/* Combine stack adjustments.
- Copyright (C) 1987-2017 Free Software Foundation, Inc.
+ Copyright (C) 1987-2020 Free Software Foundation, Inc.
This file is part of GCC.
static void free_csa_reflist (struct csa_reflist *);
static struct csa_reflist *record_one_stack_ref (rtx_insn *, rtx *,
struct csa_reflist *);
-static int try_apply_stack_adjustment (rtx_insn *, struct csa_reflist *,
- HOST_WIDE_INT, HOST_WIDE_INT);
-static void combine_stack_adjustments_for_block (basic_block);
+static bool try_apply_stack_adjustment (rtx_insn *, struct csa_reflist *,
+ HOST_WIDE_INT, HOST_WIDE_INT,
+ bitmap, rtx_insn *);
+static void combine_stack_adjustments_for_block (basic_block, bitmap);
/* Main entry point for stack adjustment combination. */
combine_stack_adjustments (void)
{
basic_block bb;
+ bitmap live = BITMAP_ALLOC (®_obstack);
FOR_EACH_BB_FN (bb, cfun)
- combine_stack_adjustments_for_block (bb);
+ combine_stack_adjustments_for_block (bb, live);
+
+ BITMAP_FREE (live);
}
/* Recognize a MEM of the form (sp) or (plus sp const). */
case REG_CFA_SET_VDRAP:
case REG_CFA_WINDOW_SAVE:
case REG_CFA_FLUSH_QUEUE:
+ case REG_CFA_TOGGLE_RA_MANGLE:
return false;
}
as each of the memories and stack references in REFLIST. Return true
on success. */
-static int
+static bool
try_apply_stack_adjustment (rtx_insn *insn, struct csa_reflist *reflist,
- HOST_WIDE_INT new_adjust, HOST_WIDE_INT delta)
+ HOST_WIDE_INT new_adjust, HOST_WIDE_INT delta,
+ bitmap live, rtx_insn *other_insn)
{
struct csa_reflist *ml;
rtx set;
+ bool remove_equal = false;
set = single_set_for_csa (insn);
if (MEM_P (SET_DEST (set)))
validate_change (insn, &SET_DEST (set),
replace_equiv_address (SET_DEST (set), stack_pointer_rtx),
1);
+ else if (REG_P (SET_SRC (set)))
+ {
+ if (other_insn == NULL_RTX || live == NULL)
+ return false;
+ rtx other_set = single_set_for_csa (other_insn);
+ if (SET_DEST (other_set) != stack_pointer_rtx
+ || GET_CODE (SET_SRC (other_set)) != PLUS
+ || XEXP (SET_SRC (other_set), 0) != stack_pointer_rtx
+ || !CONST_INT_P (XEXP (SET_SRC (other_set), 1)))
+ return false;
+ if (PATTERN (other_insn) != other_set)
+ {
+ if (GET_CODE (PATTERN (other_insn)) != PARALLEL)
+ return false;
+ int i;
+ rtx p = PATTERN (other_insn);
+ for (i = 0; i < XVECLEN (p, 0); ++i)
+ {
+ rtx this_rtx = XVECEXP (p, 0, i);
+ if (this_rtx == other_set)
+ continue;
+ if (GET_CODE (this_rtx) != CLOBBER)
+ return false;
+ if (!REG_P (XEXP (this_rtx, 0))
+ || !HARD_REGISTER_P (XEXP (this_rtx, 0)))
+ return false;
+ unsigned int end_regno = END_REGNO (XEXP (this_rtx, 0));
+ for (unsigned int regno = REGNO (XEXP (this_rtx, 0));
+ regno < end_regno; ++regno)
+ if (bitmap_bit_p (live, regno))
+ return false;
+ }
+ }
+ validate_change (insn, &PATTERN (insn), copy_rtx (PATTERN (other_insn)),
+ 1);
+ set = single_set_for_csa (insn);
+ validate_change (insn, &XEXP (SET_SRC (set), 1), GEN_INT (new_adjust),
+ 1);
+ remove_equal = true;
+ }
else
validate_change (insn, &XEXP (SET_SRC (set), 1), GEN_INT (new_adjust), 1);
for (ml = reflist; ml ; ml = ml->next)
ml->sp_offset -= delta;
- return 1;
+ if (remove_equal)
+ remove_reg_equal_equiv_notes (insn);
+ return true;
}
else
- return 0;
+ return false;
}
/* For non-debug insns, record all stack memory references in INSN
/* Subroutine of combine_stack_adjustments, called for each basic block. */
static void
-combine_stack_adjustments_for_block (basic_block bb)
+combine_stack_adjustments_for_block (basic_block bb, bitmap live)
{
HOST_WIDE_INT last_sp_adjust = 0;
rtx_insn *last_sp_set = NULL;
rtx_insn *last2_sp_set = NULL;
+ bitmap last_sp_live = NULL;
struct csa_reflist *reflist = NULL;
+ bitmap copy = NULL;
rtx_insn *insn, *next;
rtx set;
bool end_of_block = false;
+ bitmap_copy (live, DF_LR_IN (bb));
+ df_simulate_initialize_forwards (bb, live);
