Re: [PATCH] Fortran: fix PR103390, ICE in gimplification

[Harald Anlauf <anlauf@gmx.de>]

Hi Sandra,

Am 02.01.22 um 19:32 schrieb Sandra Loosemore:
> This patch is for PR103390.  For background on this issue, the Fortran
> standard requires that, when passing a non-contiguous array from Fortran
> to a BIND(C) function with the CONTIGUOUS attribute on the corresponding
> dummy argument, the compiler has to arrange for it to be copied to/from
> a contiguous temporary.  The ICE was happening because the front end was
> attempting to copy out to an array-valued expression that isn't an
> lvalue, and producing invalid code.
>
> I poked around at several related examples (included as test cases in
> the patch) and realized that it should not be doing any copying at all
> here, since the expression result already was being put in a contiguous
> temporary.  And, besides the invalid code on copy-out, in some cases it
> was generating multiple copies of the code to compute the expression on
> copy-in.  :-S
>
> Both parts of the patch seem to be necessary to fix all the test cases.
> Tobias pointed me in this direction when I discussed it with him a few
> weeks ago so I hope I got it right.
>
> OK to check in?  It regression-tests fine on x86_64.

LGTM.

There are a few really minor things to improve:

+	/* TRANPOSE is the only intrinsic that may return a

s/TRANPOSE/TRANSPOSE/

+! We only expect one loop before the call, to fill in the contigous

s/contigous/contiguous/

+! { dg-final { scan-tree-dump-times "contiguous\\.\[0-9\]+" 0
"original" } }

There is a shorter, slightly shorter form for absence of a pattern:

! { dg-final { scan-tree-dump-not "contiguous\\.\[0-9\]+" "original" } }

> -Sandra

Thanks for the patch!