Re: [Patch] Fortran: Skip bound conv in gfc_conv_gfc_desc_to_cfi_desc with intent(out) ptr [PR108621]

[Harald Anlauf <anlauf@gmx.de>]

Hi Tobias,

Am 24.02.23 um 12:31 schrieb Tobias Burnus:
> (B) The attached patch:
>
> With 'intent(out)' there is no reason to do the conversions. While for
> nullified
> pointers the bounds-conversion loop is skipped, it may still be executed
> for undefined
> pointers. (Which is usually harmless.) In either case, not generating
> this code makes
> sense.
>
> OK for mainline?

LGTM.

I was pondering whether one should keep the testcase closer to the
one in the PR, but the essence of the bug and the fix is well
represented in the reduced version, and also the tree dump tells
the whole story anyway.

> Regarding GCC 12:  I am not really sure as it is no real regression.
> Besides bogus
> warnings, there might be an issue for undefined pointers and
> -fsanitize=undefined, namely
> if 'ubound - lbound' evaluated on random numbers overflows (such as for
> ubound = huge(..)
> and lbound = -huge(..)). But that looks like a rather special case. -
> Thoughts?

I'd rather consider the case of undefined pointers as of practical
importance.  It's up to you or others to decide whether it should
be backported.  I would not oppose.

Thanks for the patch!

Harald

> Tobias
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