Re: [PATCH] expr: Fix up store_expr into SUBREG_PROMOTED_* target [PR108264]

[Richard Biener <rguenther@suse.de>]

> Am 03.01.2023 um 11:34 schrieb Jakub Jelinek via Gcc-patches <gcc-patches@gcc.gnu.org>:
> 
> Hi!
> 
> The following testcase ICEs on s390x-linux (e.g. with -march=z13).
> The problem is that target is (subreg/s/u:SI (reg/v:DI 66 [ x+-4 ]) 4)
> and we call convert_move from temp to the SUBREG_REG of that, expecting
> to extend the value properly.  That works nicely if temp has some
> scalar integer mode (or partial one), but ICEs when temp has V4QImode
> on the assertion that from and to modes have the same bitsize.
> store_expr generally allows say store from V4QI to SI target because
> they have the same size and if temp is a CONST_INT, we already have code
> to convert the constant properly, so the following patch just adds handling
> of non-scalar integer modes by converting them to the mode of target
> first before convert_move extends them.
> 
> Bootstrapped/regtested on x86_64-linux, i686-linux and s390x-linux, ok for
> trunk?

Ok

Richard 

> 2023-01-03  Jakub Jelinek  <jakub@redhat.com>
> 
>    PR middle-end/108264
>    * expr.cc (store_expr): For stores into SUBREG_PROMOTED_* targets
>    from source which doesn't have scalar integral mode first convert
>    it to outer_mode.
> 
>    * gcc.dg/pr108264.c: New test.
> 
> --- gcc/expr.cc.jj    2023-01-02 09:32:23.000000000 +0100
> +++ gcc/expr.cc    2023-01-02 16:48:13.226990815 +0100
> @@ -6226,6 +6226,9 @@ store_expr (tree exp, rtx target, int ca
>      temp = convert_modes (inner_mode, outer_mode, temp,
>                SUBREG_PROMOTED_SIGN (target));
>    }
> +      else if (!SCALAR_INT_MODE_P (GET_MODE (temp)))
> +    temp = convert_modes (outer_mode, TYPE_MODE (TREE_TYPE (exp)),
> +                  temp, SUBREG_PROMOTED_SIGN (target));
> 
>       convert_move (SUBREG_REG (target), temp,
>            SUBREG_PROMOTED_SIGN (target));
> --- gcc/testsuite/gcc.dg/pr108264.c.jj    2023-01-02 17:01:14.865887522 +0100
> +++ gcc/testsuite/gcc.dg/pr108264.c    2023-01-02 17:00:52.238209030 +0100
> @@ -0,0 +1,27 @@
> +/* PR middle-end/108264 */
> +/* { dg-do compile } */
> +/* { dg-options "-O2" } */
> +/* { dg-additional-options "-fpic" { target fpic } } */
> +
> +int v;
> +extern int bar (void);
> +
> +static inline void
> +foo (char *d)
> +{
> +  switch (bar ())
> +    {
> +    case 2:
> +      d[0] = d[1] = d[2] = d[3] = v;
> +      break;
> +    case 4:
> +      d[0] = 0;
> +    }
> +}
> +
> +int
> +baz (int x)
> +{
> +  foo ((char *) &x);
> +  return x;
> +}
> 
>    Jakub
>