inliner: Don't emit copy stmts for empty type parameters [PR103989]
The following patch avoids emitting a parameter copy statement when inlining
if the parameter has empty type. E.g. the gimplifier does something similar
(except that it needs to evaluate side-effects if any, which isn't the case
here):
/* For empty types only gimplify the left hand side and right hand
side as statements and throw away the assignment. Do this after
gimplify_modify_expr_rhs so we handle TARGET_EXPRs of addressable
types properly. */
if (is_empty_type (TREE_TYPE (*from_p))
&& !want_value
/* Don't do this for calls that return addressable types, expand_call
relies on those having a lhs. */
&& !(TREE_ADDRESSABLE (TREE_TYPE (*from_p))
&& TREE_CODE (*from_p) == CALL_EXPR))
{
gimplify_stmt (from_p, pre_p);
gimplify_stmt (to_p, pre_p);
*expr_p = NULL_TREE;
return GS_ALL_DONE;
}
Unfortunately, this patch doesn't cure the uninit warnings in that PR,
which is caused by ipa inlining happening even at -Og when the post-IPA
-Og passes don't expect the need to clean up after ipa inlining,
but I think is desirable anyway.
2022-01-13 Jakub Jelinek <jakub@redhat.com>
PR tree-optimization/103989
* tree-inline.c (setup_one_parameter): Don't copy parms with
empty type.