[PATCH] avoid using an incompletely populated struct (PR 100574)

[Jeff Law]

On 5/12/2021 7:55 PM, Martin Sebor via Gcc-patches wrote:
> A logic bug in the handling of PHI arguments in compute_objsize
> that are all null pointers lets an incompletely populated struct
> be used in a way that triggers an assertion causing an ICE.
>
> The attached patch corrects that by having compute_objsize fail
> when the struct isn't fully populated (when all os the PHI's
> arguments are null).
>
> Martin
>
> gcc-100574.diff
>
> PR middle-end/100574 - ICE: in size_remaining, at builtins.c
>
> gcc/ChangeLog:
>
> 	PR middle-end/100574
> 	* builtins.c (access_ref::get_ref): Improve detection of PHIs with
> 	all null arguments.
>
> gcc/testsuite/ChangeLog:
>
> 	PR middle-end/100574
> 	* g++.dg/pr100574.C: New test.

OK

jeff