diff --git a/Eigen/src/Core/arch/AltiVec/Complex.h b/Eigen/src/Core/arch/AltiVec/Complex.h
index 46812f97b..60f28ff70 100644
--- a/Eigen/src/Core/arch/AltiVec/Complex.h
+++ b/Eigen/src/Core/arch/AltiVec/Complex.h
@@ -18,7 +18,7 @@ namespace Eigen {
 namespace internal {
 
 static Packet4ui  p4ui_CONJ_XOR = vec_mergeh((Packet4ui)p4i_ZERO, (Packet4ui)p4f_MZERO);//{ 0x00000000, 0x80000000, 0x00000000, 0x80000000 };
-#ifdef __VSX__
+#ifdef EIGEN_VECTORIZE_VSX
 #if defined(_BIG_ENDIAN)
 static Packet2ul  p2ul_CONJ_XOR1 = (Packet2ul) vec_sld((Packet4ui) p2d_MZERO, (Packet4ui) p2l_ZERO, 8);//{ 0x8000000000000000, 0x0000000000000000 };
 static Packet2ul  p2ul_CONJ_XOR2 = (Packet2ul) vec_sld((Packet4ui) p2l_ZERO,  (Packet4ui) p2d_MZERO, 8);//{ 0x8000000000000000, 0x0000000000000000 };
@@ -103,7 +103,7 @@ template<> struct packet_traits<std::complex<float> >  : default_packet_traits
     HasMin    = 0,
     HasMax    = 0,
     HasSqrt   = 1,
-#ifdef __VSX__
+#ifdef EIGEN_VECTORIZE_VSX
     HasBlend  = 1,
 #endif
     HasSetLinear = 0
@@ -115,7 +115,7 @@ template<> struct unpacket_traits<Packet2cf> { typedef std::complex<float> type;
 template<> EIGEN_STRONG_INLINE Packet2cf pset1<Packet2cf>(const std::complex<float>&  from)
 {
   Packet2cf res;
-#ifdef __VSX__
+#ifdef EIGEN_VECTORIZE_VSX
   // Load a single std::complex<float> from memory and duplicate
   //
   // Using pload would read past the end of the reference in this case
@@ -151,7 +151,7 @@ template<> EIGEN_ALWAYS_INLINE void pstoreu_partial<std::complex<float> >(std::c
 EIGEN_STRONG_INLINE Packet2cf pload2(const std::complex<float>& from0, const std::complex<float>& from1)
 {
   Packet4f res0, res1;
-#ifdef __VSX__
+#ifdef EIGEN_VECTORIZE_VSX
   // Load two std::complex<float> from memory and combine
   __asm__ ("lxsdx %x0,%y1" : "=wa" (res0) : "Z" (from0));
   __asm__ ("lxsdx %x0,%y1" : "=wa" (res1) : "Z" (from1));
@@ -269,7 +269,7 @@ template<> EIGEN_STRONG_INLINE Packet2cf pcplxflip<Packet2cf>(const Packet2cf& x
 
 EIGEN_STRONG_INLINE void ptranspose(PacketBlock<Packet2cf,2>& kernel)
 {
-#ifdef __VSX__
+#ifdef EIGEN_VECTORIZE_VSX
   Packet4f tmp = reinterpret_cast<Packet4f>(vec_mergeh(reinterpret_cast<Packet2d>(kernel.packet[0].v), reinterpret_cast<Packet2d>(kernel.packet[1].v)));
   kernel.packet[1].v = reinterpret_cast<Packet4f>(vec_mergel(reinterpret_cast<Packet2d>(kernel.packet[0].v), reinterpret_cast<Packet2d>(kernel.packet[1].v)));
 #else
@@ -284,7 +284,7 @@ template<> EIGEN_STRONG_INLINE Packet2cf pcmp_eq(const Packet2cf& a, const Packe
   return Packet2cf(vec_and(eq, vec_perm(eq, eq, p16uc_COMPLEX32_REV)));
 }
 
