diff options
Diffstat (limited to 'gcc/varasm.c')
| -rw-r--r-- | gcc/varasm.c | 42 |
1 files changed, 32 insertions, 10 deletions
diff --git a/gcc/varasm.c b/gcc/varasm.c index ba25f65..693196e 100644 --- a/gcc/varasm.c +++ b/gcc/varasm.c @@ -3463,7 +3463,14 @@ initializer_constant_valid_p (tree value, tree endtype) case ADDR_EXPR: case FDESC_EXPR: - return staticp (TREE_OPERAND (value, 0)) ? TREE_OPERAND (value, 0) : 0; + value = staticp (TREE_OPERAND (value, 0)); + /* "&(*a).f" is like unto pointer arithmetic. If "a" turns out to + be a constant, this is old-skool offsetof-like nonsense. */ + if (value + && TREE_CODE (value) == INDIRECT_REF + && TREE_CONSTANT (TREE_OPERAND (value, 0))) + return null_pointer_node; + return value; case VIEW_CONVERT_EXPR: case NON_LVALUE_EXPR: @@ -3565,16 +3572,17 @@ initializer_constant_valid_p (tree value, tree endtype) /* Since GCC guarantees that string constants are unique in the generated code, a subtraction between two copies of the same constant string is absolute. */ - if (valid0 && TREE_CODE (valid0) == STRING_CST && - valid1 && TREE_CODE (valid1) == STRING_CST && - TREE_STRING_POINTER (valid0) == TREE_STRING_POINTER (valid1)) + if (valid0 && TREE_CODE (valid0) == STRING_CST + && valid1 && TREE_CODE (valid1) == STRING_CST + && operand_equal_p (valid0, valid1, 1)) return null_pointer_node; } - /* Support differences between labels. */ + /* Support narrowing differences. */ if (INTEGRAL_TYPE_P (endtype)) { tree op0, op1; + op0 = TREE_OPERAND (value, 0); op1 = TREE_OPERAND (value, 1); @@ -3609,11 +3617,25 @@ initializer_constant_valid_p (tree value, tree endtype) op1 = inner; } - if (TREE_CODE (op0) == ADDR_EXPR - && TREE_CODE (TREE_OPERAND (op0, 0)) == LABEL_DECL - && TREE_CODE (op1) == ADDR_EXPR - && TREE_CODE (TREE_OPERAND (op1, 0)) == LABEL_DECL) - return null_pointer_node; + op0 = initializer_constant_valid_p (op0, endtype); + op1 = initializer_constant_valid_p (op1, endtype); + + /* Both initializers must be known. */ + if (op0 && op1) + { + if (op0 == op1) + return null_pointer_node; + + /* Support differences between labels. */ + if (TREE_CODE (op0) == LABEL_DECL + && TREE_CODE (op1) == LABEL_DECL) + return null_pointer_node; + + if (TREE_CODE (op0) == STRING_CST + && TREE_CODE (op1) == STRING_CST + && operand_equal_p (op0, op1, 1)) + return null_pointer_node; + } } break; |