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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 gcc/ChangeLog: * match.pd: remove 'fold_overflow_warning' references. * tree.h (TYPE_OVERFLOW_UNDEFINED): remove note telling that we must use warn_strict_overflow for every optimization based on TYPE_OVERFLOW_UNDEFINED. gcc/testsuite/ChangeLog: * gcc.dg/Wstrict-overflow-1.c: Removed because we no longer issue a 'fold_overflow_warning' with the `(le (minus (@0 INTEGER_CST@1)) INTEGER_CST@2)` pattern. Signed-off-by: Daniel Barboza <daniel.barboza@oss.qualcomm.com>
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