diff --git a/GNUmakefile b/GNUmakefile
index b2046669..d93ff4be 100644
--- a/GNUmakefile
+++ b/GNUmakefile
@@ -23,32 +23,30 @@ SUN_COMPILER = $(shell $(CXX) -V 2>&1 | $(EGREP) -i -c "CC: Sun")
 
 # Also see LLVM Bug 24200 (https://llvm.org/bugs/show_bug.cgi?id=24200)
 # CLANG_ASSEMBLER ?= $(shell $(CXX) -xc -c /dev/null -Wa,-v -o/dev/null 2>&1 | $(EGREP) -i -c "^clang")
-# TODO: Uncomment the line above when Clang's integrated assembler can parse inline assembly 
-CLANG_ASSEMBLER ?= 0
-GNU_ASSEMBLER ?= $(shell $(CXX) -xc -c /dev/null -Wa,-v -o/dev/null 2>&1 | $(EGREP) -i -c "^GNU assembler")
+# TODO: Uncomment the line above when Clang's integrated assembler can parse and generate code that passes the self tests.
 
 # Default prefix for make install
 ifeq ($(PREFIX),)
 PREFIX = /usr
 endif
 
-# Sadly, we can't actually use GCC_PRAGMA_AWARE with GCC because of GCC Bug 53431.
-# (https://gcc.gnu.org/bugzilla/show_bug.cgi?id=53431). Its a shame because GCC has
-# so much to offer by the way of analysis. Clang works as expected, though.
-ifneq ($(CLANG_COMPILER),0)
-CXXFLAGS += -Wall
-endif
-
 ifeq ($(IS_X86),1)
 
 GCC42_OR_LATER = $(shell $(CXX) -v 2>&1 | $(EGREP) -i -c "^gcc version (4.[2-9]|[5-9])")
 ICC111_OR_LATER = $(shell $(CXX) --version 2>&1 | $(EGREP) -c "\(ICC\) ([2-9][0-9]|1[2-9]|11\.[1-9])")
 
-ifneq ($(GNU_ASSEMBLER),0)
 # Using system provided assembler. It may be GNU AS (GAS).
 GAS210_OR_LATER ?= $(shell $(CXX) -xc -c /dev/null -Wa,-v -o/dev/null 2>&1 | $(EGREP) -c "GNU assembler version (2\.[1-9][0-9]|[3-9])")
 GAS217_OR_LATER ?= $(shell $(CXX) -xc -c /dev/null -Wa,-v -o/dev/null 2>&1 | $(EGREP) -c "GNU assembler version (2\.1[7-9]|2\.[2-9]|[3-9])")
 GAS219_OR_LATER ?= $(shell $(CXX) -xc -c /dev/null -Wa,-v -o/dev/null 2>&1 | $(EGREP) -c "GNU assembler version (2\.19|2\.[2-9]|[3-9])")
+
+# For testing and development. If CXX=clang++, then it effectively
+#   enables ASM code paths and engages the integrated assembler.
+FORCE_ASM ?= 0
+ifneq ($(FORCE_ASM),0)
+  GAS210_OR_LATER = 1
+  GAS217_OR_LATER = 1
+  GAS219_OR_LATER = 1
 endif
 
 # Enable PIC for x86_64 targets
@@ -106,7 +104,8 @@ endif # GCC 4.5
 endif # Cygwin work arounds
 
 # Build a boolean circuit that says "Darwin && (GCC 4.2 || Clang)"
-MULTIARCH_SUPPORT ?= $(shell echo $$(($(IS_DARWIN) * ($(GCC42_OR_LATER) + $(CLANG_COMPILER)))))
+# MULTIARCH_SUPPORT ?= $(shell echo $$(($(IS_DARWIN) * ($(GCC42_OR_LATER) + $(CLANG_COMPILER)))))
+MULTIARCH_SUPPORT ?= 0
 ifneq ($(MULTIARCH_SUPPORT),0)
 CXXFLAGS += -arch i386 -arch x86_64
 else
@@ -122,54 +121,41 @@ CXXFLAGS += -DCRYPTOPP_DISABLE_ASM
 endif
 endif
 
