From: Gary Dismukes <dismukes@adacore.com>
Date: Wed, 8 Jan 2025 22:51:41 +0000 (+0000)
Subject: ada: Unbounded recursion on character aggregates with predicated component subtype
X-Git-Tag: basepoints/gcc-16~2699
X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=c6989fbbf2f195e874245409635a856d74bf6945;p=thirdparty%2Fgcc.git

ada: Unbounded recursion on character aggregates with predicated component subtype

The compiler was recursing endlessly when analyzing an aggregate of
an array type whose component subtype has a static predicate and the
component expressions are static, repeatedly transforming the aggregate
first into a string literal and then back into an aggregate. This is fixed
by suppressing the transformation to a string literal in the case where
the component subtype has predicates.

gcc/ada/ChangeLog:

	* sem_aggr.adb (Resolve_Aggregate): Add another condition to prevent rewriting
	an aggregate whose type is an array of characters, testing for the presence of
	predicates on the component type.
---

diff --git a/gcc/ada/sem_aggr.adb b/gcc/ada/sem_aggr.adb
index 095093cc76b..f6db5cb97a4 100644
--- a/gcc/ada/sem_aggr.adb
+++ b/gcc/ada/sem_aggr.adb
@@ -1382,11 +1382,11 @@ package body Sem_Aggr is
 
          --  Do not perform this transformation if this was a string literal
          --  to start with, whose components needed constraint checks, or if
-         --  the component type is non-static, because it will require those
-         --  checks and be transformed back into an aggregate. If the index
-         --  type is not Integer the aggregate may represent a user-defined
-         --  string type but the context might need the original type so we
-         --  do not perform the transformation at this point.
+         --  the component type is nonstatic or has predicates, because it will
+         --  require those checks and be transformed back into an aggregate.
+         --  If the index type is not Integer, then the aggregate may represent
+         --  a user-defined string type but the context might need the original
+         --  type, so we do not perform the transformation at this point.
 
          if Number_Dimensions (Typ) = 1
            and then Is_Standard_Character_Type (Component_Type (Typ))
@@ -1396,6 +1396,7 @@ package body Sem_Aggr is
            and then not Is_Bit_Packed_Array (Typ)
            and then Nkind (Original_Node (Parent (N))) /= N_String_Literal
            and then Is_OK_Static_Subtype (Component_Type (Typ))
+           and then not Has_Predicates (Component_Type (Typ))
            and then Base_Type (Etype (First_Index (Typ))) =
                       Base_Type (Standard_Integer)
            and then not Has_Static_Empty_Array_Bounds (Typ)