* tree.c (range_in_array_bounds_p): New predicate.

	* tree.h (range_in_array_bounds_p): Declare it.
	* tree-eh.c (tree_could_trap_p) <ARRAY_RANGE_REF>: Use it to
	return a less conservative answer.
	* tree-sra.c (struct sra_elt): Add new pointer field 'groups'
	and flag 'is_group'.
	(IS_ELEMENT_FOR_GROUP): New macro.
	(FOR_EACH_ACTUAL_CHILD): Likewise.
	(next_child_for_group): New helper function.
	(can_completely_scalarize_p): Take into account groups.
	(sra_hash_tree): Handle RANGE_EXPR.
	(sra_elt_eq): Likewise.
	(lookup_element): Be prepared for handling groups.
	(is_valid_const_index): Delete.
	(maybe_lookup_element_for_expr) <ARRAY_REF>: Use in_array_bounds_p
	instead of is_valid_const_index.
	<ARRAY_RANGE_REF>: New case.
	(sra_walk_expr) <ARRAY_REF>: Use in_array_bounds_p instead of
	is_valid_const_index.
	<ARRAY_RANGE_REF>: Do not unconditionally punt.
	(scan_dump): Dump info for groups too.
	(decide_instantiation_1): Likewise.
	(decide_block_copy): Assert that the element is not a group.
	Propagate decision to groups.
	(generate_one_element_ref): Handle RANGE_EXPR.
	(mark_no_warning): Iterate over actual childs.
	(generate_copy_inout): Likewise.
	(generate_element_copy): Likewise.
	(generate_element_zero): Likewise.
	(generate_element_init_1): Likewise.
	(dump_sra_elt_name): Handle RANGE_EXPR.



git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@115160 138bc75d-0d04-0410-961f-82ee72b054a4

1 files changed, 21 insertions, 0 deletions

diff --git a/gcc/testsuite/gnat.dg/string_slice.adb b/gcc/testsuite/gnat.dg/string_slice.adb
new file mode 100644
index 00000000000..c14ae49b7b7
--- /dev/null
+++ b/gcc/testsuite/gnat.dg/string_slice.adb
@@ -0,0 +1,21 @@
+-- { dg-do run }
+-- { dg-options "-O" }
+
+procedure string_slice is
+
+   subtype Key_T is String (1 .. 3);
+
+   function One_Xkey return Key_T is
+      Key : Key_T := "XXX";
+   begin
+      Key (1 .. 2) := "__";
+      return Key;
+   end;
+
+   Key : Key_T := One_Xkey;
+
+begin
+   if Key (3) /= 'X' then
+      raise Program_Error;
+   end if;
+end;