Re: [PATCH v6 1/4] tree-object-size: Support dynamic sizes in conditions

[Jakub Jelinek <jakub@redhat.com>]

On Tue, Jan 11, 2022 at 02:27:47PM +0530, Siddhesh Poyarekar wrote:
> Handle GIMPLE_PHI and conditionals specially for dynamic objects,
> returning PHI/conditional expressions instead of just a MIN/MAX
> estimate.
> 
> This makes the returned object size variable for loops and conditionals,
> so tests need to be adjusted to look for precise size in some cases.
> builtin-dynamic-object-size-5.c had to be modified to only look for
> success in maximum object size case and skip over the minimum object
> size tests because the result is no longer a compile time constant.
> 
> I also added some simple tests to exercise conditionals with dynamic
> object sizes.

Ok, but IMO please fix PR103961 first before committing this patchset.

> gcc/ChangeLog:
> 
> 	* builtins.c (fold_builtin_object_size): Adjust for dynamic size
> 	expressions.
> 	* tree-object-size.c: Include gimplify-me.h.
> 	(struct object_size_info): New member UNKNOWNS.
> 	(size_initval_p, size_usable_p, object_sizes_get_raw): New
> 	functions.
> 	(object_sizes_get): Return suitable gimple variable for
> 	object size.
> 	(bundle_sizes): New function.
> 	(object_sizes_set): Use it and handle dynamic object size
> 	expressions.
> 	(object_sizes_set_temp): New function.
> 	(size_for_offset): Adjust for dynamic size expressions.
> 	(emit_phi_nodes, propagate_unknowns, gimplify_size_expressions):
> 	New functions.
> 	(compute_builtin_object_size): Call gimplify_size_expressions
> 	for OST_DYNAMIC.
> 	(dynamic_object_size): New function.
> 	(cond_expr_object_size): Use it.
> 	(phi_dynamic_object_size): New function.
> 	(collect_object_sizes_for): Call it for OST_DYNAMIC.  Adjust to
> 	accommodate dynamic object sizes.
> 
> gcc/testsuite/ChangeLog:
> 
> 	* gcc.dg/builtin-dynamic-object-size-0.c: New tests.
> 	* gcc.dg/builtin-dynamic-object-size-10.c: Add comment.
> 	* gcc.dg/builtin-dynamic-object-size-5-main.c: New file.
> 	* gcc.dg/builtin-dynamic-object-size-5.c: Use it and change test
> 	to dg-do run.
> 	* gcc.dg/builtin-object-size-5.c [!N]: Define N.
> 	(test1, test2, test3, test4) [__builtin_object_size]: Expect
> 	exact result for __builtin_dynamic_object_size.
> 	* gcc.dg/builtin-object-size-1.c [__builtin_object_size]: Expect
> 	exact size expressions for __builtin_dynamic_object_size.
> 	* gcc.dg/builtin-object-size-2.c [__builtin_object_size]:
> 	Likewise.
> 	* gcc.dg/builtin-object-size-3.c [__builtin_object_size]:
> 	Likewise.
> 	* gcc.dg/builtin-object-size-4.c [__builtin_object_size]:
> 	Likewise.
> 	* gcc.dg/builtin-object-size-5.c [__builtin_object_size]:
> 	Likewise.

	Jakub