Hi,
this is a follow-up to
https://gcc.gnu.org/ml/gcc-patches/2012-03/msg01890.html
where Martin was fixing an Ada bootstrap failure on SPARC64. After some
discussion between Martin, Richard B. and me, the initial proposal evolved
into a tweak to be applied to the existing call to set_mem_attributes in the
normal_inner_ref case of expand_expr_real_1, first to avoid it and eventually
to call it on the type instead of the expression.
That was an oversight on my side, since the type is that of the expression and
not that of the value spilled onto the stack, so it may not always be seen as
having an alias set conflicting with that of the expression in Ada, e.g. if
the expression is a an ARRAY_REF of a VCE to an array with a non-aliased
component, see the attached testcase. So the patch reverts the change and
instead clears MEM_EXPR in the problematic case, as first proposed by Martin.
Bootstrapped/regtested on x86_64-suse-linux, OK for mainline and 4.9 branch?
2015-01-14 Eric Botcazou <ebotca...@adacore.com>
* expr.c (expand_expr_real_1) <normal_inner_ref>: Use the expression to
set the memory attributes in all cases but clear MEM_EXPR if need be.
2015-01-14 Eric Botcazou <ebotca...@adacore.com>
* testsuite/gnat.dg/opt47.adb: New test.
--
Eric BotcazouIndex: expr.c
===================================================================
--- expr.c (revision 219578)
+++ expr.c (working copy)
@@ -10137,7 +10137,7 @@ expand_expr_real_1 (tree exp, rtx target
tree tem = get_inner_reference (exp, &bitsize, &bitpos, &offset,
&mode1, &unsignedp, &volatilep, true);
rtx orig_op0, memloc;
- bool mem_attrs_from_type = false;
+ bool clear_mem_expr = false;
/* If we got back the original object, something is wrong. Perhaps
we are evaluating an expression too early. In any event, don't
@@ -10233,7 +10233,7 @@ expand_expr_real_1 (tree exp, rtx target
memloc = assign_temp (TREE_TYPE (tem), 1, 1);
emit_move_insn (memloc, op0);
op0 = memloc;
- mem_attrs_from_type = true;
+ clear_mem_expr = true;
}
if (offset)
@@ -10417,17 +10417,17 @@ expand_expr_real_1 (tree exp, rtx target
if (op0 == orig_op0)
op0 = copy_rtx (op0);
- /* If op0 is a temporary because of forcing to memory, pass only the
- type to set_mem_attributes so that the original expression is never
- marked as ADDRESSABLE through MEM_EXPR of the temporary. */
- if (mem_attrs_from_type)
- set_mem_attributes (op0, type, 0);
- else
- set_mem_attributes (op0, exp, 0);
+ set_mem_attributes (op0, exp, 0);
if (REG_P (XEXP (op0, 0)))
mark_reg_pointer (XEXP (op0, 0), MEM_ALIGN (op0));
+ /* If op0 is a temporary because the original expressions was forced
+ to memory, clear MEM_EXPR so that the original expression cannot
+ be marked as addressable through MEM_EXPR of the temporary. */
+ if (clear_mem_expr)
+ set_mem_expr (op0, NULL_TREE);
+
MEM_VOLATILE_P (op0) |= volatilep;
if (mode == mode1 || mode1 == BLKmode || mode1 == tmode
|| modifier == EXPAND_CONST_ADDRESS
-- { dg-do run }
-- { dg-options "-O2" }
with Ada.Characters.Handling; use Ada.Characters.Handling;
with Interfaces; use Interfaces;
with Ada.Unchecked_Conversion;
procedure Opt47 is
subtype String4 is String (1 .. 4);
function To_String4 is new Ada.Unchecked_Conversion (Unsigned_32, String4);
type Arr is array (Integer range <>) of Unsigned_32;
Leaf : Arr (1 .. 4) := (1349478766, 1948272498, 1702436946, 1702061409);
Value : Unsigned_32;
Result : String (1 .. 32);
Last : Integer := 0;
begin
for I in 1 .. 4 loop
Value := Leaf (I);
for J in reverse String4'Range loop
if Is_Graphic (To_String4 (Value)(J)) then
Last := Last + 1;
Result (Last) := To_String4 (Value)(J);
end if;
end loop;
end loop;
if Result (1) /= 'P' then
raise Program_Error;
end if;
end;
