[Bug middle-end/44790] [4.6 Regression] Bootstrap fails after MEM-REF merge

["sje at cup dot hp dot com" <gcc-bugzilla@gcc.gnu.org>]

------- Comment #3 from sje at cup dot hp dot com  2010-07-06 16:44 -------
The neccessary UNSPEC seems to be there if you trace the instructions back
far enough.  I tried it on my test case and it worked.  I am now testing the
patch on ToT to see if I can bootstrap.  I also have to turn off partial
inlining to get bootstrap to work on ia64-hp-hpux11.23.  I tweaked the patch
for ToT there are a bunch of changes to expr.c including setting base so the
patch I am currently testing with r161861 looks like this:

Index: expr.c
===================================================================
--- expr.c      (revision 161861)
+++ expr.c      (working copy)
@@ -8777,13 +8777,11 @@ expand_expr_real_1 (tree exp, rtx target
          base = build2 (BIT_AND_EXPR, TREE_TYPE (base),
                         gimple_assign_rhs1 (def_stmt),
                         gimple_assign_rhs2 (def_stmt));
-       op0 = expand_expr (base, NULL_RTX, address_mode, EXPAND_NORMAL);
        if (!integer_zerop (TREE_OPERAND (exp, 1)))
-         {
-           rtx off;
-           off = immed_double_int_const (mem_ref_offset (exp), address_mode);
-           op0 = simplify_gen_binary (PLUS, address_mode, op0, off);
-         }
+         base = build2 (POINTER_PLUS_EXPR, TREE_TYPE (base),
+                        base, double_int_to_tree (sizetype,
+                                                  mem_ref_offset (exp)));
+       op0 = expand_expr (base, NULL_RTX, address_mode, EXPAND_SUM);
        op0 = memory_address_addr_space (mode, op0, as);
        temp = gen_rtx_MEM (mode, op0);
        set_mem_attributes (temp, exp, 0);


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http://gcc.gnu.org/bugzilla/show_bug.cgi?id=44790