-# .intel_syntax wasn't supported until GNU assembler 2.10
-SUPPORTS_ASM ?= $(shell echo $$(($(GAS210_OR_LATER) + $(CLANG_ASSEMBLER))))
-ifeq ($(SUPPORTS_ASM),0)
+ifeq ($(GAS210_OR_LATER),0)
 CXXFLAGS += -DCRYPTOPP_DISABLE_ASM
 else
-SUPPORTS_SSE3 ?= GAS217_OR_LATER
-ifeq ($(SUPPORTS_SSE3),0)
+ifeq ($(GAS217_OR_LATER),0)
 CXXFLAGS += -DCRYPTOPP_DISABLE_SSSE3
 else
-SUPPORTS_AESNI ?= GAS219_OR_LATER
-ifeq ($(SUPPORTS_AESNI),0)
+ifeq ($(GAS219_OR_LATER),0)
 CXXFLAGS += -DCRYPTOPP_DISABLE_AESNI
-endif   # SUPPORTS_AESNI
-endif   # SUPPORTS_SSE3
+endif   # GAS219_OR_LATER
+endif   # GAS217_OR_LATER
 ifeq ($(UNAME),SunOS)
 CXXFLAGS += -Wa,--divide	# allow use of "/" operator
 endif   # SunOS
-endif   # SUPPORTS_ASM
+endif   # GAS210_OR_LATER
 
 endif	# IS_X86
 
-ifeq ($(UNAME),)	# for DJGPP, where uname doesn't exist
-CXXFLAGS += -mbnu210
-else
-CXXFLAGS += -pipe
-endif
-
 ifeq ($(IS_MINGW),1)
 LDLIBS += -lws2_32
-endif
+endif 	# IS_MINGW
 
 ifeq ($(IS_LINUX),1)
 LDFLAGS += -pthread
 ifneq ($(IS_X86_64),0)
 M32OR64 = -m64
 endif
-endif
+ifeq ($(findstring -fopenmp,$(MAKECMDGOALS)),-fopenmp)
+LDLIBS += -lgomp
+endif 	# -fopenmp
+endif 	# IS_LINUX
 
 ifneq ($(IS_DARWIN),0)
-AR = libtool
-ARFLAGS = -static -o
+AR ?= libtool
+ARFLAGS ?= -static -o
 CXX ?= c++
-IS_GCC2 = $(shell $(CXX) -v 2>&1 | $(EGREP) -c gcc-932)
-ifeq ($(IS_GCC2),1)
-CXXFLAGS += -fno-coalesce-templates -fno-coalesce-static-vtables
-LDLIBS += -lstdc++
-LDFLAGS += -flat_namespace -undefined suppress -m
-endif
 endif
 
 ifeq ($(UNAME),SunOS)
@@ -177,8 +163,22 @@ LDLIBS += -lnsl -lsocket
 M32OR64 = -m$(shell isainfo -b)
 endif
 
+# -Wall for GCC 4.4 and above. It needs -Wno-unknown-pragmas due to bug
+# https://gcc.gnu.org/bugzilla/show_bug.cgi?id=53431. We can't use -Wall
+# alone because it will light up CentOS 5 (GCC 4.1) and OpenBSD (4.2.1)
+GCC44_OR_LATER = $(shell $(CXX) -v 2>&1 | $(EGREP) -i -c "^gcc version (4.[4-9]|[5-9])")
+ifneq ($(GCC44_OR_LATER),0)
+CXXFLAGS += -Wall -Wno-unknown-pragmas
+endif
+
 ifneq ($(CLANG_COMPILER),0)
-CXXFLAGS += -Wno-tautological-compare
+CXXFLAGS += -Wall -Wno-tautological-compare
+endif
+
+ifeq ($(UNAME),)	# for DJGPP, where uname doesn't exist
+CXXFLAGS += -mbnu210
+else
+CXXFLAGS += -pipe
 endif
 
 ifneq ($(SUN_COMPILER),0)	# override flags for CC Sun C++ compiler
@@ -217,7 +217,12 @@ DLLTESTOBJS = dlltest.dllonly.o
 
