diff --git a/GNUmakefile b/GNUmakefile
index db1713f6..dc987bce 100755
--- a/GNUmakefile
+++ b/GNUmakefile
@@ -21,6 +21,8 @@ IS_X64 := $(shell uname -m | $(EGREP) -i -c "(_64|d64)")
 IS_PPC := $(shell uname -m | $(EGREP) -i -c "ppc|power")
 IS_ARM32 := $(shell uname -m | $(EGREP) -i -c "arm")
 IS_ARM64 := $(shell uname -m | $(EGREP) -i -c "aarch64")
+IS_SPARC := $(shell uname -m | $(EGREP) -i -c "sparc")
+IS_SPARC64 := $(shell uname -m | $(EGREP) -i -c "sparc64")
 
 IS_SUN := $(shell uname | $(EGREP) -i -c "SunOS")
 IS_LINUX := $(shell $(CXX) -dumpmachine 2>&1 | $(EGREP) -i -c "Linux")
@@ -346,6 +348,10 @@ CXXFLAGS += -KPIC
 endif
 # Add to all Solaris
 CXXFLAGS += -template=no%extdef
+# http://github.com/weidai11/cryptopp/issues/403
+ifneq ($(IS_SPARC)$(IS_SPARC64),00)
+CXXFLAGS += -xmemalign=4i
+endif
 SUN_CC10_BUGGY := $(shell $(CXX) -V 2>&1 | $(EGREP) -c "CC: Sun .* 5\.10 .* (2009|2010/0[1-4])")
 ifneq ($(SUN_CC10_BUGGY),0)
 # -DCRYPTOPP_INCLUDE_VECTOR_CC is needed for Sun Studio 12u1 Sun C++ 5.10 SunOS_i386 128229-02 2009/09/21 and was fixed in May 2010