Re: [PATCH] SRA: Force gimple operand in an additional corner case (PR 112822)

[Richard Biener <rguenther@suse.de>]

> Am 12.12.2023 um 17:50 schrieb Martin Jambor <mjambor@suse.cz>:
> 
> Hi,
> 
> PR 112822 revealed a corner case in load_assign_lhs_subreplacements
> where it creates invalid gimple: an assignment where on the LHS there
> is a complex variable which however is not a gimple register because
> it has partial defs and on the right hand side there is a
> VIEW_CONVERT_EXPR.  This patch invokes force_gimple_operand_gsi on
> such statements (like it already does when both sides of a generated
> assignment have partial definitions.
> 
> I've made sure the patch passes bootstrap and testsuite on x86_64-linux,
> the bug reporter was kind enough to also check the same on an
> powerpc64le-linux (see bugzilla comment #8).
> 
> The testcase has reasonable size but it is specific to ppc64le and its
> altivec vectors.  My plan is to ask the bug reporter to massage it into
> a target specific testcase in bugzilla.  Alternatively I can try to
> craft a testcase from scratch but that will take time.
> 
> Despite the above, is the patch OK for master?

Ok

Richard 

> 
> Thanks,
> 
> Martin
> 
> 
> 
> gcc/ChangeLog:
> 
> 2023-12-12  Martin Jambor  <mjambor@suse.cz>
> 
>    PR tree-optimization/112822
>    * tree-sra.cc (load_assign_lhs_subreplacements): Invoke
>    force_gimple_operand_gsi also when LHS has partial stores and RHS is a
>    VIEW_CONVERT_EXPR.
> ---
> gcc/tree-sra.cc | 10 +++++++---
> 1 file changed, 7 insertions(+), 3 deletions(-)
> 
> diff --git a/gcc/tree-sra.cc b/gcc/tree-sra.cc
> index 3bd0c7a9af0..99a1b0a6d17 100644
> --- a/gcc/tree-sra.cc
> +++ b/gcc/tree-sra.cc
> @@ -4219,11 +4219,15 @@ load_assign_lhs_subreplacements (struct access *lacc,
>      if (racc && racc->grp_to_be_replaced)
>        {
>          rhs = get_access_replacement (racc);
> +          bool vce = false;
>          if (!useless_type_conversion_p (lacc->type, racc->type))
> -        rhs = fold_build1_loc (sad->loc, VIEW_CONVERT_EXPR,
> -                       lacc->type, rhs);
> +        {
> +          rhs = fold_build1_loc (sad->loc, VIEW_CONVERT_EXPR,
> +                     lacc->type, rhs);
> +          vce = true;
> +        }
> 
> -          if (racc->grp_partial_lhs && lacc->grp_partial_lhs)
> +          if (lacc->grp_partial_lhs && (vce || racc->grp_partial_lhs))
>        rhs = force_gimple_operand_gsi (&sad->old_gsi, rhs, true,
>                        NULL_TREE, true, GSI_SAME_STMT);
>        }
> --
> 2.43.0
>