 all cryptest: cryptest.exe
 static: libcryptopp.a
+	
+ifeq ($(IS_DARWIN),0)
 shared dynamic: libcryptopp.so
+else
+shared dynamic: libcryptopp.dylib
+endif
 
 asan ubsan: libcryptopp.a cryptest.exe
 
@@ -227,7 +232,7 @@ test check: cryptest.exe
 
 .PHONY: clean
 clean:
-	-$(RM) cryptest.exe libcryptopp.a libcrypto++.a libcryptopp.so libcrypto++.so $(LIBOBJS) $(TESTOBJS) cryptopp.dll libcryptopp.dll.a libcryptopp.import.a cryptest.import.exe dlltest.exe $(DLLOBJS) $(LIBIMPORTOBJS) $(TESTI MPORTOBJS) $(DLLTESTOBJS)
+	-$(RM) cryptest.exe libcryptopp.a libcrypto++.a libcryptopp.so libcrypto++.so libcryptopp.dylib $(LIBOBJS) $(TESTOBJS) cryptopp.dll libcryptopp.dll.a libcryptopp.import.a cryptest.import.exe dlltest.exe $(DLLOBJS) $(LIBIMPORTOBJS) $(TESTI MPORTOBJS) $(DLLTESTOBJS)
 	-$(RM) -r cryptest.exe.dSYM
 
 .PHONY: distclean
@@ -242,7 +247,7 @@ install:
 	$(MKDIR) -p $(PREFIX)/include/cryptopp $(PREFIX)/lib $(PREFIX)/bin
 	-$(CP) *.h $(PREFIX)/include/cryptopp
 	-$(CP) *.a $(PREFIX)/lib
-	-$(CP) *.so $(PREFIX)/lib
+	-$(CP) *.so *.dylib $(PREFIX)/lib
 	-$(CP) *.exe $(PREFIX)/bin
 
 .PHONY: install-strip
@@ -254,12 +259,14 @@ install-strip: libcryptopp.a cryptest.exe
 	-$(CP) *.exe $(PREFIX)/bin
 	-$(STRIP) -s $(PREFIX)/bin/cryptest.exe
 	-$(STRIP) -s $(PREFIX)/lib/libcryptopp.so
+	-$(STRIP) -s $(PREFIX)/lib/libcryptopp.dylib
 
 .PHONY: uninstall remove
 uninstall remove:
 	-$(RM) -rf $(PREFIX)/include/cryptopp
 	-$(RM) $(PREFIX)/lib/libcryptopp.a
 	-$(RM) $(PREFIX)/lib/libcryptopp.so
+	-$(RM) $(PREFIX)/lib/libcryptopp.dylib
 	-$(RM) $(PREFIX)/bin/cryptest.exe
 
 .PHONY: dist
@@ -276,8 +283,12 @@ libcryptopp.a: $(LIBOBJS)
 	$(RANLIB) $@
 
 libcryptopp.so: $(LIBOBJS)
-	$(CXX) -shared -o $@ $(LIBOBJS)
+	$(CXX) -shared -o $@ $(CXXFLAGS) $(LIBOBJS)
+	
+libcryptopp.dylib: $(LIBOBJS)
+	$(CXX) -shared -dynamiclib -o $@ $(CXXFLAGS) $(LIBOBJS)
 
+.PHONY: cryptest.exe
 cryptest.exe: libcryptopp.a $(TESTOBJS)
 	$(CXX) -o $@ $(CXXFLAGS) $(TESTOBJS) ./libcryptopp.a $(LDFLAGS) $(LDLIBS)
 
diff --git a/config.h b/config.h
index b153995d..7d8bda34 100644
--- a/config.h
+++ b/config.h
@@ -74,11 +74,16 @@
 // When the LLVM project fixes it, then we turn it on/off automatically.
 #define WORKAROUND_LLVM_BUG_18916
 
