On Thu, 19 May 2022, Jakub Jelinek wrote:
> Hi!
>
> This is similar to the earlier patch to avoid having MEM_EXPRs
> referencing global vars without varpool nodes, but this time
> the difference is that during gimplification some hashing
> actually created DECL_RTLs for the n VAR_DECL and the previous
> change was in the if above this when DECL_RTL is NULL and we are
> considering creating it.
>
> The following patch drops on the floor references to vars where
> we've optimized away the varpool node even when it has DECL_RTL.
>
> Bootstrapped/regtested on x86_64-linux and i686-linux, plus
> bootstrapped on those without the cfgexpand.cc change, reapplied
> it and rebuilt stage3 cc1/cc1plus, the resulting cc1/cc1plus
> binaries on both targets were identical except for the 16-byte
> executable_checksum (I've done the second bootstraps in the same
> directory as the first one after moving the previous one elsewhere,
> so pathnames were the same, just checksum hasn't been regenerated).
> So, at least on those binaries this patch doesn't affect debug info
> at all.
>
> Ok for trunk?
OK.
Thanks,
Richard.
> 2022-05-19 Jakub Jelinek <ja...@redhat.com>
>
> PR debug/105630
> * cfgexpand.cc (expand_debug_expr): For VAR_DECL, punt for
> global vars without symtab node even when they have DECL_RTL
> set.
>
> * gcc.dg/pr105630.c: New test.
>
> --- gcc/cfgexpand.cc.jj 2022-05-09 09:09:20.005477502 +0200
> +++ gcc/cfgexpand.cc 2022-05-18 13:53:49.622983222 +0200
> @@ -4575,6 +4575,10 @@ expand_debug_expr (tree exp)
> || SYMBOL_REF_DECL (XEXP (op0, 0)) != exp)
> return NULL;
> }
> + else if (VAR_P (exp)
> + && is_global_var (exp)
> + && symtab_node::get (exp) == NULL)
> + return NULL;
> else
> op0 = copy_rtx (op0);
>
> --- gcc/testsuite/gcc.dg/pr105630.c.jj 2022-05-18 14:02:18.426050242
> +0200
> +++ gcc/testsuite/gcc.dg/pr105630.c 2022-05-18 14:02:07.103204525 +0200
> @@ -0,0 +1,22 @@
> +/* PR debug/105630 */
> +/* { dg-do compile { target pthread } } */
> +/* { dg-options "-O1 -ftree-parallelize-loops=2 -fcompare-debug" } */
> +
> +int m;
> +static int n;
> +
> +void
> +foo (void)
> +{
> + int *arr[] = { &n, &n, &n };
> + int unused = n;
> +
> + m = 0;
> +}
> +
> +void
> +bar (int *arr, int i)
> +{
> + while (i < 1)
> + arr[i++] = 1;
> +}
>
> Jakub
>
>
--
Richard Biener <rguent...@suse.de>
SUSE Software Solutions Germany GmbH, Maxfeldstrasse 5, 90409 Nuernberg,
Germany; GF: Ivo Totev, Andrew Myers, Andrew McDonald, Boudien Moerman;
HRB 36809 (AG Nuernberg)
