decl.c (gnat_to_gnu_entity): Do not turn Ada Pure into GCC const, now implicitely implying nothrow as well.

        ada/
        * decl.c (gnat_to_gnu_entity) <case E_Function>: Do not turn Ada
        Pure into GCC const, now implicitely implying nothrow as well.

        testsuite/
        * gnat.dg/raise_from_pure.ad[bs],
        * gnat.dg/wrap_raise_from_pure.ad[bs]: Support for ...
        * gnat.dg/test_raise_from_pure.adb: New test.

From-SVN: r138509

1 files changed, 6 insertions, 10 deletions

diff --git a/gcc/ada/gcc-interface/decl.c b/gcc/ada/gcc-interface/decl.c
index f7f4a0d..89621db 100644
--- a/gcc/ada/gcc-interface/decl.c
+++ b/gcc/ada/gcc-interface/decl.c
@@ -4025,19 +4025,15 @@ gnat_to_gnu_entity (Entity_Id gnat_entity, tree gnu_expr, int definition)
 	if (TREE_CODE (gnu_return_type) == VOID_TYPE)
 	  pure_flag = false;
 
-	/* The semantics of "pure" in Ada essentially matches that of "const"
-	   in the back-end.  In particular, both properties are orthogonal to
-	   the "nothrow" property.  But this is true only if the EH circuitry
-	   is explicit in the internal representation of the back-end.  If we
-	   are to completely hide the EH circuitry from it, we need to declare
-	   that calls to pure Ada subprograms that can throw have side effects
-	   since they can trigger an "abnormal" transfer of control flow; thus
-	   they can be neither "const" nor "pure" in the back-end sense.  */
+	/* The semantics of "pure" in Ada used to essentially match that of
+	   "const" in the middle-end.  In particular, both properties were
+	   orthogonal to the "nothrow" property.  This is not true in the
+	   middle-end any more and we have no choice but to ignore the hint
+	   at this stage.  */
+
 	gnu_type
 	  = build_qualified_type (gnu_type,
 				  TYPE_QUALS (gnu_type)
-				  | (Exception_Mechanism == Back_End_Exceptions
-				     ? TYPE_QUAL_CONST * pure_flag : 0)
 				  | (TYPE_QUAL_VOLATILE * volatile_flag));
 
 	Sloc_to_locus (Sloc (gnat_entity), &input_location);