Hi, Richard,
For the following, I need more clarification:
+/* Expand the IFN_DEFERRED_INIT function according to its second
argument. */
+static void
+expand_DEFERRED_INIT (internal_fn, gcall *stmt)
+{
+ tree var = gimple_call_lhs (stmt);
+ tree init = NULL_TREE;
+ enum auto_init_type init_type
+ = (enum auto_init_type) TREE_INT_CST_LOW (gimple_call_arg (stmt, 1));
+
+ switch (init_type)
+ {
+ default:
+ gcc_unreachable ();
+ case AUTO_INIT_PATTERN:
+ init = build_pattern_cst_for_auto_init (TREE_TYPE (var));
+ expand_assignment (var, init, false);
+ break;
+ case AUTO_INIT_ZERO:
+ init = build_zero_cst (TREE_TYPE (var));
+ expand_assignment (var, init, false);
+ break;
+ }
I think actually building build_pattern_cst_for_auto_init can generate
massive garbage and for big auto vars code size is also a concern and
ideally on x86 you'd produce rep movq. So I don't think going
via expand_assignment is good. Instead you possibly want to lower
.DEFERRED_INIT to MEMs following expand_builtin_memset and
eventually enhance that to allow storing pieces larger than a byte.
I will lower .DEFFERED_INIT to MEMS following expand_builtin_memset for
“AUTO_INIT_PATTERN”.
My question is:
Do I need to do the same for “AUTO_INIT_ZERO”?
Thanks.
Qing
