/test/src/__support/FPUtil/CMakeLists.txt (+1) 
- (modified) libc/test/src/__support/FPUtil/float80_test.cpp (+17) 
- (modified) libc/utils/MPFRWrapper/CMakeLists.txt (+1) 
- (modified) libc/utils/MPFRWrapper/MPCommon.cpp (+7) 
- (modified) libc/utils/MPFRWrapper/MPCommon.h (+14-3) 


``````````diff
diff --git a/libc/test/src/__support/FPUtil/CMakeLists.txt b/libc/test/src/__support/FPUtil/CMakeLists.txt
index b5d9ca2331697..994cc1fef4d0b 100644
--- a/libc/test/src/__support/FPUtil/CMakeLists.txt
+++ b/libc/test/src/__support/FPUtil/CMakeLists.txt
@@ -54,6 +54,7 @@ add_fp_unittest(
 
 add_fp_unittest(
   float80_test
+  NEED_MPFR
   SUITE
     libc-fputil-tests
   SRCS
diff --git a/libc/test/src/__support/FPUtil/float80_test.cpp b/libc/test/src/__support/FPUtil/float80_test.cpp
index c59be71240b9d..e9850caa219f2 100644
--- a/libc/test/src/__support/FPUtil/float80_test.cpp
+++ b/libc/test/src/__support/FPUtil/float80_test.cpp
@@ -11,6 +11,7 @@
 #include "src/__support/FPUtil/float80.h"
 #include "test/UnitTest/FPMatcher.h"
 #include "test/UnitTest/Test.h"
+#include "utils/MPFRWrapper/MPCommon.h"
 
 using LIBC_NAMESPACE::Sign;
 using LIBC_NAMESPACE::fputil::Float80;
@@ -134,6 +135,22 @@ TEST(LlvmLibcFloat80Test, randomTest) {
   }
 }
 
+TEST(LlvmLibcFloat80Test, MPFRConversion) {
+  using LIBC_NAMESPACE::testing::mpfr::MPFRNumber;
+
+  Float80 values[] = {
+      Float80(0.0f),  Float80(-0.0f),      Float80(1.0f),
+      Float80(-1.0f), Float80(2.0f),       Float80(0.5f),
+      Float80(100.0), Float80(12345.6789), Float80(1e10f),
+  };
+
+  for (Float80 val : values) {
+    MPFRNumber mpfr_val(val);
+    Float80 result = mpfr_val.as<Float80>();
+    EXPECT_TRUE(val == result);
+  }
+}
+
 #endif // LIBC_TYPES_LONG_DOUBLE_IS_X86_FLOAT80
 
 TEST(LlvmLibcFloat80Test, FromIntegralTypes) {
diff --git a/libc/utils/MPFRWrapper/CMakeLists.txt b/libc/utils/MPFRWrapper/CMakeLists.txt
index 8efa6fc1f0b12..53ad5ef4aa48c 100644
--- a/libc/utils/MPFRWrapper/CMakeLists.txt
+++ b/libc/utils/MPFRWrapper/CMakeLists.txt
@@ -16,6 +16,7 @@ if(LIBC_TESTS_CAN_USE_MPFR OR LIBC_TESTS_CAN_USE_MPC)
     libc.src.__support.CPP.type_traits
     libc.src.__support.FPUtil.bfloat16
     libc.src.__support.FPUtil.cast
+    libc.src.__support.FPUtil.float80
     libc.src.__support.FPUtil.fp_bits
     libc.test.UnitTest.FPTestHelpers
   )
diff --git a/libc/utils/MPFRWrapper/MPCommon.cpp b/libc/utils/MPFRWrapper/MPCommon.cpp
index 2422bcf45222f..2901bed391416 100644
--- a/libc/utils/MPFRWrapper/MPCommon.cpp
+++ b/libc/utils/MPFRWrapper/MPCommon.cpp
@@ -11,6 +11,7 @@
 #include "src/__support/CPP/string_view.h"
 #include "src/__support/FPUtil/bfloat16.h"
 #include "src/__support/FPUtil/cast.h"
+#include "src/__support/FPUtil/float80.h"
 #include "src/__support/macros/config.h"
 #include "src/__support/macros/properties/types.h"
 
@@ -646,6 +647,12 @@ template <> float128 MPFRNumber::as<float128>() const {
 }
 #endif // LIBC_TYPES_FLOAT128_IS_NOT_LONG_DOUBLE
 
+#ifdef LIBC_TYPES_LONG_DOUBLE_IS_X86_FLOAT80
+template <> float80 MPFRNumber::as<float80>() const {
+  return fputil::cast<float80>(mpfr_get_ld(value, mpfr_rounding));
+}
+#endif
+
 template <> bfloat16 MPFRNumber::as<bfloat16>() const {
   return fputil::cast<bfloat16>(mpfr_get_flt(value, mpfr_rounding));
 }
diff --git a/libc/utils/MPFRWrapper/MPCommon.h b/libc/utils/MPFRWrapper/MPCommon.h
index 38fd15fcc956c..07d1228724ccc 100644
--- a/libc/utils/MPFRWrapper/MPCommon.h
+++ b/libc/utils/MPFRWrapper/MPCommon.h
@@ -24,7 +24,7 @@ extern "C" {
 int mpfr_set_float128(mpfr_ptr, float128, mpfr_rnd_t);
 float128 mpfr_get_float128(mpfr_srcptr, mpfr_rnd_t);
 }
-#endif
+#endif // LIBC_TYPES_FLOAT128_IS_NOT_LONG_DOUBLE
 
 namespace LIBC_NAMESPACE_DECL {
 namespace testing {
@@ -41,7 +41,7 @@ template <typename T> struct ExtraPrecision;
 template <> struct ExtraPrecision<float16> {
   static constexpr unsigned int VALUE = 128;
 };
-#endif
+#endif // LIBC_TYPES_HAS_FLOAT16
 
 template <> struct ExtraPrecision<float> {
   static constexpr unsigned int VALUE = 128;
@@ -65,6 +65,12 @@ template <> struct ExtraPrecision<float128> {
 };
 #endif // LIBC_TYPES_FLOAT128_IS_NOT_LONG_DOUBLE
 
+#ifdef LIBC_TYPES_LONG_DOUBLE_IS_X86_FLOAT80
+template <> struct ExtraPrecision<float80> {
+  static constexpr unsigned int VALUE = 256;
+};
+#endif
+
 template <> struct ExtraPrecision<bfloat16> {
   static constexpr unsigned int VALUE = 64;
 };
@@ -139,7 +145,12 @@ class MPFRNumber {
   }
 
   template <typename XType,
-            cpp::enable_if_t<cpp::is_same_v<long double, XType>, int> = 0>
+            cpp::enable_if_t<cpp::is_same_v<long double, XType>
+#ifdef LIBC_TYPES_LONG_DOUBLE_IS_X86_FLOAT80
+                                 || cpp::is_same_v<float80, XType>
+#endif // LIBC_TYPES_LONG_DOUBLE_IS_X86_FLOAT80
+                             ,
+                             int> = 0>
   explicit MPFRNumber(XType x,
                       unsigned int precision = ExtraPrecision<XType>::VALUE,
                       RoundingMode rounding = RoundingMode::Nearest)

``````````

</details>


https://github.com/llvm/llvm-project/pull/223800