On Tue, Dec 19, 2017 at 3:49 PM, Jakub Jelinek <ja...@redhat.com> wrote:
> On Tue, Dec 19, 2017 at 03:13:13PM -0500, Jason Merrill wrote:
>> On 12/17/2017 09:07 PM, David Malcolm wrote:
>> > On Mon, 2017-12-11 at 18:37 -0500, Jason Merrill wrote:
>> > > On 11/10/2017 04:45 PM, David Malcolm wrote:
>> > > > gcc/c-family/ChangeLog:
>> > > > * c-warn.c (sizeof_pointer_memaccess_warning): Strip any
>> > > > location
>> > > > wrappers from src and dest.
>> > >
>> > > Here the existing calls to tree_strip_nop_conversions ought to
>> > > handle
>> > > the wrappers.
>> >
>> > They don't; when EXP is a VIEW_CONVERT_EXPR wrapper around a VAR_DECL...
>> >
>> > 11887 static inline bool
>> > 11888 tree_nop_conversion (const_tree exp)
>> > 11889 {
>> > 11890 tree outer_type, inner_type;
>> > 11891
>> > 11892 if (!CONVERT_EXPR_P (exp)
>> > 11893 && TREE_CODE (exp) != NON_LVALUE_EXPR)
>> > 11894 return false;
>> >
>> > ...tree_nop_conversion bails out at this "return false;", and hence
>> > tree_strip_nop_conversions simply returns the wrapper that was passed
>> > in.
>>
>> Right. So let's change tree_nop_conversion to return true.
>
> I'd fear that would break too much stuff, VIEW_CONVERT_EXPR is not
> a normal conversion, but reinterpretation of the bits.
>
> Or do you mean it should strip just the special VIEW_CONVERT_EXPR
> that has type identical to the operand's type?
That; interpreting something as the same type seems like a nop.
Jason
