[libc-commits] [libc] [libc][math][c++23] Add Fmabf16 math function (PR #182836)

[Anton Shepelev via libc-commits]

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@@ -0,0 +1,69 @@
+//===-- Exhaustive test for fmabf16 ---------------------------------------===//
+//
+// 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/__support/FPUtil/bfloat16.h"
+#include "src/math/fmabf16.h"
+#include "test/UnitTest/FPMatcher.h"
+#include "test/UnitTest/Test.h"
+#include "utils/MPFRWrapper/MPFRUtils.h"
+
+using LlvmLibcFmaBf16Test = LIBC_NAMESPACE::testing::FPTest<bfloat16>;
+
+namespace mpfr = LIBC_NAMESPACE::testing::mpfr;
+
+// subnormal range (negative)
+static constexpr uint16_t SUBNORM_NEG_START = 0x8001U;
+static constexpr uint16_t SUBNORM_NEG_STOP = 0x807FU;
+
+TEST_F(LlvmLibcFmaBf16Test, SubnormalNegativeRange) {
+  constexpr bfloat16 Z_VALUES[] = {zero,    neg_zero,   inf,
+                                   neg_inf, min_normal, max_normal};
+  for (uint16_t v1 = SUBNORM_NEG_START; v1 <= SUBNORM_NEG_STOP; v1++) {
+    for (uint16_t v2 = SUBNORM_NEG_START; v2 <= SUBNORM_NEG_STOP; v2++) {
+
+      bfloat16 x = FPBits(v1).get_val();
+      bfloat16 y = FPBits(v2).get_val();
+      for (const bfloat16 &z : Z_VALUES) {
+        mpfr::TernaryInput<bfloat16> input{x, y, z};
+
+        EXPECT_MPFR_MATCH_ALL_ROUNDING(mpfr::Operation::Fma, input,
+                                       LIBC_NAMESPACE::fmabf16(x, y, z), 0.5);
+      }
+      bfloat16 neg_xy = -(x * y);
+      mpfr::TernaryInput<bfloat16> input{x, y, neg_xy};
+      EXPECT_MPFR_MATCH_ALL_ROUNDING(mpfr::Operation::Fma, input,
+                                     LIBC_NAMESPACE::fmabf16(x, y, neg_xy),
+                                     0.5);
+    }
+  }
+}
+
+TEST_F(LlvmLibcFmaBf16Test, SpecialNumbers) {
+  constexpr bfloat16 Z_VALUES[] = {zero,    neg_zero,   inf,
+                                   neg_inf, min_normal, max_normal};
+  constexpr bfloat16 X_VALUES[] = {zero,    neg_zero,   inf,
+                                   neg_inf, min_normal, max_normal};
+  constexpr bfloat16 Y_VALUES[] = {zero,    neg_zero,   inf,
+                                   neg_inf, min_normal, max_normal};
+
+  for (const bfloat16 &x : X_VALUES) {
+    for (const bfloat16 &y : Y_VALUES) {
+      for (const bfloat16 &z : Z_VALUES) {
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amemov wrote:

I think we have similar thing here 

https://github.com/llvm/llvm-project/pull/182836