Ping.
On Thu, Aug 29, 2024 at 12:23:35PM -0400, Marek Polacek wrote:
> Bootstrapped/regtested on x86_64-pc-linux-gnu, ok for trunk/14?
>
> -- >8 --
> Pre r14-4793, we'd call warn_tautological_cmp -> operand_equal_p
> with operands wrapped in NON_DEPENDENT_EXPR, which works, since
> o_e_p bails for codes it doesn't know. But now we pass operands
> not encapsulated in NON_DEPENDENT_EXPR, and crash, because the
> template tree for &a[x] has null DECL_FIELD_OFFSET.
>
> I don't think I meant this warning to be called in a template,
> so let's avoid the problem this easy way.
>
> PR c++/116534
>
> gcc/cp/ChangeLog:
>
> * call.cc (build_new_op) <case NE_EXPR>: Don't call
> warn_tautological_cmp in a template.
>
> gcc/testsuite/ChangeLog:
>
> * g++.dg/warn/Wtautological-compare4.C: New test.
> ---
> gcc/cp/call.cc | 4 +++-
> .../g++.dg/warn/Wtautological-compare4.C | 21 +++++++++++++++++++
> 2 files changed, 24 insertions(+), 1 deletion(-)
> create mode 100644 gcc/testsuite/g++.dg/warn/Wtautological-compare4.C
>
> diff --git a/gcc/cp/call.cc b/gcc/cp/call.cc
> index fa7f05d76f6..d0d0c4b4d3c 100644
> --- a/gcc/cp/call.cc
> +++ b/gcc/cp/call.cc
> @@ -7526,7 +7526,9 @@ build_new_op (const op_location_t &loc, enum tree_code
> code, int flags,
> && ((code_orig_arg1 == BOOLEAN_TYPE)
> ^ (code_orig_arg2 == BOOLEAN_TYPE)))
> maybe_warn_bool_compare (loc, code, arg1, arg2);
> - if (complain & tf_warning && warn_tautological_compare)
> + if ((complain & tf_warning)
> + && warn_tautological_compare
> + && !processing_template_decl)
> warn_tautological_cmp (loc, code, arg1, arg2);
> /* Fall through. */
> case SPACESHIP_EXPR:
> diff --git a/gcc/testsuite/g++.dg/warn/Wtautological-compare4.C
> b/gcc/testsuite/g++.dg/warn/Wtautological-compare4.C
> new file mode 100644
> index 00000000000..96308f49a42
> --- /dev/null
> +++ b/gcc/testsuite/g++.dg/warn/Wtautological-compare4.C
> @@ -0,0 +1,21 @@
> +// PR c++/116534
> +// { dg-do compile }
> +// { dg-options "-Wall" }
> +
> +template <class A>
> +struct Test {
> + bool foo(unsigned x, unsigned y) {
> + bool test = &a[x] == &b[y];
> + return test;
> + }
> + unsigned *a;
> + unsigned *b;
> +};
> +
> +void
> +g ()
> +{
> + Test<int> t;
> + t.foo (0u, 1u);
> + t.foo (0u, 0u);
> +}
>
> base-commit: cdd5dd2125ca850aa8599f76bed02509590541ef
> --
> 2.46.0
>
Marek
