PING [PATCH] fix up compute_objsize (including PR 103143)

[Martin Sebor]

Ping for the following cleanup patch:
https://gcc.gnu.org/pipermail/gcc-patches/2021-November/583735.html

On 11/8/21 7:34 PM, Martin Sebor wrote:
> The pointer-query code that implements compute_objsize() that's
> in turn used by most middle end access warnings now has a few
> warts in it and (at least) one bug.  With the exception of
> the bug the warts aren't behind any user-visible bugs that
> I know of but they do cause problems in new code I've been
> implementing on top of it.  Besides fixing the one bug (just
> a typo) the attached patch cleans up these latent issues:
> 
> 1) It moves the bndrng member from the access_ref class to
>     access_data.  As a FIXME in the code notes, the member never
>     did belong in the former and only takes up space in the cache.
> 
> 2) The compute_objsize_r() function is big, unwieldy, and tedious
>     to step through because of all the if statements that are better
>     coded as one switch statement.  This change factors out more
>     of its code into smaller handler functions as has been suggested
>     and done a few times before.
> 
> 3) (2) exposed a few places where I fail to pass the current
>     GIMPLE statement down to ranger.  This leads to worse quality
>     range info, including possible false positives and negatives.
>     I just spotted these problems in code review but I haven't
>     taken the time to come up with test cases.  This change fixes
>     these oversights as well.
> 
> 4) The handling of PHI statements is also in one big, hard-to-
>     follow function.  This change moves the handling of each PHI
>     argument into its own handler which merges it into the previous
>     argument.  This makes the code easier to work with and opens it
>     to reuse also for MIN_EXPR and MAX_EXPR.  (This is primarily
>     used to print informational notes after warnings.)
> 
> 5) Finally, the patch factors code to dump each access_ref
>     cached by the pointer_query cache out of pointer_query::dump
>     and into access_ref::dump.  This helps with debugging.
> 
> These changes should have no user-visible effect and other than
> a regression test for the typo (PR 103143) come with no tests.
> They've been tested on x86_64-linux.
> 
> Martin