diff --git a/blake2.cpp b/blake2.cpp
index 96dedfbc..9eb6997b 100644
--- a/blake2.cpp
+++ b/blake2.cpp
@@ -163,6 +163,8 @@ extern void BLAKE2_Compress64_NEON(const byte* input, BLAKE2b_State& state);
 #endif
 
 #if CRYPTOPP_ALTIVEC_AVAILABLE
+// BLAKE2_Compress32_POWER7 may be compiled with either -mcpu=power7 or
+// -mcpu=power4. The makefile drops to POWER4 if POWER7 is not available.
 extern void BLAKE2_Compress32_POWER7(const byte* input, BLAKE2s_State& state);
 #endif
 
@@ -390,8 +392,7 @@ std::string BLAKE2s::AlgorithmProvider() const
 #if (CRYPTOPP_POWER7_AVAILABLE)
     if (HasPower7())
         return "Power7";
-#endif
-#if (CRYPTOPP_ALTIVEC_AVAILABLE)
+#elif (CRYPTOPP_ALTIVEC_AVAILABLE)
     if (HasAltivec())
         return "Altivec";
 #endif
@@ -666,9 +667,16 @@ void BLAKE2s::Compress(const byte *input)
         return BLAKE2_Compress32_NEON(input, *m_state.data());
     }
 #endif
-#if CRYPTOPP_ALTIVEC_AVAILABLE
+#if CRYPTOPP_POWER7_AVAILABLE
+    if(HasPower7())
+    {
+		// BLAKE2_Compress32_POWER7 compiled with -mcpu=power7 and -DCRYPTOPP_POWER7_AVAILABLE
+        return BLAKE2_Compress32_POWER7(input, *m_state.data());
+    }
+#elif CRYPTOPP_ALTIVEC_AVAILABLE
     if(HasAltivec())
     {
+		// BLAKE2_Compress32_POWER7 compiled with -mcpu=power4 and -DCRYPTOPP_ALTIVEC_AVAILABLE
         return BLAKE2_Compress32_POWER7(input, *m_state.data());
     }
 #endif