diff options
Diffstat (limited to 'gcc/tree.c')
-rw-r--r-- | gcc/tree.c | 67 |
1 files changed, 67 insertions, 0 deletions
diff --git a/gcc/tree.c b/gcc/tree.c index 8cf75f22220..efa49e99d65 100644 --- a/gcc/tree.c +++ b/gcc/tree.c @@ -11376,6 +11376,73 @@ initializer_each_zero_or_onep (const_tree expr) } } +/* Given an initializer INIT for a TYPE, return true if INIT is zero + so that it can be replaced by value initialization. This function + distinguishes betwen empty strings as initializers for arrays and + for pointers (which make it return false). */ + +bool +type_initializer_zero_p (tree type, tree init) +{ + if (type == error_mark_node || init == error_mark_node) + return false; + + STRIP_NOPS (init); + + if (POINTER_TYPE_P (type)) + return TREE_CODE (init) != STRING_CST && initializer_zerop (init); + + if (TREE_CODE (init) != CONSTRUCTOR) + return initializer_zerop (init); + + if (TREE_CODE (type) == ARRAY_TYPE) + { + tree elt_type = TREE_TYPE (type); + elt_type = TYPE_MAIN_VARIANT (elt_type); + if (elt_type == char_type_node) + return initializer_zerop (init); + + tree elt_init; + unsigned HOST_WIDE_INT i; + FOR_EACH_CONSTRUCTOR_VALUE (CONSTRUCTOR_ELTS (init), i, elt_init) + if (!type_initializer_zero_p (elt_type, elt_init)) + return false; + return true; + } + + if (TREE_CODE (type) != RECORD_TYPE) + return initializer_zerop (init); + + tree fld = TYPE_FIELDS (type); + + tree fld_init; + unsigned HOST_WIDE_INT i; + FOR_EACH_CONSTRUCTOR_VALUE (CONSTRUCTOR_ELTS (init), i, fld_init) + { + /* Advance to the next member, skipping over everything that + canot be initialized (including unnamed bit-fields). */ + while (TREE_CODE (fld) != FIELD_DECL + || DECL_ARTIFICIAL (fld) + || (DECL_BIT_FIELD (fld) && !DECL_NAME (fld))) + { + fld = DECL_CHAIN (fld); + if (!fld) + return true; + continue; + } + + tree fldtype = TREE_TYPE (fld); + if (!type_initializer_zero_p (fldtype, fld_init)) + return false; + + fld = DECL_CHAIN (fld); + if (!fld) + break; + } + + return true; +} + /* Check if vector VEC consists of all the equal elements and that the number of elements corresponds to the type of VEC. The function returns first element of the vector |