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Date: Thu, 5 May 2022 09:33:08 -0500
From: Segher Boessenkool <segher@kernel.crashing.org>
To: Alexandre Oliva <oliva@adacore.com>
Cc: gcc-patches@gcc.gnu.org, ebotcazou@libertysurf.fr, vmakarov@redhat.com,
 dje.gcc@gmail.com
Subject: Re: [PATCH] [PR100106] Reject unaligned subregs when strict alignment
 is required
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On Thu, May 05, 2022 at 03:52:01AM -0300, Alexandre Oliva wrote:
> The testcase for pr100106, compiled with optimization for 32-bit
> powerpc -mcpu=604 with -mstrict-align expands the initialization of a
> union from a float _Complex value into a load from an SCmode
> constant pool entry, aligned to 4 bytes, into a DImode pseudo,
> requiring 8-byte alignment.

> +  else if (reg && MEM_P (reg)
> +	   && STRICT_ALIGNMENT && MEM_ALIGN (reg) < GET_MODE_ALIGNMENT (omode))
> +    return false;

Please fix the line breaks?  Either do a break before every &&, or put
as many things as possible on one line?

Note that you should never have paradoxical subregs of mem on rs6000 or
any other target with INSN_SCHEDULING.

> --- /dev/null
> +++ b/gcc/testsuite/gcc.target/powerpc/pr100106-sa.c
> @@ -0,0 +1,4 @@
> +/* { dg-do compile { target { ilp32 } } } */
> +/* { dg-options "-mcpu=604 -O -mstrict-align" } */
> +
> +#include "../../gcc.c-torture/compile/pr100106.c"

It is better to copy the 11 lines of code.

Please comment what the ilp32 is for (namely, the -mcpu= will barf
without it)..  The testcase is okay with those changes, thanks!


Seghr