xdiff: load full words in the inner loop of xdl_hash_record

diff --git a/Makefile b/Makefile
index be1957a5e986d2e0581123dfe4e0eeb6702c13dc..13ed1b1d29299cf69bbd8cec69f40d313a86a9f5 100644 (file)
--- a/Makefile
+++ b/Makefile
@@ -288,6 +288,11 @@ all::
 # dependency rules.
 #
 # Define NATIVE_CRLF if your platform uses CRLF for line endings.
+#
+# Define XDL_FAST_HASH to use an alternative line-hashing method in
+# the diff algorithm.  It gives a nice speedup if your processor has
+# fast unaligned word loads.  Does NOT work on big-endian systems!
+# Enabled by default on x86_64.
 
 GIT-VERSION-FILE: FORCE
        @$(SHELL_PATH) ./GIT-VERSION-GEN
@@ -864,6 +869,9 @@ EXTLIBS =
 # because maintaining the nesting to match is a pain.  If
 # we had "elif" things would have been much nicer...
 
+ifeq ($(uname_M),x86_64)
+       XDL_FAST_HASH = YesPlease
+endif
 ifeq ($(uname_S),OSF1)
        # Need this for u_short definitions et al
        BASIC_CFLAGS += -D_OSF_SOURCE
@@ -1737,6 +1745,10 @@ ifndef NO_MSGFMT_EXTENDED_OPTIONS
        MSGFMT += --check --statistics
 endif
 
+ifneq (,$(XDL_FAST_HASH))
+       BASIC_CFLAGS += -DXDL_FAST_HASH
+endif
+
 ifeq ($(TCLTK_PATH),)
 NO_TCLTK=NoThanks
 endif