Re: [PATCH] c++: Rename metafns_called to state_dependent

On Fri, Jul 31, 2026 at 05:21:17PM +0200, Jakub Jelinek wrote:
> On Thu, Jul 30, 2026 at 10:29:23AM -0400, Jason Merrill wrote:
> > OK, though we might rename metafns_called to something like state_dependent
> > and mention EH in its comment.  That can be a trunk-only followup.
> 
> Here it is, ok for trunk if it passes full bootstrap/regtest?

Looks good to me, and I agree with the renaming.
 
> 2026-07-31  Jakub Jelinek  <[email protected]>
> 
> 	* constexpr.cc (class constexpr_global_ctx): Rename metafns_called
> 	to state_dependent, expand comment about constexpr EH.
> 	(constexpr_global_ctx::constexpr_global_ctx ()): Rename
> 	metafns_called to state_dependent.
> 	(cxx_eval_cxa_builtin_fn): Likewise.
> 	(cxx_eval_call_expression): Likewise.
> 
> --- gcc/cp/constexpr.cc.jj	2026-07-31 08:58:16.466783923 +0200
> +++ gcc/cp/constexpr.cc	2026-07-31 14:54:12.546848510 +0200
> @@ -1221,15 +1221,19 @@ public:
>       class types, etc.  Thus, we need to arrange for calls which call
>       at least some metafunctions to be non-cacheable, because their behavior
>       might not be the same.  Until we figure out which exact metafunctions
> -     need this and which don't, do it for all of them.  */
> -  bool metafns_called;
> +     need this and which don't, do it for all of them.
> +     Also used for some cases in constexpr EH, e.g. __cxa_rethrow,
> +     __builtin_uncaught_exceptions and __builtin_current_exception, which can
> +     be also dependent on some state (pending uncaught or caught exceptions)
> +     not tracked in the constexpr call caching.  */
> +  bool state_dependent;
>  
>    /* Constructor.  */
>    constexpr_global_ctx ()
>      : constexpr_ops_count (0), cleanups (NULL), modifiable (nullptr),
>        consteval_block (NULL_TREE), heap_dealloc_count (0),
>        uncaught_exceptions (0), contract_statement (NULL_TREE),
> -      contract_condition_non_const (false), metafns_called (false) {}
> +      contract_condition_non_const (false), state_dependent (false) {}
>  
>    bool is_outside_lifetime (tree t)
>    {
> @@ -2120,7 +2124,7 @@ cxx_eval_cxa_builtin_fn (const constexpr
>        ++ctx->global->uncaught_exceptions;
>        /* Don't cache calls which rethrow, they depend on the current
>  	 exception which might be caught in the caller.  */
> -      ctx->global->metafns_called = true;
> +      ctx->global->state_dependent = true;
>        *jump_target = arg;
>        return void_node;
>      case CXA_BAD_CAST:
> @@ -2202,7 +2206,7 @@ cxx_eval_cxa_builtin_fn (const constexpr
>        /* Don't cache calls which call __builtin_uncaught_exceptions (),
>  	 they depend on the current uncaught exceptions which might
>  	 be the state from their caller.  */
> -      ctx->global->metafns_called = true;
> +      ctx->global->state_dependent = true;
>        return build_int_cst (integer_type_node,
>  			    ctx->global->uncaught_exceptions);
>      case BUILTIN_CURRENT_EXCEPTION:
> @@ -2257,7 +2261,7 @@ cxx_eval_cxa_builtin_fn (const constexpr
>  	  /* Don't cache calls which call __builtin_current_exception (),
>  	     they depend on the current exception which might be caught
>  	     in the caller.  */
> -	  ctx->global->metafns_called = true;
> +	  ctx->global->state_dependent = true;
>  	  return build_constructor_single (TREE_TYPE (decl), fld, arg);
>  	}
>      case STD_RETHROW_EXCEPTION:
> @@ -4069,7 +4073,7 @@ cxx_eval_call_expression (const constexp
>  	  *non_constant_p = true;
>  	  return t;
>  	}
> -      ctx->global->metafns_called = true;
> +      ctx->global->state_dependent = true;
>        tree e = process_metafunction (ctx, fun, t, non_constant_p, overflow_p,
>  				     jump_target);
>        if (*jump_target)
> @@ -4538,7 +4542,7 @@ cxx_eval_call_expression (const constexp
>  	  call_ctx.call = &new_call;
>  	  unsigned save_heap_alloc_count = ctx->global->heap_vars.length ();
>  	  unsigned save_heap_dealloc_count = ctx->global->heap_dealloc_count;
> -	  bool save_metafns_called = ctx->global->metafns_called;
> +	  bool save_state_dependent = ctx->global->state_dependent;
>  
>  	  /* Make sure we fold std::is_constant_evaluated to true in an
>  	     immediate function.  */
> @@ -4570,7 +4574,7 @@ cxx_eval_call_expression (const constexp
>  		return NULL_TREE;
>  	    }
>  
> -	  ctx->global->metafns_called = false;
> +	  ctx->global->state_dependent = false;
>  
>  	  tree jmp_target = NULL_TREE;
>  	  cxx_eval_constant_expression (&call_ctx, body,
> @@ -4612,9 +4616,9 @@ cxx_eval_call_expression (const constexp
>  		}
>  	    }
>  
> -	  if (ctx->global->metafns_called)
> +	  if (ctx->global->state_dependent)
>  	    cacheable = false;
> -	  ctx->global->metafns_called |= save_metafns_called;
> +	  ctx->global->state_dependent |= save_state_dependent;
>  
>  	  /* At this point, the object's constructor will have run, so
>  	     the object is no longer under construction, and its possible
> 
> 
> 	Jakub
> 

Marek