-#ifdef __VSX__
+#ifdef EIGEN_VECTORIZE_VSX
 template<> EIGEN_STRONG_INLINE Packet2cf pblend(const Selector<2>& ifPacket, const Packet2cf& thenPacket, const Packet2cf& elsePacket) {
   Packet2cf result;
   result.v = reinterpret_cast<Packet4f>(pblend<Packet2d>(ifPacket, reinterpret_cast<Packet2d>(thenPacket.v), reinterpret_cast<Packet2d>(elsePacket.v)));
@@ -298,7 +298,7 @@ template<> EIGEN_STRONG_INLINE Packet2cf psqrt<Packet2cf>(const Packet2cf& a)
 }
 
 //---------- double ----------
-#ifdef __VSX__
+#ifdef EIGEN_VECTORIZE_VSX
 struct Packet1cd
 {
   EIGEN_STRONG_INLINE Packet1cd() {}
diff --git a/Eigen/src/Core/arch/AltiVec/MathFunctions.h b/Eigen/src/Core/arch/AltiVec/MathFunctions.h
index 6f48d98fb..bda3722da 100644
--- a/Eigen/src/Core/arch/AltiVec/MathFunctions.h
+++ b/Eigen/src/Core/arch/AltiVec/MathFunctions.h
@@ -60,7 +60,7 @@ Packet4f patan<Packet4f>(const Packet4f& _x)
   return patan_float(_x);
 }
 
-#ifdef __VSX__
+#ifdef EIGEN_VECTORIZE_VSX
 #ifndef EIGEN_COMP_CLANG
 template<> EIGEN_DEFINE_FUNCTION_ALLOWING_MULTIPLE_DEFINITIONS
 Packet4f prsqrt<Packet4f>(const Packet4f& x)
diff --git a/Eigen/src/Core/arch/AltiVec/MatrixVectorProduct.h b/Eigen/src/Core/arch/AltiVec/MatrixVectorProduct.h
index 9d00b93e4..bb84ac977 100644
--- a/Eigen/src/Core/arch/AltiVec/MatrixVectorProduct.h
+++ b/Eigen/src/Core/arch/AltiVec/MatrixVectorProduct.h
@@ -599,7 +599,7 @@ EIGEN_ALWAYS_INLINE Packet2cf pcplxflip2(Packet2cf a)
 
