bool
default_legitimate_address_p (enum machine_mode mode ATTRIBUTE_UNUSED,
rtx addr ATTRIBUTE_UNUSED,
bool strict ATTRIBUTE_UNUSED)
{
#ifdef GO_IF_LEGITIMATE_ADDRESS
/* Defer to the old implementation using a goto. */
if (strict)
return strict_memory_address_p (mode, addr);
else
return memory_address_p (mode, addr);
#else
gcc_unreachable ();
#endif
}
static bool
propagate_rtx_1 (rtx *px, rtx old_rtx, rtx new_rtx, int flags)
{
rtx x = *px, tem = NULL_RTX, op0, op1, op2;
enum rtx_code code = GET_CODE (x);
machine_mode mode = GET_MODE (x);
machine_mode op_mode;
bool can_appear = (flags & PR_CAN_APPEAR) != 0;
bool valid_ops = true;
if (!(flags & PR_HANDLE_MEM) && MEM_P (x) && !MEM_READONLY_P (x))
{
/* If unsafe, change MEMs to CLOBBERs or SCRATCHes (to preserve whether
they have side effects or not). */
*px = (side_effects_p (x)
? gen_rtx_CLOBBER (GET_MODE (x), const0_rtx)
: gen_rtx_SCRATCH (GET_MODE (x)));
return false;
}
/* If X is OLD_RTX, return NEW_RTX. But not if replacing only within an
address, and we are *not* inside one. */
if (x == old_rtx)
{
*px = new_rtx;
return can_appear;
}
/* If this is an expression, try recursive substitution. */
switch (GET_RTX_CLASS (code))
{
case RTX_UNARY:
op0 = XEXP (x, 0);
op_mode = GET_MODE (op0);
valid_ops &= propagate_rtx_1 (&op0, old_rtx, new_rtx, flags);
if (op0 == XEXP (x, 0))
return true;
tem = simplify_gen_unary (code, mode, op0, op_mode);
break;
case RTX_BIN_ARITH:
case RTX_COMM_ARITH:
op0 = XEXP (x, 0);
op1 = XEXP (x, 1);
valid_ops &= propagate_rtx_1 (&op0, old_rtx, new_rtx, flags);
valid_ops &= propagate_rtx_1 (&op1, old_rtx, new_rtx, flags);
if (op0 == XEXP (x, 0) && op1 == XEXP (x, 1))
return true;
tem = simplify_gen_binary (code, mode, op0, op1);
break;
case RTX_COMPARE:
case RTX_COMM_COMPARE:
op0 = XEXP (x, 0);
op1 = XEXP (x, 1);
op_mode = GET_MODE (op0) != VOIDmode ? GET_MODE (op0) : GET_MODE (op1);
valid_ops &= propagate_rtx_1 (&op0, old_rtx, new_rtx, flags);
valid_ops &= propagate_rtx_1 (&op1, old_rtx, new_rtx, flags);
if (op0 == XEXP (x, 0) && op1 == XEXP (x, 1))
return true;
tem = simplify_gen_relational (code, mode, op_mode, op0, op1);
break;
case RTX_TERNARY:
case RTX_BITFIELD_OPS:
op0 = XEXP (x, 0);
op1 = XEXP (x, 1);
op2 = XEXP (x, 2);
op_mode = GET_MODE (op0);
valid_ops &= propagate_rtx_1 (&op0, old_rtx, new_rtx, flags);
valid_ops &= propagate_rtx_1 (&op1, old_rtx, new_rtx, flags);
valid_ops &= propagate_rtx_1 (&op2, old_rtx, new_rtx, flags);
if (op0 == XEXP (x, 0) && op1 == XEXP (x, 1) && op2 == XEXP (x, 2))
return true;
if (op_mode == VOIDmode)
op_mode = GET_MODE (op0);
tem = simplify_gen_ternary (code, mode, op_mode, op0, op1, op2);
break;
case RTX_EXTRA:
/* The only case we try to handle is a SUBREG. */
if (code == SUBREG)
{
op0 = XEXP (x, 0);
valid_ops &= propagate_rtx_1 (&op0, old_rtx, new_rtx, flags);
if (op0 == XEXP (x, 0))
return true;
tem = simplify_gen_subreg (mode, op0, GET_MODE (SUBREG_REG (x)),
SUBREG_BYTE (x));
}
break;
case RTX_OBJ:
if (code == MEM && x != new_rtx)
{
rtx new_op0;
op0 = XEXP (x, 0);
/* There are some addresses that we cannot work on. */
if (!can_simplify_addr (op0))
return true;
op0 = new_op0 = targetm.delegitimize_address (op0);
valid_ops &= propagate_rtx_1 (&new_op0, old_rtx, new_rtx,
flags | PR_CAN_APPEAR);
/* Dismiss transformation that we do not want to carry on. */
if (!valid_ops
|| new_op0 == op0
|| !(GET_MODE (new_op0) == GET_MODE (op0)
|| GET_MODE (new_op0) == VOIDmode))
return true;
canonicalize_address (new_op0);
