I suspect codes in prepare_decl_rtl:
case VAR_DECL:
case PARM_DECL:
case RESULT_DECL:
*ws = 0;
obj = *expr_p;
if (DECL_RTL_SET_P (obj))
break;
if (DECL_MODE (obj) == BLKmode)
x = produce_memory_decl_rtl (obj, regno);
else
x = gen_raw_REG (DECL_MODE (obj), (*regno)++);
It generates RTX_REG(regno) for an var_decl which is an array has
DECL_MODE == OImode.
Any suggestions?
On Sun, Apr 28, 2013 at 3:15 PM, Bin.Cheng <[email protected]> wrote:
> Hi,
> Currently tree-ssa-loop-ivopts.c doesn't calculate addr_expr's cost,
> while uses target_spill_cost instead, as in function
> force_expr_to_var_cost. When I experimented with ivopts by calling
> computation_cost to calculate cost of ADDR_EXPR, I encountered assert
> failure in expand_expr_addr_expr_1, because:
> 0) The failure comes with (ADDR_EXPR (ARRAY_REF (local_var_decl)));
> 1) computation_cost calls walk_tree/prepare_decl_rtl to prepare
> RTX_REG for variables in ADDR_EXPR, which is the local_var_decl;
> 2) computation_cost calls expand_expr to do the expanding work.
> 3) function expand_expr_addr_expr_1 returns the RTX_REG as the result
> of expanding, which violates the assertion "gcc_assert (MEM_P
> (result))". The corresponding code in expand_expr_addr_expr_1 is like
> :
>
> default:
> /* If the object is a DECL, then expand it for its rtl. Don't bypass
> expand_expr, as that can have various side effects; LABEL_DECLs for
> example, may not have their DECL_RTL set yet. Expand the rtl of
> CONSTRUCTORs too, which should yield a memory reference for the
> constructor's contents. Assume language specific tree nodes can
> be expanded in some interesting way. */
> gcc_assert (TREE_CODE (exp) < LAST_AND_UNUSED_TREE_CODE);
> if (DECL_P (exp)
> || TREE_CODE (exp) == CONSTRUCTOR
> || TREE_CODE (exp) == COMPOUND_LITERAL_EXPR)
> {
> result = expand_expr (exp, target, tmode,
> modifier == EXPAND_INITIALIZER
> ? EXPAND_INITIALIZER : EXPAND_CONST_ADDRESS);
>
> /* If the DECL isn't in memory, then the DECL wasn't properly
> marked TREE_ADDRESSABLE, which will be either a front-end
> or a tree optimizer bug. */
>
> if (TREE_ADDRESSABLE (exp)
> && ! MEM_P (result)
> && ! targetm.calls.allocate_stack_slots_for_args())
> {
> error ("local frame unavailable (naked function?)");
> return result;
> }
> else
> gcc_assert (MEM_P (result));
> result = XEXP (result, 0);
>
> /* ??? Is this needed anymore? */
> if (DECL_P (exp))
> TREE_USED (exp) = 1;
>
> if (modifier != EXPAND_INITIALIZER
> && modifier != EXPAND_CONST_ADDRESS
> && modifier != EXPAND_SUM)
> result = force_operand (result, target);
> return result;
> }
>
> So the question is
> Is it as expected that cost of ADDR_EXPR cannot be calculated by
> computation_cost? Or the assertion is because of immature
> computation_cost/prepare_decl_rtl?
>
> I am not sure whether I described the problem clearly, please feel
> free to ask for more information. Thanks for your patience.
>
> --
> Best Regards.
--
Best Regards.
