Fix C++ template instantiation back end core dump.

	* varasm.c (mark_constants): Don't look inside CONST_DOUBLEs.

From-SVN: r14999

gcc/ChangeLog

+Fri Aug 29 11:42:04 1997  Jim Wilson  <wilson@cygnus.com>
+
+	* varasm.c (mark_constants): Don't look inside CONST_DOUBLEs.
+
 Fri Aug 29 09:33:20 1997  Philipp Thomas  (kthomas@lxi165.gwdg.de)
 
 	* dwarfout2.c (build_abbrev_table): Use xrealloc, not xmalloc

gcc/varasm.c

@@ -3798,6 +3798,13 @@ mark_constants (x)
 	find_pool_constant (x)->mark = 1;
       return;
     }
+  /* Never search inside a CONST_DOUBLE, because CONST_DOUBLE_MEM may be
+     a MEM, but does not constitute a use of that MEM.  This is particularly
+     important inside a nested function, because CONST_DOUBLE_MEM may be
+     a reference to a MEM in the parent's constant pool.  See the comment
+     in force_const_mem.  */
+  else if (GET_CODE (x) == CONST_DOUBLE)
+    return;
 
   /* Insns may appear inside a SEQUENCE.  Only check the patterns of
      insns, not any notes that may be attached.  We don't want to mark