 EIGEN_ALWAYS_INLINE Packet1cd pcplxflip2(Packet1cd a)
 {
-#ifdef __VSX__
+#ifdef EIGEN_VECTORIZE_VSX
     return Packet1cd(__builtin_vsx_xxpermdi(a.v, a.v, 2));
 #else
     return Packet1cd(Packet2d(vec_perm(Packet16uc(a.v), Packet16uc(a.v), p16uc_COMPLEX64_XORFLIP)));
@@ -610,7 +610,7 @@ EIGEN_ALWAYS_INLINE Packet1cd pcplxflip2(Packet1cd a)
 EIGEN_ALWAYS_INLINE Packet4f pload_complex_half(std::complex<float>* src)
 {
     Packet4f t;
-#ifdef __VSX__
+#ifdef EIGEN_VECTORIZE_VSX
     // Load float64/two float32 (doubleword alignment)
     __asm__("lxsdx %x0,%y1" : "=wa" (t) : "Z" (*src));
 #else
@@ -636,7 +636,7 @@ EIGEN_ALWAYS_INLINE void pload_realimag(RhsScalar* src, Packet4f& r, Packet4f& i
 template<typename RhsScalar>
 EIGEN_ALWAYS_INLINE void pload_realimag(RhsScalar* src, Packet2d& r, Packet2d& i)
 {
-#ifdef __VSX__
+#ifdef EIGEN_VECTORIZE_VSX
     __asm__("lxvdsx %x0,%y1" : "=wa" (r) : "Z" (*(reinterpret_cast<double*>(src) + 0)));
     __asm__("lxvdsx %x0,%y1" : "=wa" (i) : "Z" (*(reinterpret_cast<double*>(src) + 1)));
 #else
@@ -675,7 +675,7 @@ EIGEN_ALWAYS_INLINE void pload_realimag_row(RhsScalar* src, Packet2d& r, Packet2
 /** \internal load and splat a complex value into a vector - column-wise */
 EIGEN_ALWAYS_INLINE Packet4f pload_realimag_combine(std::complex<float>* src)
 {
-#ifdef __VSX__
+#ifdef EIGEN_VECTORIZE_VSX
     Packet4f ret;
     __asm__("lxvdsx %x0,%y1" : "=wa" (ret) : "Z" (*(reinterpret_cast<double*>(src) + 0)));
     return ret;
diff --git a/Eigen/src/Core/arch/AltiVec/PacketMath.h b/Eigen/src/Core/arch/AltiVec/PacketMath.h
index b0f85294e..86532a087 100644
--- a/Eigen/src/Core/arch/AltiVec/PacketMath.h
+++ b/Eigen/src/Core/arch/AltiVec/PacketMath.h
@@ -173,7 +173,7 @@ struct packet_traits<float> : default_packet_traits {
     HasATan = 1,
     HasLog = 1,
     HasExp = 1,
-#ifdef __VSX__
+#ifdef EIGEN_VECTORIZE_VSX
     HasSqrt = 1,
 #if !EIGEN_COMP_CLANG
     HasRsqrt = 1,
@@ -218,7 +218,7 @@ struct packet_traits<bfloat16> : default_packet_traits {
     HasCos = EIGEN_FAST_MATH,
     HasLog = 1,
     HasExp = 1,
-#ifdef __VSX__
+#ifdef EIGEN_VECTORIZE_VSX
     HasSqrt = 1,
 #if !EIGEN_COMP_CLANG
     HasRsqrt = 1,
@@ -446,7 +446,7 @@ EIGEN_STRONG_INLINE Packet pload_common(const __UNPACK_TYPE__(Packet)* from)
   // ignoring these warnings for now.
   EIGEN_UNUSED_VARIABLE(from);
   EIGEN_DEBUG_ALIGNED_LOAD
-#ifdef __VSX__
+#ifdef EIGEN_VECTORIZE_VSX
   return vec_xl(0, const_cast<__UNPACK_TYPE__(Packet)*>(from));
 #else
   return vec_ld(0, from);
@@ -501,7 +501,7 @@ EIGEN_ALWAYS_INLINE Packet pload_ignore(const __UNPACK_TYPE__(Packet)* from)
   #pragma GCC diagnostic push
   #pragma GCC diagnostic ignored "-Wmaybe-uninitialized"
 #endif
-#ifdef __VSX__
+#ifdef EIGEN_VECTORIZE_VSX
   return vec_xl(0, const_cast<__UNPACK_TYPE__(Packet)*>(from));
 #else
   return vec_ld(0, from);
@@ -608,7 +608,7 @@ EIGEN_STRONG_INLINE void pstore_common(__UNPACK_TYPE__(Packet)* to, const Packet
   // ignoring these warnings for now.
   EIGEN_UNUSED_VARIABLE(to);
   EIGEN_DEBUG_ALIGNED_STORE
-#ifdef __VSX__
+#ifdef EIGEN_VECTORIZE_VSX
   vec_xst(from, 0, to);
 #else
   vec_st(from, 0, to);
@@ -1054,7 +1054,7 @@ template<> EIGEN_STRONG_INLINE Packet4i pmadd(const Packet4i& a, const Packet4i&
 template<> EIGEN_STRONG_INLINE Packet8s pmadd(const Packet8s& a, const Packet8s& b, const Packet8s& c) { return vec_madd(a,b,c); }
 template<> EIGEN_STRONG_INLINE Packet8us pmadd(const Packet8us& a, const Packet8us& b, const Packet8us& c) { return vec_madd(a,b,c); }
 
