https://gcc.gnu.org/bugzilla/show_bug.cgi?id=89765
--- Comment #5 from Richard Biener <rguenth at gcc dot gnu.org> ---
I think the issue is that we gimplify
VIEW_CONVERT_EXPR<__int128 unsigned>(<<< Unknown tree: compound_literal_expr
V D.2833 = y; >>>)
via
12399 case VIEW_CONVERT_EXPR:
12400 if (is_gimple_reg_type (TREE_TYPE (*expr_p))
12401 && is_gimple_reg_type (TREE_TYPE (TREE_OPERAND (*expr_p,
0))))
12402 {
12403 ret = gimplify_expr (&TREE_OPERAND (*expr_p, 0), pre_p,
12404 post_p, is_gimple_val, fb_rvalue);
(gdb) l
12405 recalculate_side_effects (*expr_p);
12406 break;
when in gimplify_expr with fallback == fb_lvalue and gimple_test_f ==
is_gimple_lvalue. If we fix that with
Index: gcc/gimplify.c
===================================================================
--- gcc/gimplify.c (revision 270437)
+++ gcc/gimplify.c (working copy)
@@ -12397,7 +12397,8 @@ gimplify_expr (tree *expr_p, gimple_seq
break;
case VIEW_CONVERT_EXPR:
- if (is_gimple_reg_type (TREE_TYPE (*expr_p))
+ if ((fallback & fb_rvalue)
+ && is_gimple_reg_type (TREE_TYPE (*expr_p))
&& is_gimple_reg_type (TREE_TYPE (TREE_OPERAND (*expr_p, 0))))
{
ret = gimplify_expr (&TREE_OPERAND (*expr_p, 0), pre_p,
then we gimplify to the correct
VIEW_CONVERT_EXPR<__int128 unsigned>(D.2833) = x;
and yes, we could move the VIEW_CONVERT_EXPR to the RHS as a trick to make
D.2833 SSA rewritable in update-address-taken.
Have to think whether requiring fallback & fb_rvalue is to be used or
if fallback != fb_lvalue is better. I guess the latter.
