* acconfig.h: added BROKEN_GCSE.

	* configure.in: check for a gcc GCSE optimisation bug.

diff --git a/acconfig.h b/acconfig.h
index b7b42bc..cf5e0ff 100644 (file)
--- a/acconfig.h
+++ b/acconfig.h
@@ -154,3 +154,6 @@
 
 /* Define if the compiler supports long longs.  */
 #undef HAVE_LONG_LONGS
+
+/* Define if GCC has GCSE optimisation bug.  */
+#undef BROKEN_GCSE

diff --git a/configure.in b/configure.in
index 09e897d..3c4126e 100644 (file)
--- a/configure.in
+++ b/configure.in
@@ -129,6 +129,33 @@ if test "$scm_cv_long_longs" = yes; then
   AC_DEFINE(HAVE_LONG_LONGS)
 fi
 
+dnl check for an optimisation problem which is present in some versions
+dnl of gcc, including 2.95.2.
+AC_MSG_CHECKING(for broken GCSE optimisation)
+AC_CACHE_VAL(guile_cv_broken_gcse,
+   AC_TRY_RUN([
+       int main ()
+       {
+         long winds = 0;
+
+         while (winds != 0)
+           {
+             if (*(char *) 0)
+               break;
+           }
+
+         if (winds == 0 || *(char *) 0)
+           exit (0);
+
+         return 0;
+       }],
+        guile_cv_broken_gcse=no, guile_cv_broken_gcse=yes,
+        guile_cv_broken_gcse=yes))
+AC_MSG_RESULT($guile_cv_broken_gcse)
+if test $guile_cv_broken_gcse = yes; then
+   AC_DEFINE(BROKEN_GCSE)
+fi
+
 AC_HEADER_STDC
 AC_HEADER_DIRENT
 AC_HEADER_TIME