/* Copy propagations are always ok. Otherwise check the costs. */
if (!(REG_P (old_rtx) && REG_P (new_rtx))
&& !should_replace_address (op0, new_op0, GET_MODE (x),
MEM_ADDR_SPACE (x),
flags & PR_OPTIMIZE_FOR_SPEED))
return true;
tem = replace_equiv_address_nv (x, new_op0);
}
else if (code == LO_SUM)
{
op0 = XEXP (x, 0);
op1 = XEXP (x, 1);
/* The only simplification we do attempts to remove references to op0
or make it constant -- in both cases, op0's invalidity will not
make the result invalid. */
propagate_rtx_1 (&op0, old_rtx, new_rtx, flags | PR_CAN_APPEAR);
valid_ops &= propagate_rtx_1 (&op1, old_rtx, new_rtx, flags);
if (op0 == XEXP (x, 0) && op1 == XEXP (x, 1))
return true;
/* (lo_sum (high x) x) -> x */
if (GET_CODE (op0) == HIGH && rtx_equal_p (XEXP (op0, 0), op1))
tem = op1;
else
tem = gen_rtx_LO_SUM (mode, op0, op1);
/* OP1 is likely not a legitimate address, otherwise there would have
been no LO_SUM. We want it to disappear if it is invalid, return
false in that case. */
return memory_address_p (mode, tem);
}
else if (code == REG)
{
if (rtx_equal_p (x, old_rtx))
{
*px = new_rtx;
return can_appear;
}
}
break;
default:
break;
}
/* No change, no trouble. */
if (tem == NULL_RTX)
return true;
*px = tem;
/* Allow replacements that simplify operations on a vector or complex
value to a component. The most prominent case is
(subreg ([vec_]concat ...)). */
if (REG_P (tem) && !HARD_REGISTER_P (tem)
&& (VECTOR_MODE_P (GET_MODE (new_rtx))
|| COMPLEX_MODE_P (GET_MODE (new_rtx)))
&& GET_MODE (tem) == GET_MODE_INNER (GET_MODE (new_rtx)))
return true;
/* The replacement we made so far is valid, if all of the recursive
replacements were valid, or we could simplify everything to
a constant. */
return valid_ops || can_appear || CONSTANT_P (tem);
}
static void
combine_stack_adjustments_for_block (basic_block bb)
{
HOST_WIDE_INT last_sp_adjust = 0;
rtx last_sp_set = NULL_RTX;
rtx last2_sp_set = NULL_RTX;
struct csa_reflist *reflist = NULL;
rtx insn, next, set;
struct record_stack_refs_data data;
bool end_of_block = false;
for (insn = BB_HEAD (bb); !end_of_block ; insn = next)
{
end_of_block = insn == BB_END (bb);
next = NEXT_INSN (insn);
if (! INSN_P (insn))
continue;
set = single_set_for_csa (insn);
if (set)
{
rtx dest = SET_DEST (set);
rtx src = SET_SRC (set);
/* Find constant additions to the stack pointer. */
if (dest == stack_pointer_rtx
&& GET_CODE (src) == PLUS
&& XEXP (src, 0) == stack_pointer_rtx
&& CONST_INT_P (XEXP (src, 1)))
{
HOST_WIDE_INT this_adjust = INTVAL (XEXP (src, 1));
/* If we've not seen an adjustment previously, record
it now and continue. */
if (! last_sp_set)
{
last_sp_set = insn;
last_sp_adjust = this_adjust;
continue;
}
/* If not all recorded refs can be adjusted, or the
adjustment is now too large for a constant addition,
we cannot merge the two stack adjustments.
Also we need to be careful to not move stack pointer
such that we create stack accesses outside the allocated
area. We can combine an allocation into the first insn,
or a deallocation into the second insn. We can not
combine an allocation followed by a deallocation.
The only somewhat frequent occurrence of the later is when
a function allocates a stack frame but does not use it.
For this case, we would need to analyze rtl stream to be
sure that allocated area is really unused. This means not
only checking the memory references, but also all registers
or global memory references possibly containing a stack
frame address.
