diff options
Diffstat (limited to 'gcc/gimplify.c')
| -rw-r--r-- | gcc/gimplify.c | 40 |
1 files changed, 40 insertions, 0 deletions
diff --git a/gcc/gimplify.c b/gcc/gimplify.c index df93bc5dde8..81512728dc5 100644 --- a/gcc/gimplify.c +++ b/gcc/gimplify.c @@ -3015,6 +3015,46 @@ gimplify_modify_expr_rhs (tree *expr_p, tree *from_p, tree *to_p, tree *pre_p, ret = GS_UNHANDLED; break; + case CALL_EXPR: + /* For calls that return in memory, give *to_p as the CALL_EXPR's + return slot so that we don't generate a temporary. */ + if (!CALL_EXPR_RETURN_SLOT_OPT (*from_p) + && aggregate_value_p (*from_p, *from_p)) + { + bool use_target; + + if (TREE_CODE (*to_p) == RESULT_DECL + && needs_to_live_in_memory (*to_p)) + /* It's always OK to use the return slot directly. */ + use_target = true; + else if (!is_gimple_non_addressable (*to_p)) + /* Don't use the original target if it's already addressable; + if its address escapes, and the called function uses the + NRV optimization, a conforming program could see *to_p + change before the called function returns; see c++/19317. + When optimizing, the return_slot pass marks more functions + as safe after we have escape info. */ + use_target = false; + else if (DECL_GIMPLE_FORMAL_TEMP_P (*to_p)) + /* Don't use the original target if it's a formal temp; we + don't want to take their addresses. */ + use_target = false; + else if (is_gimple_reg_type (TREE_TYPE (*to_p))) + /* Also don't force regs into memory. */ + use_target = false; + else + use_target = true; + + if (use_target) + { + CALL_EXPR_RETURN_SLOT_OPT (*from_p) = 1; + lang_hooks.mark_addressable (*to_p); + } + } + + ret = GS_UNHANDLED; + break; + default: ret = GS_UNHANDLED; break; |