+
for (insn = BB_HEAD (bb); !end_of_block ; insn = next)
{
end_of_block = insn == BB_END (bb);
continue;
set = single_set_for_csa (insn);
+ if (set && find_reg_note (insn, REG_STACK_CHECK, NULL_RTX))
+ set = NULL_RTX;
if (set)
{
rtx dest = SET_DEST (set);
rtx src = SET_SRC (set);
+ HOST_WIDE_INT this_adjust = 0;
/* 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)))
+ this_adjust = INTVAL (XEXP (src, 1));
+ /* Or such additions turned by postreload into a store of
+ equivalent register. */
+ else if (dest == stack_pointer_rtx
+ && REG_P (src)
+ && REGNO (src) != STACK_POINTER_REGNUM)
+ if (rtx equal = find_reg_note (insn, REG_EQUAL, NULL_RTX))
+ if (GET_CODE (XEXP (equal, 0)) == PLUS
+ && XEXP (XEXP (equal, 0), 0) == stack_pointer_rtx
+ && CONST_INT_P (XEXP (XEXP (equal, 0), 1)))
+ this_adjust = INTVAL (XEXP (XEXP (equal, 0), 1));
+
+ if (this_adjust)
{
- 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;
+ if (REG_P (src))
+ {
+ if (copy == NULL)
+ copy = BITMAP_ALLOC (®_obstack);
+ last_sp_live = copy;
+ bitmap_copy (last_sp_live, live);
+ }
+ else
+ last_sp_live = NULL;
+ df_simulate_one_insn_forwards (bb, insn, live);
continue;
}
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
+ or a deallocation into the second insn. We cannot
combine an allocation followed by a deallocation.
The only somewhat frequent occurrence of the later is when
&& try_apply_stack_adjustment (last_sp_set, reflist,
last_sp_adjust
+ this_adjust,
- this_adjust))
+ this_adjust,
+ last_sp_live,
+ insn))
{
/* It worked! */
maybe_move_args_size_note (last_sp_set, insn, false);
maybe_merge_cfa_adjust (last_sp_set, insn, false);
delete_insn (insn);
last_sp_adjust += this_adjust;
+ last_sp_live = NULL;
continue;
}
}
? last_sp_adjust >= 0 : last_sp_adjust <= 0)
{
if (no_unhandled_cfa (last_sp_set)
+ && !REG_P (src)
&& try_apply_stack_adjustment (insn, reflist,
last_sp_adjust
+ this_adjust,
- -last_sp_adjust))
+ -last_sp_adjust,
+ NULL, NULL))
{
/* 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;
+ last_sp_live = NULL;
free_csa_reflist (reflist);
reflist = NULL;
+ df_simulate_one_insn_forwards (bb, insn, live);
continue;
}
}
reflist = NULL;
last_sp_set = insn;
last_sp_adjust = this_adjust;
+ if (REG_P (src))
+ {
+ if (copy == NULL)
+ copy = BITMAP_ALLOC (®_obstack);
+ last_sp_live = copy;
+ bitmap_copy (last_sp_live, live);
+ }
+ else
+ last_sp_live = NULL;
+ df_simulate_one_insn_forwards (bb, insn, live);
continue;
}
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)))
+ && known_eq (last_sp_adjust,
+ 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))))
+ && known_eq (-last_sp_adjust,
+ GET_MODE_SIZE (GET_MODE (dest)))))
|| ((STACK_GROWS_DOWNWARD
? last_sp_adjust >= 0 : last_sp_adjust <= 0)
&& GET_CODE (XEXP (dest, 0)) == PRE_MODIFY
&& !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))
+ -last_sp_adjust,
+ NULL, NULL))
{
if (last2_sp_set)
maybe_move_args_size_note (last2_sp_set, last_sp_set, false);
reflist = NULL;
last_sp_set = NULL;
last_sp_adjust = 0;
+ last_sp_live = NULL;
+ df_simulate_one_insn_forwards (bb, insn, live);
continue;
}
}
- if (!CALL_P (insn) && last_sp_set
- && record_stack_refs (insn, &reflist))
- continue;
+ if (!CALL_P (insn) && last_sp_set && record_stack_refs (insn, &reflist))
+ {
+ df_simulate_one_insn_forwards (bb, insn, live);
+ continue;
+ }
/* Otherwise, we were not able to process the instruction.
Do not continue collecting data across such a one. */
last2_sp_set = NULL;
last_sp_set = NULL;
last_sp_adjust = 0;
+ last_sp_live = NULL;
}
+
+ df_simulate_one_insn_forwards (bb, insn, live);
}
if (last_sp_set && last_sp_adjust == 0)
if (reflist)
free_csa_reflist (reflist);
+ if (copy)
+ BITMAP_FREE (copy);
}
\f
static unsigned int
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