Perhaps the best way to address this problem is to teach
gcc not to allocate stack for objects never used. */
/* Combine an allocation into the first instruction. */
if (STACK_GROWS_DOWNWARD ? this_adjust <= 0 : this_adjust >= 0)
{
if (try_apply_stack_adjustment (last_sp_set, reflist,
last_sp_adjust + this_adjust,
this_adjust))
{
/* It worked! */
maybe_move_args_size_note (last_sp_set, insn, false);
delete_insn (insn);
last_sp_adjust += this_adjust;
continue;
}
}
/* Otherwise we have a deallocation. Do not combine with
a previous allocation. Combine into the second insn. */
else if (STACK_GROWS_DOWNWARD
? last_sp_adjust >= 0 : last_sp_adjust <= 0)
{
if (try_apply_stack_adjustment (insn, reflist,
last_sp_adjust + this_adjust,
-last_sp_adjust))
{
/* It worked! */
maybe_move_args_size_note (insn, last_sp_set, true);
delete_insn (last_sp_set);
last_sp_set = insn;
last_sp_adjust += this_adjust;
free_csa_reflist (reflist);
reflist = NULL;
continue;
}
}
/* Combination failed. Restart processing from here. If
deallocation+allocation conspired to cancel, we can
delete the old deallocation insn. */
if (last_sp_set)
{
if (last_sp_adjust == 0)
{
maybe_move_args_size_note (insn, last_sp_set, true);
delete_insn (last_sp_set);
}
else
last2_sp_set = last_sp_set;
}
free_csa_reflist (reflist);
reflist = NULL;
last_sp_set = insn;
last_sp_adjust = this_adjust;
continue;
}
/* Find a store with pre-(dec|inc)rement or pre-modify of exactly
the previous adjustment and turn it into a simple store. This
is equivalent to anticipating the stack adjustment so this must
be an allocation. */
if (MEM_P (dest)
&& ((STACK_GROWS_DOWNWARD
? (GET_CODE (XEXP (dest, 0)) == PRE_DEC
&& last_sp_adjust
== (HOST_WIDE_INT) GET_MODE_SIZE (GET_MODE (dest)))
: (GET_CODE (XEXP (dest, 0)) == PRE_INC
&& last_sp_adjust
== -(HOST_WIDE_INT) GET_MODE_SIZE (GET_MODE (dest))))
|| ((STACK_GROWS_DOWNWARD
? last_sp_adjust >= 0 : last_sp_adjust <= 0)
&& GET_CODE (XEXP (dest, 0)) == PRE_MODIFY
&& GET_CODE (XEXP (XEXP (dest, 0), 1)) == PLUS
&& XEXP (XEXP (XEXP (dest, 0), 1), 0)
== stack_pointer_rtx
&& GET_CODE (XEXP (XEXP (XEXP (dest, 0), 1), 1))
== CONST_INT
&& INTVAL (XEXP (XEXP (XEXP (dest, 0), 1), 1))
== -last_sp_adjust))
&& XEXP (XEXP (dest, 0), 0) == stack_pointer_rtx
&& !reg_mentioned_p (stack_pointer_rtx, src)
&& memory_address_p (GET_MODE (dest), stack_pointer_rtx)
&& try_apply_stack_adjustment (insn, reflist, 0,
-last_sp_adjust))
{
if (last2_sp_set)
maybe_move_args_size_note (last2_sp_set, last_sp_set, false);
else
maybe_move_args_size_note (insn, last_sp_set, true);
delete_insn (last_sp_set);
free_csa_reflist (reflist);
reflist = NULL;
last_sp_set = NULL_RTX;
last_sp_adjust = 0;
continue;
}
}
data.insn = insn;
data.reflist = reflist;
if (!CALL_P (insn) && last_sp_set
&& !for_each_rtx (&PATTERN (insn), record_stack_refs, &data))
{
reflist = data.reflist;
continue;
}
reflist = data.reflist;
/* Otherwise, we were not able to process the instruction.
Do not continue collecting data across such a one. */
if (last_sp_set
&& (CALL_P (insn)
|| reg_mentioned_p (stack_pointer_rtx, PATTERN (insn))))
{
if (last_sp_set && last_sp_adjust == 0)
{
force_move_args_size_note (bb, last2_sp_set, last_sp_set);
delete_insn (last_sp_set);
}
free_csa_reflist (reflist);
reflist = NULL;
last2_sp_set = NULL_RTX;
last_sp_set = NULL_RTX;
last_sp_adjust = 0;
}
}
if (last_sp_set && last_sp_adjust == 0)
{
force_move_args_size_note (bb, last2_sp_set, last_sp_set);
delete_insn (last_sp_set);
}
if (reflist)
free_csa_reflist (reflist);
}
