On Tue, Jan 13, 2026 at 6:47 AM Jeffrey Law
<[email protected]> wrote:
>
>
>
> On 1/13/2026 4:31 AM, Richard Biener wrote:
> > On Tue, Jan 13, 2026 at 12:16 PM Daniel Barboza
> > <[email protected]> wrote:
> >> During ML discussions of a match.pd pattern that was introducing a new
> >> instance of 'warn_strict_overflow', Richard mentioned that this use
> >> should be discouraged [1]. After pointing out that this usage was
> >> documented in tree.h he then explained that we should remove the note
> >> from the header [2]. Here's the reasoning:
> >>
> >> "Ah, we should remove that note.  -Wstrict-overflow proved useless IMO,
> >> it's way too noisy as it diagnoses when the compiler relies on overflow
> >> not happening, not diagnosing when it possibly happens.  That's not a
> >> very useful diagnostic to have - it does not point to a possible problem
> >> in the code (we could as well diagnose _all_ signed arithmetic
> >> operations for the same argument that we might eventually rely on
> >> overflow not happening)."
> >>
> >> Aside from removing the tree.h node we're also removing the 2 references
> >> in match.pd. match.pd patterns tend to be copied around to serve as a
> >> base for new patterns (like I did in [3] adding a
> >> 'fold_overflow_warning'), and if we want to discourage the use avoiding
> >> its spread is a good start.
> >>
> >> Note that there are a lot of references left, most of them in
> >> gcc/fold-const.cc. Some references are using in nested helpers inside
> >> the file, entangled with code that does other things. Removing all
> >> references from the project is out of scope for this quick patch.
> >>
> >> [1] https://gcc.gnu.org/pipermail/gcc-patches/2026-January/705320.html
> >> [2] https://gcc.gnu.org/pipermail/gcc-patches/2026-January/705482.html
> >> [3] https://gcc.gnu.org/pipermail/gcc-patches/2026-January/704992.html
> > OK.
> I think it's time to get Daniel write-after-approval permissions so he
> can commit stuff himself....

Agreed.

>
> jeff

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