-#ifdef __VSX__
+#ifdef EIGEN_VECTORIZE_VSX
 template<> EIGEN_STRONG_INLINE Packet4f pmsub(const Packet4f& a, const Packet4f& b, const Packet4f& c) { return vec_msub(a,b,c); }
 template<> EIGEN_STRONG_INLINE Packet4f pnmadd(const Packet4f& a, const Packet4f& b, const Packet4f& c) { return vec_nmsub(a,b,c); }
 template<> EIGEN_STRONG_INLINE Packet4f pnmsub(const Packet4f& a, const Packet4f& b, const Packet4f& c) { return vec_nmadd(a,b,c); }
@@ -1062,7 +1062,7 @@ template<> EIGEN_STRONG_INLINE Packet4f pnmsub(const Packet4f& a, const Packet4f
 
 template<> EIGEN_STRONG_INLINE Packet4f pmin<Packet4f>(const Packet4f& a, const Packet4f& b)
 {
-  #ifdef __VSX__
+  #ifdef EIGEN_VECTORIZE_VSX
   // NOTE: about 10% slower than vec_min, but consistent with std::min and SSE regarding NaN
   Packet4f ret;
   __asm__ ("xvcmpgesp %x0,%x1,%x2\n\txxsel %x0,%x1,%x2,%x0" : "=&wa" (ret) : "wa" (a), "wa" (b));
@@ -1080,7 +1080,7 @@ template<> EIGEN_STRONG_INLINE Packet16uc pmin<Packet16uc>(const Packet16uc& a,
 
 template<> EIGEN_STRONG_INLINE Packet4f pmax<Packet4f>(const Packet4f& a, const Packet4f& b)
 {
-  #ifdef __VSX__
+  #ifdef EIGEN_VECTORIZE_VSX
   // NOTE: about 10% slower than vec_max, but consistent with std::max and SSE regarding NaN
   Packet4f ret;
   __asm__ ("xvcmpgtsp %x0,%x2,%x1\n\txxsel %x0,%x1,%x2,%x0" : "=&wa" (ret) : "wa" (a), "wa" (b));
@@ -1103,27 +1103,27 @@ template<> EIGEN_STRONG_INLINE Packet4f pcmp_lt_or_nan(const Packet4f& a, const
   return vec_nor(c,c);
 }
 
-#ifdef __VSX__
+#ifdef EIGEN_VECTORIZE_VSX
 template<> EIGEN_STRONG_INLINE Packet4i pcmp_le(const Packet4i& a, const Packet4i& b) { return reinterpret_cast<Packet4i>(vec_cmple(a,b)); }
 #endif
 template<> EIGEN_STRONG_INLINE Packet4i pcmp_lt(const Packet4i& a, const Packet4i& b) { return reinterpret_cast<Packet4i>(vec_cmplt(a,b)); }
 template<> EIGEN_STRONG_INLINE Packet4i pcmp_eq(const Packet4i& a, const Packet4i& b) { return reinterpret_cast<Packet4i>(vec_cmpeq(a,b)); }
-#ifdef __VSX__
+#ifdef EIGEN_VECTORIZE_VSX
 template<> EIGEN_STRONG_INLINE Packet8s pcmp_le(const Packet8s& a, const Packet8s& b) { return reinterpret_cast<Packet8s>(vec_cmple(a,b)); }
 #endif
 template<> EIGEN_STRONG_INLINE Packet8s pcmp_lt(const Packet8s& a, const Packet8s& b) { return reinterpret_cast<Packet8s>(vec_cmplt(a,b)); }
 template<> EIGEN_STRONG_INLINE Packet8s pcmp_eq(const Packet8s& a, const Packet8s& b) { return reinterpret_cast<Packet8s>(vec_cmpeq(a,b)); }
-#ifdef __VSX__
+#ifdef EIGEN_VECTORIZE_VSX
 template<> EIGEN_STRONG_INLINE Packet8us pcmp_le(const Packet8us& a, const Packet8us& b) { return reinterpret_cast<Packet8us>(vec_cmple(a,b)); }
 #endif
 template<> EIGEN_STRONG_INLINE Packet8us pcmp_lt(const Packet8us& a, const Packet8us& b) { return reinterpret_cast<Packet8us>(vec_cmplt(a,b)); }
 template<> EIGEN_STRONG_INLINE Packet8us pcmp_eq(const Packet8us& a, const Packet8us& b) { return reinterpret_cast<Packet8us>(vec_cmpeq(a,b)); }
-#ifdef __VSX__
+#ifdef EIGEN_VECTORIZE_VSX
 template<> EIGEN_STRONG_INLINE Packet16c pcmp_le(const Packet16c& a, const Packet16c& b) { return reinterpret_cast<Packet16c>(vec_cmple(a,b)); }
 #endif
 template<> EIGEN_STRONG_INLINE Packet16c pcmp_lt(const Packet16c& a, const Packet16c& b) { return reinterpret_cast<Packet16c>(vec_cmplt(a,b)); }
 template<> EIGEN_STRONG_INLINE Packet16c pcmp_eq(const Packet16c& a, const Packet16c& b) { return reinterpret_cast<Packet16c>(vec_cmpeq(a,b)); }
-#ifdef __VSX__
+#ifdef EIGEN_VECTORIZE_VSX
 template<> EIGEN_STRONG_INLINE Packet16uc pcmp_le(const Packet16uc& a, const Packet16uc& b) { return reinterpret_cast<Packet16uc>(vec_cmple(a,b)); }
 #endif
 template<> EIGEN_STRONG_INLINE Packet16uc pcmp_lt(const Packet16uc& a, const Packet16uc& b) { return reinterpret_cast<Packet16uc>(vec_cmplt(a,b)); }
@@ -1164,7 +1164,7 @@ template<> EIGEN_STRONG_INLINE Packet4f pround<Packet4f>(const Packet4f& a)
     Packet4f t = vec_add(reinterpret_cast<Packet4f>(vec_or(vec_and(reinterpret_cast<Packet4ui>(a), p4ui_SIGN), p4ui_PREV0DOT5)), a);
     Packet4f res;
 
