From 63a40ffb951a8f6b7662d14c6613c5c2994a9b61 Mon Sep 17 00:00:00 2001
From: Rasmus Munk Larsen <rmlarsen@google.com>
Date: Fri, 28 Mar 2025 04:26:04 +0000
Subject: [PATCH] Use fma<float> for fma<half> and fma<bfloat16> if native fma
 is not available on the platform.

---
 Eigen/src/Core/arch/Default/BFloat16.h | 2 +-
 Eigen/src/Core/arch/Default/Half.h     | 2 +-
 2 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/Eigen/src/Core/arch/Default/BFloat16.h b/Eigen/src/Core/arch/Default/BFloat16.h
index 110a07d46..f2e55f345 100644
--- a/Eigen/src/Core/arch/Default/BFloat16.h
+++ b/Eigen/src/Core/arch/Default/BFloat16.h
@@ -675,7 +675,7 @@ EIGEN_STRONG_INLINE EIGEN_DEVICE_FUNC bfloat16 fmax(const bfloat16& a, const bfl
 
 EIGEN_DEVICE_FUNC inline bfloat16 fma(const bfloat16& a, const bfloat16& b, const bfloat16& c) {
   // Emulate FMA via float.
-  return bfloat16(static_cast<float>(a) * static_cast<float>(b) + static_cast<float>(c));
+  return bfloat16(numext::fma(static_cast<float>(a), static_cast<float>(b), static_cast<float>(c)));
 }
 
 #ifndef EIGEN_NO_IO
diff --git a/Eigen/src/Core/arch/Default/Half.h b/Eigen/src/Core/arch/Default/Half.h
index af0d17266..ba70d5fab 100644
--- a/Eigen/src/Core/arch/Default/Half.h
+++ b/Eigen/src/Core/arch/Default/Half.h
@@ -812,7 +812,7 @@ EIGEN_DEVICE_FUNC inline half fma(const half& a, const half& b, const half& c) {
   return half(_mm_cvtsh_h(_mm_fmadd_ph(_mm_set_sh(a.x), _mm_set_sh(b.x), _mm_set_sh(c.x))));
 #else
   // Emulate FMA via float.
-  return half(static_cast<float>(a) * static_cast<float>(b) + static_cast<float>(c));
+  return half(numext::fma(static_cast<float>(a), static_cast<float>(b), static_cast<float>(c)));
 #endif
 }