From c6efc4e0ba4b9acb8f99e6e976d4853bedc21db5 Mon Sep 17 00:00:00 2001
From: Antonio Sanchez <cantonios@google.com>
Date: Fri, 11 Dec 2020 14:34:31 -0800
Subject: Replace M_LOG2E and M_LN2 with custom macros.

For these to exist we would need to define `_USE_MATH_DEFINES` before
`cmath` or `math.h` is first included.  However, we don't
control the include order for projects outside Eigen, so even defining
the macro in `Eigen/Core` does not fix the issue for projects that
end up including `<cmath>` before Eigen does (explicitly or transitively).

To fix this, we define `EIGEN_LOG2E` and `EIGEN_LN2` ourselves.
---
 Eigen/src/Core/arch/Default/BFloat16.h                   | 2 +-
 Eigen/src/Core/arch/Default/GenericPacketMathFunctions.h | 8 ++++----
 Eigen/src/Core/arch/Default/Half.h                       | 2 +-
 3 files changed, 6 insertions(+), 6 deletions(-)

(limited to 'Eigen/src/Core/arch/Default')

diff --git a/Eigen/src/Core/arch/Default/BFloat16.h b/Eigen/src/Core/arch/Default/BFloat16.h
index 616dcf667..72a489b0b 100644
--- a/Eigen/src/Core/arch/Default/BFloat16.h
+++ b/Eigen/src/Core/arch/Default/BFloat16.h
@@ -513,7 +513,7 @@ EIGEN_STRONG_INLINE EIGEN_DEVICE_FUNC bfloat16 log10(const bfloat16& a) {
   return bfloat16(::log10f(float(a)));
 }
 EIGEN_STRONG_INLINE EIGEN_DEVICE_FUNC bfloat16 log2(const bfloat16& a) {
-  return bfloat16(static_cast<float>(M_LOG2E) * ::logf(float(a)));
+  return bfloat16(static_cast<float>(EIGEN_LOG2E) * ::logf(float(a)));
 }
 EIGEN_STRONG_INLINE EIGEN_DEVICE_FUNC bfloat16 sqrt(const bfloat16& a) {
     return bfloat16(::sqrtf(float(a)));
diff --git a/Eigen/src/Core/arch/Default/GenericPacketMathFunctions.h b/Eigen/src/Core/arch/Default/GenericPacketMathFunctions.h
index 45cc780f1..34e2cb1e7 100644
--- a/Eigen/src/Core/arch/Default/GenericPacketMathFunctions.h
+++ b/Eigen/src/Core/arch/Default/GenericPacketMathFunctions.h
@@ -132,10 +132,10 @@ Packet plog_impl_float(const Packet _x)
 
   // Add the logarithm of the exponent back to the result of the interpolation.
   if (base2) {
-    const Packet cst_log2e = pset1<Packet>(static_cast<float>(M_LOG2E));
+    const Packet cst_log2e = pset1<Packet>(static_cast<float>(EIGEN_LOG2E));
     x = pmadd(x, cst_log2e, e);
   } else {
-    const Packet cst_ln2 = pset1<Packet>(static_cast<float>(M_LN2));
+    const Packet cst_ln2 = pset1<Packet>(static_cast<float>(EIGEN_LN2));
     x = pmadd(e, cst_ln2, x);
   }
 
@@ -253,10 +253,10 @@ Packet plog_impl_double(const Packet _x)
 
   // Add the logarithm of the exponent back to the result of the interpolation.
   if (base2) {
-    const Packet cst_log2e = pset1<Packet>(M_LOG2E);
+    const Packet cst_log2e = pset1<Packet>(EIGEN_LOG2E);
     x = pmadd(x, cst_log2e, e);
   } else {
-    const Packet cst_ln2 = pset1<Packet>(M_LN2);
+    const Packet cst_ln2 = pset1<Packet>(EIGEN_LN2);
     x = pmadd(e, cst_ln2, x);
   }
 
diff --git a/Eigen/src/Core/arch/Default/Half.h b/Eigen/src/Core/arch/Default/Half.h
index 204076e25..54fd86aa7 100644
--- a/Eigen/src/Core/arch/Default/Half.h
+++ b/Eigen/src/Core/arch/Default/Half.h
@@ -623,7 +623,7 @@ EIGEN_STRONG_INLINE EIGEN_DEVICE_FUNC half log10(const half& a) {
   return half(::log10f(float(a)));
 }
 EIGEN_STRONG_INLINE EIGEN_DEVICE_FUNC half log2(const half& a) {
-  return half(static_cast<float>(M_LOG2E) * ::logf(float(a)));
+  return half(static_cast<float>(EIGEN_LOG2E) * ::logf(float(a)));
 }
 
 EIGEN_STRONG_INLINE EIGEN_DEVICE_FUNC half sqrt(const half& a) {
-- 
cgit v1.2.3