-#ifdef __VSX__
+#ifdef EIGEN_VECTORIZE_VSX
     __asm__("xvrspiz %x0, %x1\n\t"
         : "=&wa" (res)
         : "wa" (t));
@@ -1178,7 +1178,7 @@ template<> EIGEN_STRONG_INLINE Packet4f pround<Packet4f>(const Packet4f& a)
 }
 template<> EIGEN_STRONG_INLINE Packet4f pceil<Packet4f>(const  Packet4f& a) { return vec_ceil(a); }
 template<> EIGEN_STRONG_INLINE Packet4f pfloor<Packet4f>(const Packet4f& a) { return vec_floor(a); }
-#ifdef __VSX__
+#ifdef EIGEN_VECTORIZE_VSX
 template<> EIGEN_STRONG_INLINE Packet4f print<Packet4f>(const Packet4f& a)
 {
     Packet4f res;
@@ -1194,7 +1194,7 @@ template<> EIGEN_STRONG_INLINE Packet4f print<Packet4f>(const Packet4f& a)
 template<typename Packet> EIGEN_STRONG_INLINE Packet ploadu_common(const __UNPACK_TYPE__(Packet)* from)
 {
   EIGEN_DEBUG_ALIGNED_LOAD
-#if defined(__VSX__) || !defined(_BIG_ENDIAN)
+#if defined(EIGEN_VECTORIZE_VSX) || !defined(_BIG_ENDIAN)
   EIGEN_DEBUG_UNALIGNED_LOAD
   return vec_xl(0, const_cast<__UNPACK_TYPE__(Packet)*>(from));
 #else
@@ -1377,7 +1377,7 @@ template<> EIGEN_STRONG_INLINE Packet16uc ploaddup<Packet16uc>(const unsigned ch
 template<typename Packet> EIGEN_STRONG_INLINE void pstoreu_common(__UNPACK_TYPE__(Packet)*  to, const Packet& from)
 {
   EIGEN_DEBUG_UNALIGNED_STORE
-#if defined(__VSX__) || !defined(_BIG_ENDIAN)
+#if defined(EIGEN_VECTORIZE_VSX) || !defined(_BIG_ENDIAN)
   vec_xst(from, 0, to);
 #else
   // Taken from http://developer.apple.com/hardwaredrivers/ve/alignment.html
@@ -1773,7 +1773,7 @@ template<> EIGEN_STRONG_INLINE Packet8bf pceil<Packet8bf> (const Packet8bf& a){
 template<> EIGEN_STRONG_INLINE Packet8bf pround<Packet8bf> (const Packet8bf& a){
   BF16_TO_F32_UNARY_OP_WRAPPER(pround<Packet4f>, a);
 }
-#ifdef __VSX__
+#ifdef EIGEN_VECTORIZE_VSX
 template<> EIGEN_STRONG_INLINE Packet8bf print<Packet8bf> (const Packet8bf& a){
   BF16_TO_F32_UNARY_OP_WRAPPER(print<Packet4f>, a);
 }
@@ -2657,7 +2657,7 @@ template<> EIGEN_STRONG_INLINE Packet4f preinterpret<Packet4f,Packet4i>(const Pa
 
