crypto: Guard code with ENABLE_SSE41 macro

The code in `sha_x86_shani.cpp` uses the `_mm_blend_epi16` function from
the SSE4.1 instruction set. However, it is possible that SHA-NI is
enabled even when SSE4.1 is disabled.

This changes avoid compilation errors in such a condition.

Author: hebasto

src/Makefile.am

@@ -53,15 +53,15 @@ LIBBITCOIN_CRYPTO = $(LIBBITCOIN_CRYPTO_BASE)
 if ENABLE_SSE41
 LIBBITCOIN_CRYPTO_SSE41 = crypto/libbitcoin_crypto_sse41.la
 LIBBITCOIN_CRYPTO += $(LIBBITCOIN_CRYPTO_SSE41)
+if ENABLE_X86_SHANI
+LIBBITCOIN_CRYPTO_X86_SHANI = crypto/libbitcoin_crypto_x86_shani.la
+LIBBITCOIN_CRYPTO += $(LIBBITCOIN_CRYPTO_X86_SHANI)
+endif
 endif
 if ENABLE_AVX2
 LIBBITCOIN_CRYPTO_AVX2 = crypto/libbitcoin_crypto_avx2.la
 LIBBITCOIN_CRYPTO += $(LIBBITCOIN_CRYPTO_AVX2)
 endif
-if ENABLE_X86_SHANI
-LIBBITCOIN_CRYPTO_X86_SHANI = crypto/libbitcoin_crypto_x86_shani.la
-LIBBITCOIN_CRYPTO += $(LIBBITCOIN_CRYPTO_X86_SHANI)
-endif
 if ENABLE_ARM_SHANI
 LIBBITCOIN_CRYPTO_ARM_SHANI = crypto/libbitcoin_crypto_arm_shani.la
 LIBBITCOIN_CRYPTO += $(LIBBITCOIN_CRYPTO_ARM_SHANI)
@@ -612,7 +612,7 @@ crypto_libbitcoin_crypto_x86_shani_la_LDFLAGS = $(AM_LDFLAGS) -static
 crypto_libbitcoin_crypto_x86_shani_la_CXXFLAGS = $(AM_CXXFLAGS) $(PIE_FLAGS) -static
 crypto_libbitcoin_crypto_x86_shani_la_CPPFLAGS = $(AM_CPPFLAGS)
 crypto_libbitcoin_crypto_x86_shani_la_CXXFLAGS += $(X86_SHANI_CXXFLAGS)
-crypto_libbitcoin_crypto_x86_shani_la_CPPFLAGS += -DENABLE_X86_SHANI
+crypto_libbitcoin_crypto_x86_shani_la_CPPFLAGS += -DENABLE_SSE41 -DENABLE_X86_SHANI
 crypto_libbitcoin_crypto_x86_shani_la_SOURCES = crypto/sha256_x86_shani.cpp
 
 # See explanation for -static in crypto_libbitcoin_crypto_base_la's LDFLAGS and

src/crypto/sha256.cpp

@@ -623,7 +623,7 @@ std::string SHA256AutoDetect(sha256_implementation::UseImplementation use_implem
         }
     }
 
-#if defined(ENABLE_X86_SHANI)
+#if defined(ENABLE_SSE41) && defined(ENABLE_X86_SHANI)
     if (have_x86_shani) {
         Transform = sha256_x86_shani::Transform;
         TransformD64 = TransformD64Wrapper<sha256_x86_shani::Transform>;

src/crypto/sha256_x86_shani.cpp

@@ -6,7 +6,7 @@
 // Written and placed in public domain by Jeffrey Walton.
 // Based on code from Intel, and by Sean Gulley for the miTLS project.
 
-#ifdef ENABLE_X86_SHANI
+#if defined(ENABLE_SSE41) && defined(ENABLE_X86_SHANI)
 
 #include <stdint.h>
 #include <immintrin.h>