Re: [PATCH] c++: ICE with -Wlogical-op [PR107755]

[Jason Merrill <jason@redhat.com>]

On 1/31/23 15:41, Marek Polacek wrote:
> Here we crash in the middle end because warn_logical_operator calls
> build_range_check which calls various fold_* functions and those
> don't work too well when we're still processing template trees.  For
> instance here we crash because we're converting a RECORD_TYPE to bool.
> At this point VIEW_CONVERT_EXPR<struct Foo>(b) hasn't yet been converted
> to Foo::operator bool (&b).
> 
> I was excited to fix this with instantiation_dependent_expression_p
> which can now be called from c-family/ as well, but the problem isn't
> that the expression is dependent.  So, p_t_d it is.
> 
> Bootstrapped/regtested on x86_64-pc-linux-gnu, ok for trunk?

OK.

> 	PR c++/107755
> 
> gcc/cp/ChangeLog:
> 
> 	* call.cc (build_new_op): Don't call warn_logical_operator when
> 	processing a template.
> 
> gcc/testsuite/ChangeLog:
> 
> 	* g++.dg/warn/Wlogical-op-4.C: New test.
> ---
>   gcc/cp/call.cc                            |  2 +-
>   gcc/testsuite/g++.dg/warn/Wlogical-op-4.C | 23 +++++++++++++++++++++++
>   2 files changed, 24 insertions(+), 1 deletion(-)
>   create mode 100644 gcc/testsuite/g++.dg/warn/Wlogical-op-4.C
> 
> diff --git a/gcc/cp/call.cc b/gcc/cp/call.cc
> index 5715a7cd1de..f7c5d9da94b 100644
> --- a/gcc/cp/call.cc
> +++ b/gcc/cp/call.cc
> @@ -7335,7 +7335,7 @@ build_new_op (const op_location_t &loc, enum tree_code code, int flags,
>       case TRUTH_ORIF_EXPR:
>       case TRUTH_AND_EXPR:
>       case TRUTH_OR_EXPR:
> -      if (complain & tf_warning)
> +      if ((complain & tf_warning) && !processing_template_decl)
>   	warn_logical_operator (loc, code, boolean_type_node,
>   			       code_orig_arg1, arg1,
>   			       code_orig_arg2, arg2);
> diff --git a/gcc/testsuite/g++.dg/warn/Wlogical-op-4.C b/gcc/testsuite/g++.dg/warn/Wlogical-op-4.C
> new file mode 100644
> index 00000000000..745c9117a3d
> --- /dev/null
> +++ b/gcc/testsuite/g++.dg/warn/Wlogical-op-4.C
> @@ -0,0 +1,23 @@
> +// PR c++/107755
> +// { dg-do compile }
> +// { dg-options "-Wlogical-op" }
> +
> +struct Foo
> +{
> +  operator bool() const { return false; }
> +};
> +
> +bool a;
> +Foo b;
> +
> +template <typename ignored>
> +static bool Bar()
> +{
> +  return (true && (false ? a : b));
> +  return (false || (false ? a : b));
> +}
> +
> +bool Baz()
> +{
> +  return Bar<void>();
> +}
> 
> base-commit: b2ec2504af77b35e748067eeb846821d12a6b6b4