From 53ead5787921be799593232cfc9931f916b79002 Mon Sep 17 00:00:00 2001 From: Jakub Jelinek Date: Thu, 13 Jan 2022 15:59:47 +0100 Subject: [PATCH] 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 PR tree-optimization/103989 * tree-inline.c (setup_one_parameter): Don't copy parms with empty type. --- gcc/tree-inline.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/gcc/tree-inline.c b/gcc/tree-inline.c index d7fc33e..8ea8de7 100644 --- a/gcc/tree-inline.c +++ b/gcc/tree-inline.c @@ -3608,7 +3608,7 @@ setup_one_parameter (copy_body_data *id, tree p, tree value, tree fn, init_stmt = gimple_build_assign (def, rhs); } } - else + else if (!is_empty_type (TREE_TYPE (var))) init_stmt = gimple_build_assign (var, rhs); if (bb && init_stmt) -- 2.7.4