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Re: [PATCH] PR86844: Fix for store merging


On Tue, Aug 7, 2018 at 1:35 PM Andreas Krebbel <krebbel@linux.ibm.com> wrote:
>
> From: Andreas Krebbel <krebbel@linux.vnet.ibm.com>
>
> Bootstrapped and regtested on s390x and x86_64.

Eric, didn't your patches explicitely handle this case of a non-constant
inbetween?  Can you have a look / review here?

Thanks,
Richard.

> gcc/ChangeLog:
>
> 2018-08-07  Andreas Krebbel  <krebbel@linux.ibm.com>
>
>         PR tree-optimization/86844
>         * gimple-ssa-store-merging.c (check_no_overlap): Add a check to
>         reject overlaps if it has seen a non-constant store in between.
>
> gcc/testsuite/ChangeLog:
>
> 2018-08-07  Andreas Krebbel  <krebbel@linux.ibm.com>
>
>         PR tree-optimization/86844
>         * gcc.dg/pr86844.c: New test.
> ---
>  gcc/gimple-ssa-store-merging.c |  8 +++++++-
>  gcc/testsuite/gcc.dg/pr86844.c | 42 ++++++++++++++++++++++++++++++++++++++++++
>  2 files changed, 49 insertions(+), 1 deletion(-)
>  create mode 100644 gcc/testsuite/gcc.dg/pr86844.c
>
> diff --git a/gcc/gimple-ssa-store-merging.c b/gcc/gimple-ssa-store-merging.c
> index 0ae4581..2abef2e 100644
> --- a/gcc/gimple-ssa-store-merging.c
> +++ b/gcc/gimple-ssa-store-merging.c
> @@ -2401,13 +2401,19 @@ check_no_overlap (vec<store_immediate_info *> m_store_info, unsigned int i,
>                   unsigned HOST_WIDE_INT end)
>  {
>    unsigned int len = m_store_info.length ();
> +  bool seen_group_end_store_p = false;
> +
>    for (++i; i < len; ++i)
>      {
>        store_immediate_info *info = m_store_info[i];
>        if (info->bitpos >= end)
>         break;
> +      if (info->rhs_code != INTEGER_CST)
> +       seen_group_end_store_p = true;
>        if (info->order < last_order
> -         && (rhs_code != INTEGER_CST || info->rhs_code != INTEGER_CST))
> +         && (rhs_code != INTEGER_CST
> +             || info->rhs_code != INTEGER_CST
> +             || seen_group_end_store_p))
>         return false;
>      }
>    return true;
> diff --git a/gcc/testsuite/gcc.dg/pr86844.c b/gcc/testsuite/gcc.dg/pr86844.c
> new file mode 100644
> index 0000000..9ef08e9
> --- /dev/null
> +++ b/gcc/testsuite/gcc.dg/pr86844.c
> @@ -0,0 +1,42 @@
> +/* { dg-do run } */
> +/* { dg-require-effective-target stdint_types } */
> +/* { dg-options "-O1 -fstore-merging" } */
> +
> +#include <stdint.h>
> +
> +struct foo
> +{
> +  union
> +  {
> +    uint32_t u4i;
> +
> +    struct
> +    {
> +      uint8_t x;
> +      uint8_t y;
> +      uint8_t z;
> +      uint8_t w;
> +    } s;
> +  } u;
> +  uint8_t v;
> +};
> +
> +void __attribute__((noinline,noclone))
> +f (struct foo *a)
> +{
> +  a->u.u4i = 0;
> +  a->u.s.w = 222;
> +  a->u.s.y = 129;
> +  a->u.s.z = a->v;
> +}
> +
> +int
> +main ()
> +{
> +  struct foo s;
> +
> +  f (&s);
> +
> +  if (s.u.s.w != 222)
> +    __builtin_abort ();
> +}
> --
> 2.9.1
>


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