Turn off strict aliasing when using AIX xlc compiler.

autoconf run.

configure

@@ -2715,8 +2715,7 @@ fi
 # The Intel compiler on Linux supports most gcc options, but not
 # all of them, so only add these options if we are really using
-# gcc.  Intel compiler has a bug in checking for division by NAN
-# (NaN == 0), -mp1 fixes it, so someday we might way to add it.
+# gcc.
 if test "$GCC" = yes; then
@@ -2934,6 +2933,61 @@ echo "${ECHO_T}no" >&6
 fi
 rm -f conftest.err conftest.$ac_objext conftest.$ac_ext
+elif test ${CC} = "xlc"; then
+  # AIX xlc has to have strict aliasing turned off too
+  echo "$as_me:$LINENO: checking if $CC supports -qnoansialias" >&5
+echo $ECHO_N "checking if $CC supports -qnoansialias... $ECHO_C" >&6
+pgac_save_CFLAGS=$CFLAGS
+CFLAGS="$pgac_save_CFLAGS -qnoansialias"
+cat >conftest.$ac_ext <<_ACEOF
+/* confdefs.h.  */
+_ACEOF
+cat confdefs.h >>conftest.$ac_ext
+cat >>conftest.$ac_ext <<_ACEOF
+/* end confdefs.h.  */
+
+int
+main ()
+{
+
+  ;
+  return 0;
+}
+_ACEOF
+rm -f conftest.$ac_objext
+if { (eval echo "$as_me:$LINENO: \"$ac_compile\"") >&5
+  (eval $ac_compile) 2>conftest.er1
+  ac_status=$?
+  grep -v '^ *+' conftest.er1 >conftest.err
+  rm -f conftest.er1
+  cat conftest.err >&5
+  echo "$as_me:$LINENO: \$? = $ac_status" >&5
+  (exit $ac_status); } &&
+	 { ac_try='test -z "$ac_c_werror_flag"
+			 || test ! -s conftest.err'
+  { (eval echo "$as_me:$LINENO: \"$ac_try\"") >&5
+  (eval $ac_try) 2>&5
+  ac_status=$?
+  echo "$as_me:$LINENO: \$? = $ac_status" >&5
+  (exit $ac_status); }; } &&
+	 { ac_try='test -s conftest.$ac_objext'
+  { (eval echo "$as_me:$LINENO: \"$ac_try\"") >&5
+  (eval $ac_try) 2>&5
+  ac_status=$?
+  echo "$as_me:$LINENO: \$? = $ac_status" >&5
+  (exit $ac_status); }; }; then
+  echo "$as_me:$LINENO: result: yes" >&5
+echo "${ECHO_T}yes" >&6
+else
+  echo "$as_me: failed program was:" >&5
+sed 's/^/| /' conftest.$ac_ext >&5
+
+CFLAGS="$pgac_save_CFLAGS"
+                    echo "$as_me:$LINENO: result: no" >&5
+echo "${ECHO_T}no" >&6
+fi
+rm -f conftest.err conftest.$ac_objext conftest.$ac_ext
+
 fi
 # supply -g if --enable-debug

configure.in

 dnl Process this file with autoconf to produce a configure script.
-dnl $PostgreSQL: pgsql/configure.in,v 1.460 2006/04/22 00:29:41 momjian Exp $
+dnl $PostgreSQL: pgsql/configure.in,v 1.461 2006/04/27 14:27:04 momjian Exp $
 dnl
 dnl Developers, please strive to achieve this order:
 dnl
@@ -267,6 +267,9 @@ choke me
 
   # Disable strict-aliasing rules; needed for gcc 3.3+
   PGAC_PROG_CC_CFLAGS_OPT([-fno-strict-aliasing])
+elif test ${CC} = "xlc"; then
+  # AIX xlc has to have strict aliasing turned off too
+  PGAC_PROG_CC_CFLAGS_OPT([-qnoansialias])
 fi
 
 # supply -g if --enable-debug