Re: [PATCH 1/2] gimplefe: Add support for REF_REVERSE_STORAGE_ORDER on mem

> Am 10.08.2026 um 17:45 schrieb Richard Biener <[email protected]>:
> 
> 
> 
>>> Am 10.08.2026 um 17:39 schrieb Andrea Pinski <[email protected]>:
>>> 
>>> On Mon, Aug 10, 2026 at 1:58 AM Richard Biener
>>> <[email protected]> wrote:
>>> 
>>>> On Sun, Aug 9, 2026 at 12:20 AM Andrea Pinski
>>>> <[email protected]> wrote:
>>>> 
>>>> While fixing PR 126729 and PR 126570, I found it was hard
>>>> to figure out if REF_REVERSE_STORAGE_ORDER was set on a MEM_REF.
>>>> Even for the gimple fe was able to set it.
>>>> This adds support to the gimple fe and also outputs
>>>> REF_REVERSE_STORAGE_ORDER for MEM_REF in gimple mode.
>>>> 
>>>> Bootstrapped and tested on x84_64-linux-gnu.
>>>> 
>>>> gcc/c/ChangeLog:
>>>> 
>>>>       * gimple-parser.cc (c_parser_gimple_postfix_expression):
>>>>       Allow for an optional `, 1/0` in front of the cb pair
>>>>       for MEM_REF.
>>>> 
>>>> gcc/ChangeLog:
>>>> 
>>>>       * tree-pretty-print.cc (dump_mem_ref): Dump REF_REVERSE_STORAGE_ORDER
>>>>       if it was set.
>>>> 
>>>> gcc/testsuite/ChangeLog:
>>>> 
>>>>       * gcc.dg/gimplefe-59.c: New test.
>>>> 
>>>> Signed-off-by: Andrea Pinski <[email protected]>
>>>> ---
>>>> gcc/c/gimple-parser.cc             | 34 ++++++++++++++++++++++++++++--
>>>> gcc/testsuite/gcc.dg/gimplefe-59.c | 16 ++++++++++++++
>>>> gcc/tree-pretty-print.cc           |  6 ++++++
>>>> 3 files changed, 54 insertions(+), 2 deletions(-)
>>>> create mode 100644 gcc/testsuite/gcc.dg/gimplefe-59.c
>>>> 
>>>> diff --git a/gcc/c/gimple-parser.cc b/gcc/c/gimple-parser.cc
>>>> index 0fcb9ead83d..59cb29f420c 100644
>>>> --- a/gcc/c/gimple-parser.cc
>>>> +++ b/gcc/c/gimple-parser.cc
>>>> @@ -1530,6 +1530,7 @@ c_parser_gimple_postfix_expression (gimple_parser &parser)
>>>>             /* __MEM '<' type-name [ ',' number ] '>'
>>>>                      '(' [ '(' type-name ')' ] unary-expression
>>>>                          [ '+' number ]
>>>> +                          [ ',' number ]
>>> 
>>> But this breaks existing IL, no?  Also, why a number ... and why in
>>> the deref part?
>> 
>> No it does not break existing IL because the next part contains a `:`
>> in its argument so it is easy to check.
>> The reason for the number is it is easier to parse than anything else
> 
> But a -GIMPLE dump should be as easy to parse than a regular one (did you adjust dumping)?  I don’t like a 0/1 here.
> 
>> 
>>> I'd have expected this to be part of the <type-name ...> part,
>>> alongside the alignment
>>> specification?
>> 
>> Alignment is part of the type while reverse is part of the mem_ref.
>> I know it is a bit odd but that is the current situation we are in.
> 
> Note that we do not have to match 1:1, but I see your point.

