[patch] Fix checking failure in IPA-SRA

[Eric Botcazou]

Hi,

this is a regression present on the mainline and 10 branch: on the one hand, 
IPA-SRA does *not* disqualify accesses with zero size but, on the other hand, 
it checks that accesses present in the tree have a (strictly) positive size,
thus trivially yielding an ICE, for example on the attached Ada testcase.

The attached fix relaxes the check, OK for mainline and 10 branch?


2020-12-03  Eric Botcazou  <ebotca...@adacore.com>

        * ipa-sra.c (verify_access_tree_1): Relax assertion on the size.


2020-12-03  Eric Botcazou  <ebotca...@adacore.com>

        * gnat.dg/opt91.ad[sb]: New test.
        * gnat.dg/opt91_pkg.ad[sb]: New helper.

-- 
Eric Botcazou
diff --git a/gcc/ipa-sra.c b/gcc/ipa-sra.c
index 82acc6a21cb..7adc4b688f3 100644
--- a/gcc/ipa-sra.c
+++ b/gcc/ipa-sra.c
@@ -1480,7 +1480,7 @@ verify_access_tree_1 (gensum_param_access *access, HOST_WIDE_INT parent_offset,
 {
   while (access)
     {
-      gcc_assert (access->offset >= 0 && access->size > 0);
+      gcc_assert (access->offset >= 0 && access->size >= 0);
 
       if (parent_size != 0)
 	{

package body Opt91_Pkg is

   package body Pure_Relation is

      overriding function Custom_Image (Self : Rel) return String is
      begin
         return Custom_Image (Self.Rel);
      end Custom_Image;

   end Pure_Relation;

end Opt91_Pkg;

package Opt91_Pkg is

   type Base_Relation is abstract tagged null record;

   function Custom_Image (Self : Base_Relation) return String is abstract;

   generic
      type Ty is private;
      with function Custom_Image (Self : Ty) return String is <>;
   package Pure_Relation is

      type Rel is new Base_Relation with record
         Rel : Ty;
      end record;

      overriding function Custom_Image (Self : Rel) return String;
   end Pure_Relation;

end Opt91_Pkg;

-- { dg-do compile }
-- { dg-options "-O2 -fchecking=1" }

package body Opt91 is

   function Custom_Image (Self : True_Relation_Rec) return String is
   begin
      return "<True>";
   end;

end Opt91;

with Opt91_Pkg; use Opt91_Pkg;

package Opt91 is

   type True_Relation_Rec is null record;
   function Custom_Image (Self : True_Relation_Rec) return String;

   package True_Relation is new Pure_Relation (Ty => True_Relation_Rec);

end Opt91;