+// Define this if you are working around Clang's integrated assembler bug
+// and issues ".intel_syntax" (https://llvm.org/bugs/show_bug.cgi?id=24232).
+// When the LLVM project fixes it, then we turn it on/off automatically.
+#define WORKAROUND_LLVM_BUG_24232
+
 // Define this if you are working with Clang's integrated assembler. As far as we know,
-// the only way to tell is `$(CXX) -xc -c /dev/null -Wa,-v -o/dev/null 2>&1`. The
-// integrated assembler will return `clang: error: unsupported argument '-v' option`.
+//   the only way to tell is `$(CXX) -xc -c /dev/null -Wa,-v -o/dev/null 2>&1`. The
+//   integrated assembler will return `clang: error: unsupported argument '-v' option`.
 #if defined(__clang__)
-#define CRYPTOPP_CLANG_INTEGRATED_ASSEMBLER
+# define CRYPTOPP_CLANG_INTEGRATED_ASSEMBLER
 #endif
 
 #ifdef CRYPTOPP_DOXYGEN_PROCESSING
diff --git a/gcm.cpp b/gcm.cpp
index cef52bc6..34addadc 100644
--- a/gcm.cpp
+++ b/gcm.cpp
@@ -671,12 +671,11 @@ size_t GCM_Base::AuthenticateBlocks(const byte *data, size_t len)
 		AS2(	movdqa	xmm1, xmm2						)
 		AS2(	pslldq	xmm2, 1							)
 		AS2(	pxor	xmm5, xmm2						)
-
 		AS2(	psrldq	xmm0, 15						)
-#if defined(CRYPTOPP_USING_CLANG_INTEGRATED_ASSEMBLER)
-		AS2(	movq	WORD_REG(di), xmm0					)
+#if defined(CRYPTOPP_CLANG_INTEGRATED_ASSEMBLER)
+		AS2(	movd	WORD_REG32(di), xmm0			)
 #else
-		AS2(	movd	WORD_REG(di), xmm0					)
+		AS2(	movd	WORD_REG(di), xmm0				)
 #endif
 		AS2(	movzx	eax, WORD PTR [RED_TABLE + WORD_REG(di)*2]	)
 		AS2(	shl		eax, 8							)
@@ -687,29 +686,29 @@ size_t GCM_Base::AuthenticateBlocks(const byte *data, size_t len)
 
 		AS2(	psrldq	xmm1, 15						)
 
-#if defined(CRYPTOPP_USING_CLANG_INTEGRATED_ASSEMBLER)
-		AS2(	movq	WORD_REG(di), xmm1					)
+#if defined(CRYPTOPP_CLANG_INTEGRATED_ASSEMBLER)
+		AS2(	movd	WORD_REG32(di), xmm1			)
 #else
-		AS2(	movd	WORD_REG(di), xmm1					)
+		AS2(	movd	WORD_REG(di), xmm1				)
 #endif
 		AS2(	xor		ax, WORD PTR [RED_TABLE + WORD_REG(di)*2]	)
 		AS2(	shl		eax, 8							)
 
 		AS2(	psrldq	xmm0, 15						)
-#if defined(CRYPTOPP_USING_CLANG_INTEGRATED_ASSEMBLER)
-		AS2(	movq	WORD_REG(di), xmm0					)
+#if defined(CRYPTOPP_CLANG_INTEGRATED_ASSEMBLER)
+		AS2(	movd	WORD_REG32(di), xmm0			)
 #else
-		AS2(	movd	WORD_REG(di), xmm0					)
+		AS2(	movd	WORD_REG(di), xmm0				)
 #endif
 		AS2(	xor		ax, WORD PTR [RED_TABLE + WORD_REG(di)*2]	)
 
 		AS2(	movd	xmm0, eax						)
 		AS2(	pxor	xmm0, xmm4						)
 
-		AS2(	add		WORD_REG(cx), 16					)
-		AS2(	sub		WORD_REG(dx), 1						)
+		AS2(	add		WORD_REG(cx), 16				)
+		AS2(	sub		WORD_REG(dx), 1					)
 		ASJ(	jnz,	0, b							)
-		AS2(	movdqa	[WORD_REG(si)], xmm0				)
+		AS2(	movdqa	[WORD_REG(si)], xmm0			)
 
 		AS_POP_IF86(	bp)
 		AS_POP_IF86(	bx)