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| author | Jason Merrill <jason@redhat.com> | 2010-05-05 12:32:20 -0400 |
|---|---|---|
| committer | Jason Merrill <jason@gcc.gnu.org> | 2010-05-05 12:32:20 -0400 |
| commit | 6d729f282c059987f966fc3d9c98eb74e2d92839 (patch) | |
| tree | 76394a4dd6bd685ffee7f55fc84a357aecb19236 /gcc/cp/cp-gimplify.c | |
| parent | a2c9b836ba7e2781effde72da473534cb32743ee (diff) | |
| download | gcc-6d729f282c059987f966fc3d9c98eb74e2d92839.zip gcc-6d729f282c059987f966fc3d9c98eb74e2d92839.tar.gz gcc-6d729f282c059987f966fc3d9c98eb74e2d92839.tar.bz2 | |
re PR c++/43787 (memory copy of empty class (sizeof is one))
PR c++/43787
gcc:
* gimplify.c (gimplify_expr): Keep working if gimplify_modify_expr
returns GS_OK.
(gimplify_modify_expr_rhs): Return GS_OK if anything changed.
gcc/cp:
* cp-gimplify.c (cp_gimplify_expr): Remove copies of empty classes.
* call.c (build_over_call): Don't try to avoid INIT_EXPR copies here.
From-SVN: r159072
Diffstat (limited to 'gcc/cp/cp-gimplify.c')
| -rw-r--r-- | gcc/cp/cp-gimplify.c | 20 |
1 files changed, 20 insertions, 0 deletions
diff --git a/gcc/cp/cp-gimplify.c b/gcc/cp/cp-gimplify.c index 533d2d1..d6ae28f 100644 --- a/gcc/cp/cp-gimplify.c +++ b/gcc/cp/cp-gimplify.c @@ -569,6 +569,26 @@ cp_gimplify_expr (tree *expr_p, gimple_seq *pre_p, gimple_seq *post_p) && !useless_type_conversion_p (TREE_TYPE (op1), TREE_TYPE (op0))) TREE_OPERAND (*expr_p, 1) = build1 (VIEW_CONVERT_EXPR, TREE_TYPE (op0), op1); + + else if ((rhs_predicate_for (op0)) (op1) + && !(TREE_CODE (op1) == CALL_EXPR + && CALL_EXPR_RETURN_SLOT_OPT (op1)) + && is_really_empty_class (TREE_TYPE (op0))) + { + /* Remove any copies of empty classes. We check that the RHS + has a simple form so that TARGET_EXPRs and CONSTRUCTORs get + reduced properly, and we leave the return slot optimization + alone because it isn't a copy. + + Also drop volatile variables on the RHS to avoid infinite + recursion from gimplify_expr trying to load the value. */ + if (!TREE_SIDE_EFFECTS (op1) + || (DECL_P (op1) && TREE_THIS_VOLATILE (op1))) + *expr_p = op0; + else + *expr_p = build2 (COMPOUND_EXPR, TREE_TYPE (*expr_p), + op0, op1); + } } ret = GS_OK; break; |