IIRC it can also be on a CONPONENT_REF

>> 
>>> 
>>>>                          [ ',' number ':' number ] ')'  */
>>>>             location_t loc = c_parser_peek_token (parser)->location;
>>>>             c_parser_consume_token (parser);
>>>> @@ -1542,6 +1543,8 @@ c_parser_gimple_postfix_expression (gimple_parser &parser)
>>>>             index2.value = NULL_TREE;
>>>>             unsigned short clique = 0;
>>>>             unsigned short base = 0;
>>>> +             bool reverse_order = false;
>>>> +             struct c_expr ro;
>>>>             if (c_parser_require (parser, CPP_OPEN_PAREN, "expected %<(%>"))
>>>>               {
>>>>                 tree alias_type = NULL_TREE;
>>>> @@ -1626,10 +1629,29 @@ c_parser_gimple_postfix_expression (gimple_parser &parser)
>>>>                 if (c_parser_next_token_is (parser, CPP_COMMA))
>>>>                   {
>>>>                     struct c_expr cl, ba;
>>>> +                     bool has_clb = true;
>>>>                     c_parser_consume_token (parser);
>>>>                     cl = c_parser_gimple_postfix_expression (parser);
>>>> -                     if (c_parser_require (parser,
>>>> -                                           CPP_COLON, "expected %<:%>"))
>>>> +                     if (!c_parser_next_token_is (parser, CPP_COLON))
>>>> +                       {
>>>> +                         ro = cl;
>>>> +                         unsigned HOST_WIDE_INT tmp = 0;
>>>> +                         if (!tree_fits_uhwi_p (ro.value)
>>>> +                             || (tmp = tree_to_uhwi (ro.value)) > 1)
>>>> +                           error_at (ro.get_start (),
>>>> +                                     "invalid reverse order value");
>>>> +                         reverse_order = tmp;
>>>> +                         has_clb = false;
>>>> +                         if (c_parser_next_token_is (parser, CPP_COMMA))
>>>> +                           {
>>>> +                             c_parser_consume_token (parser);
>>>> +                             cl = c_parser_gimple_postfix_expression (parser);
>>>> +                             has_clb = true;
>>>> +                           }
>>>> +                       }
>>>> +                     if (has_clb
>>>> +                         && c_parser_require (parser,
>>>> +                                              CPP_COLON, "expected %<:%>"))
>>>>                       {
>>>>                         ba = c_parser_gimple_postfix_expression (parser);
>>>>                         if (!tree_fits_uhwi_p (cl.value)
>>>> @@ -1665,6 +1687,14 @@ c_parser_gimple_postfix_expression (gimple_parser &parser)
>>>>                 MR_DEPENDENCE_CLIQUE (expr.value) = clique;
>>>>                 MR_DEPENDENCE_BASE (expr.value) = base;
>>>>               }
>>>> +             if (reverse_order)
>>>> +               {
>>>> +                 if (TREE_CODE (expr.value) == MEM_REF)
>>>> +                   REF_REVERSE_STORAGE_ORDER (expr.value) = reverse_order;
>>>> +                 else
>>>> +                   error_at (ro.get_start (),
>>>> +                             "target mem ref cannot have reverse order");
>>>> +               }
>>>>             break;
>>>>           }
>>>>         else if (strcmp (IDENTIFIER_POINTER (id), "__VIEW_CONVERT") == 0)
>>>> diff --git a/gcc/testsuite/gcc.dg/gimplefe-59.c b/gcc/testsuite/gcc.dg/gimplefe-59.c
>>>> new file mode 100644
>>>> index 00000000000..296c088a2a0
>>>> --- /dev/null
>>>> +++ b/gcc/testsuite/gcc.dg/gimplefe-59.c
>>>> @@ -0,0 +1,16 @@
>>>> +/* { dg-do compile } */
>>>> +/* { dg-options "-fgimple" } */
>>>> +
>>>> +/* test REF_REVERSE_STORAGE_ORDER parsing of gimple fe. */
>>>> +
>>>> +int __GIMPLE (ssa,guessed_local(1073741824))
>>>> +f2 (void * a, bool b, bool bb)
>>>> +{
>>>> +  int _1;
>>>> +
>>>> +  __BB(2,guessed_local(1073741824)):
>>>> +  _1 = __MEM <int> (a_5(D), 1);
>>>> +  return _1;
>>>> +
>>>> +}
>>>> +
>>>> diff --git a/gcc/tree-pretty-print.cc b/gcc/tree-pretty-print.cc
>>>> index bd60e5c15c1..316945c00ed 100644
>>>> --- a/gcc/tree-pretty-print.cc
>>>> +++ b/gcc/tree-pretty-print.cc
>>>> @@ -2075,6 +2075,12 @@ dump_mem_ref (pretty_printer *pp, tree node, int spc, dump_flags_t flags)
>>>>                                spc, flags | TDF_SLIM, false);
>>>>           }
>>>>       }
>>>> +      if (TREE_CODE (node) == MEM_REF
>>>> +         && REF_REVERSE_STORAGE_ORDER (node))
>>>> +       {
>>>> +         pp_string (pp, ", ");
>>>> +         pp_decimal_int (pp, REF_REVERSE_STORAGE_ORDER (node));
>>>> +       }
>>>>      if (MR_DEPENDENCE_CLIQUE (node) != 0)
>>>>       {
>>>>         pp_string (pp, ", ");
>>>> --
>>>> 2.43.0
>>>>