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[Ada] Remove new strict-alignment check added by AI12-0001

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2019-12-16  Eric Botcazou  <ebotcazou@adacore.com>

gcc/ada/

	* freeze.adb (Check_Strict_Alignment): Remove new check on
	Has_Aliased_Components for array types.

From-SVN: r279433
This commit is contained in:
Eric Botcazou 2019-12-16 10:34:47 +00:00 committed by Pierre-Marie de Rodat
parent c85dda7236
commit 1dcdd961c5
2 changed files with 19 additions and 16 deletions
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5
gcc/ada/ChangeLog
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@ -1,3 +1,8 @@
2019-12-16 Eric Botcazou <ebotcazou@adacore.com>
* freeze.adb (Check_Strict_Alignment): Remove new check on
Has_Aliased_Components for array types.
2019-12-16 Ed Schonberg <schonberg@adacore.com>
* sem_ch4.adb (Try_Container_Indexing): In the case of a derived

30
gcc/ada/freeze.adb
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@ -1614,24 +1614,22 @@ package body Freeze is
Set_Strict_Alignment (E);
elsif Is_Array_Type (E) then
if Has_Aliased_Components (E)
or else Strict_Alignment (Component_Type (E))
then
Set_Strict_Alignment (E);
end if;
Set_Strict_Alignment (E, Strict_Alignment (Component_Type (E)));
-- ??? AI12-001: Any component of a packed type that contains an
-- aliased part must be aligned according to the alignment of its
-- subtype (RM 13.2(7)). This means that the following test:
-- if Has_Aliased_Components (E) then
-- Set_Strict_Alignment (E);
-- end if;
-- should be implemented here. Unfortunately it would break Florist,
-- which has the bad habit of overaligning all the types it declares
-- on 32-bit platforms. Other legacy codebases could also be affected
-- because this check has historically been missing in GNAT.
elsif Is_Record_Type (E) then
-- ??? If the type has convention C_Pass_By_Copy, we consider
-- that it may be packed even if it contains aliased parts.
-- Such types are very unlikely to be misaligned in practice
-- and this makes the compiler accept dubious representation
-- clauses used in Florist on types containing arrays with
-- aliased components.
if C_Pass_By_Copy (E) then
return;
end if;
Comp := First_Component (E);
while Present (Comp) loop
if not Is_Type (Comp)