 
 //---------- double ----------
-#ifdef __VSX__
+#ifdef EIGEN_VECTORIZE_VSX
 typedef __vector double              Packet2d;
 typedef __vector unsigned long long  Packet2ul;
 typedef __vector long long           Packet2l;
diff --git a/Eigen/src/Core/util/ConfigureVectorization.h b/Eigen/src/Core/util/ConfigureVectorization.h
index 7c1a08bdc..b49fc01c3 100644
--- a/Eigen/src/Core/util/ConfigureVectorization.h
+++ b/Eigen/src/Core/util/ConfigureVectorization.h
@@ -352,10 +352,10 @@
       #endif
     } // end extern "C"
 
-  #elif defined __VSX__
+  #elif defined(__VSX__) && !defined(__APPLE__)
 
     #define EIGEN_VECTORIZE
-    #define EIGEN_VECTORIZE_VSX
+    #define EIGEN_VECTORIZE_VSX 1
     #include <altivec.h>
     // We need to #undef all these ugly tokens defined in <altivec.h>
     // => use __vector instead of vector
diff --git a/Eigen/src/Core/util/Macros.h b/Eigen/src/Core/util/Macros.h
index 344815943..c3804b376 100644
--- a/Eigen/src/Core/util/Macros.h
+++ b/Eigen/src/Core/util/Macros.h
@@ -371,7 +371,7 @@
 #endif
 
 /// \internal EIGEN_ARCH_PPC set to 1 if the architecture is PowerPC
-#if defined(__powerpc__) || defined(__ppc__) || defined(_M_PPC)
+#if defined(__powerpc__) || defined(__ppc__) || defined(_M_PPC) || defined(__POWERPC__)
   #define EIGEN_ARCH_PPC 1
 #else
   #define EIGEN_ARCH_PPC 0
@@ -976,11 +976,16 @@ namespace Eigen {
     // directly for std::complex<T>, Eigen::half, Eigen::bfloat16. For these,
     // you will need to apply to the underlying POD type.
     #if EIGEN_ARCH_PPC && EIGEN_COMP_GNUC_STRICT
-      // This seems to be broken on clang.  Packet4f is loaded into a single
-      //   register rather than a vector, zeroing out some entries.  Integer
+      // This seems to be broken on clang. Packet4f is loaded into a single
+      //   register rather than a vector, zeroing out some entries. Integer
       //   types also generate a compile error.
-      // General, Altivec, VSX.
-      #define EIGEN_OPTIMIZATION_BARRIER(X)  __asm__  ("" : "+r,v,wa" (X));
+      #if EIGEN_OS_MAC
+        // General, Altivec for Apple (VSX were added in ISA v2.06):
+        #define EIGEN_OPTIMIZATION_BARRIER(X)  __asm__  ("" : "+r,v" (X));
+      #else
+        // General, Altivec, VSX otherwise:
+        #define EIGEN_OPTIMIZATION_BARRIER(X)  __asm__  ("" : "+r,v,wa" (X));
+      #endif
     #elif EIGEN_ARCH_ARM_OR_ARM64
       #ifdef __ARM_FP
         // General, VFP or NEON.