/* Return true if INSN requires the stack frame to be set up.
PROLOGUE_USED contains the hard registers used in the function
prologue. SET_UP_BY_PROLOGUE is the set of registers we expect the
prologue to set up for the function. */
bool
requires_stack_frame_p (rtx_insn *insn, HARD_REG_SET prologue_used,
HARD_REG_SET set_up_by_prologue)
{
df_ref def, use;
HARD_REG_SET hardregs;
unsigned regno;
if (CALL_P (insn))
return !SIBLING_CALL_P (insn);
/* We need a frame to get the unique CFA expected by the unwinder. */
if (cfun->can_throw_non_call_exceptions && can_throw_internal (insn))
return true;
CLEAR_HARD_REG_SET (hardregs);
FOR_EACH_INSN_DEF (def, insn)
{
rtx dreg = DF_REF_REG (def);
if (!REG_P (dreg))
continue;
add_to_hard_reg_set (&hardregs, GET_MODE (dreg),
REGNO (dreg));
}
static void
mark_insn (rtx_insn *insn, bool fast)
{
if (!marked_insn_p (insn))
{
if (!fast)
worklist.safe_push (insn);
bitmap_set_bit (marked, INSN_UID (insn));
if (dump_file)
fprintf (dump_file, " Adding insn %d to worklist\n", INSN_UID (insn));
if (CALL_P (insn)
&& !df_in_progress
&& !SIBLING_CALL_P (insn)
&& (RTL_CONST_OR_PURE_CALL_P (insn)
&& !RTL_LOOPING_CONST_OR_PURE_CALL_P (insn)))
find_call_stack_args (as_a <rtx_call_insn *> (insn), true, fast, NULL);
}
}
static bool
deletable_insn_p (rtx_insn *insn, bool fast, bitmap arg_stores)
{
rtx body, x;
int i;
df_ref def;
if (CALL_P (insn)
/* We cannot delete calls inside of the recursive dce because
this may cause basic blocks to be deleted and this messes up
the rest of the stack of optimization passes. */
&& (!df_in_progress)
/* We cannot delete pure or const sibling calls because it is
hard to see the result. */
&& (!SIBLING_CALL_P (insn))
/* We can delete dead const or pure calls as long as they do not
infinite loop. */
&& (RTL_CONST_OR_PURE_CALL_P (insn)
&& !RTL_LOOPING_CONST_OR_PURE_CALL_P (insn)))
return find_call_stack_args (as_a <rtx_call_insn *> (insn), false,
fast, arg_stores);
/* Don't delete jumps, notes and the like. */
if (!NONJUMP_INSN_P (insn))
return false;
/* Don't delete insns that may throw if we cannot do so. */
if (!(cfun->can_delete_dead_exceptions && can_alter_cfg)
&& !insn_nothrow_p (insn))
return false;
/* If INSN sets a global_reg, leave it untouched. */
FOR_EACH_INSN_DEF (def, insn)
if (HARD_REGISTER_NUM_P (DF_REF_REGNO (def))
&& global_regs[DF_REF_REGNO (def)])
return false;
/* Initialization of pseudo PIC register should never be removed. */
else if (DF_REF_REG (def) == pic_offset_table_rtx
&& REGNO (pic_offset_table_rtx) >= FIRST_PSEUDO_REGISTER)
return false;
body = PATTERN (insn);
switch (GET_CODE (body))
{
case USE:
case VAR_LOCATION:
return false;
case CLOBBER:
if (fast)
{
/* A CLOBBER of a dead pseudo register serves no purpose.
That is not necessarily true for hard registers until
after reload. */
x = XEXP (body, 0);
return REG_P (x) && (!HARD_REGISTER_P (x) || reload_completed);
}
else
/* Because of the way that use-def chains are built, it is not
possible to tell if the clobber is dead because it can
never be the target of a use-def chain. */
return false;
case PARALLEL:
for (i = XVECLEN (body, 0) - 1; i >= 0; i--)
if (!deletable_insn_p_1 (XVECEXP (body, 0, i)))
return false;
return true;
default:
return deletable_insn_p_1 (body);
}
}
static basic_block
expand_gimple_tailcall (basic_block bb, tree stmt, bool *can_fallthru)
{
rtx last2, last;
edge e;
edge_iterator ei;
int probability;
gcov_type count;
last2 = last = get_last_insn ();
expand_expr_stmt (stmt);
for (last = NEXT_INSN (last); last; last = NEXT_INSN (last))
if (CALL_P (last) && SIBLING_CALL_P (last))
goto found;
maybe_dump_rtl_for_tree_stmt (stmt, last2);
*can_fallthru = true;
return NULL;
found:
/* ??? Wouldn't it be better to just reset any pending stack adjust?
Any instructions emitted here are about to be deleted. */
do_pending_stack_adjust ();
/* Remove any non-eh, non-abnormal edges that don't go to exit. */
/* ??? I.e. the fallthrough edge. HOWEVER! If there were to be
EH or abnormal edges, we shouldn't have created a tail call in
the first place. So it seems to me we should just be removing
all edges here, or redirecting the existing fallthru edge to
the exit block. */
probability = 0;
count = 0;
for (ei = ei_start (bb->succs); (e = ei_safe_edge (ei)); )
{
if (!(e->flags & (EDGE_ABNORMAL | EDGE_EH)))
{
if (e->dest != EXIT_BLOCK_PTR)
{
e->dest->count -= e->count;
e->dest->frequency -= EDGE_FREQUENCY (e);
if (e->dest->count < 0)
e->dest->count = 0;
if (e->dest->frequency < 0)
e->dest->frequency = 0;
}
count += e->count;
probability += e->probability;
remove_edge (e);
}
else
ei_next (&ei);
}
/* This is somewhat ugly: the call_expr expander often emits instructions
after the sibcall (to perform the function return). These confuse the
find_sub_basic_blocks code, so we need to get rid of these. */
last = NEXT_INSN (last);
gcc_assert (BARRIER_P (last));
*can_fallthru = false;
while (NEXT_INSN (last))
{
/* For instance an sqrt builtin expander expands if with
sibcall in the then and label for `else`. */
if (LABEL_P (NEXT_INSN (last)))
{
*can_fallthru = true;
break;
}
delete_insn (NEXT_INSN (last));
}
e = make_edge (bb, EXIT_BLOCK_PTR, EDGE_ABNORMAL | EDGE_SIBCALL);
e->probability += probability;
e->count += count;
BB_END (bb) = last;
update_bb_for_insn (bb);
if (NEXT_INSN (last))
{
bb = create_basic_block (NEXT_INSN (last), get_last_insn (), bb);
last = BB_END (bb);
if (BARRIER_P (last))
BB_END (bb) = PREV_INSN (last);
}
maybe_dump_rtl_for_tree_stmt (stmt, last2);
return bb;
}
