examine. */
struct insn_chain *reload_insn_chain;
+/* TRUE if we potentially left dead insns in the insn stream and want to
+ run DCE immediately after reload, FALSE otherwise. */
+static bool need_dce;
+
/* List of all insns needing reloads. */
static struct insn_chain *insns_need_reload;
\f
If GLOBAL is zero, we do not have enough information to do that,
so any pseudo reg that is spilled must go to the stack.
- Return value is nonzero if reload failed
- and we must not do any more for this function. */
+ Return value is TRUE if reload likely left dead insns in the
+ stream and a DCE pass should be run to elimiante them. Else the
+ return value is FALSE. */
-int
+bool
reload (rtx first, int global)
{
int i, n;
gcc_assert (bitmap_empty_p (&spilled_pseudos));
- return failure;
+ reload_completed = !failure;
+
+ return need_dce;
}
/* Yet another special case. Unfortunately, reg-stack forces people to
rtx prev = prev_active_insn (insn);
rtx prev_dest;
- /* If the previous insn sets a register that dies in our insn, delete it
- too. */
+ /* If the previous insn sets a register that dies in our insn make
+ a note that we want to run DCE immediately after reload.
+
+ We used to delete the previous insn & recurse, but that's wrong for
+ block local equivalences. Instead of trying to figure out the exact
+ circumstances where we can delete the potentially dead insns, just
+ let DCE do the job. */
if (prev && GET_CODE (PATTERN (prev)) == SET
&& (prev_dest = SET_DEST (PATTERN (prev)), REG_P (prev_dest))
&& reg_mentioned_p (prev_dest, PATTERN (insn))
&& find_regno_note (insn, REG_DEAD, REGNO (prev_dest))
&& ! side_effects_p (SET_SRC (PATTERN (prev))))
- delete_dead_insn (prev);
+ need_dce = 1;
SET_INSN_DELETED (insn);
}
eliminated version of the memory location because push_reload
may do the replacement in certain circumstances. */
if (REG_P (SUBREG_REG (x))
- && (GET_MODE_SIZE (GET_MODE (x))
- <= GET_MODE_SIZE (GET_MODE (SUBREG_REG (x))))
+ && !paradoxical_subreg_p (x)
&& reg_equivs
&& reg_equiv_memory_loc (REGNO (SUBREG_REG (x))) != 0)
{
}
}
}
+
+/* *OP_PTR and *OTHER_PTR are two operands to a conceptual reload.
+ If *OP_PTR is a paradoxical subreg, try to remove that subreg
+ and apply the corresponding narrowing subreg to *OTHER_PTR.
+ Return true if the operands were changed, false otherwise. */
+
+static bool
+strip_paradoxical_subreg (rtx *op_ptr, rtx *other_ptr)
+{
+ rtx op, inner, other, tem;
+
+ op = *op_ptr;
+ if (!paradoxical_subreg_p (op))
+ return false;
+ inner = SUBREG_REG (op);
+
+ other = *other_ptr;
+ tem = gen_lowpart_common (GET_MODE (inner), other);
+ if (!tem)
+ return false;
+
+ /* If the lowpart operation turned a hard register into a subreg,
+ rather than simplifying it to another hard register, then the
+ mode change cannot be properly represented. For example, OTHER
+ might be valid in its current mode, but not in the new one. */
+ if (GET_CODE (tem) == SUBREG
+ && REG_P (other)
+ && HARD_REGISTER_P (other))
+ return false;
+
+ *op_ptr = inner;
+ *other_ptr = tem;
+ return true;
+}
\f
/* A subroutine of reload_as_needed. If INSN has a REG_EH_REGION note,
examine all of the reload insns between PREV and NEXT exclusive, and
{
AND_COMPL_HARD_REG_SET (reg_reloaded_valid, call_used_reg_set);
AND_COMPL_HARD_REG_SET (reg_reloaded_valid, reg_reloaded_call_part_clobbered);
+
+ /* If this is a call to a setjmp-type function, we must not
+ reuse any reload reg contents across the call; that will
+ just be clobbered by other uses of the register in later
+ code, before the longjmp. */
+ if (find_reg_note (insn, REG_SETJMP, NULL_RTX))
+ CLEAR_HARD_REG_SET (reg_reloaded_valid);
}
}
chain reloads or do need an intermediate hard registers. */
bool result = true;
int regno, n, code;
- rtx out, in, tem, insn;
+ rtx out, in, insn;
rtx last = get_last_insn ();
/* Make r2 a component of r1. */
/* If IN is a paradoxical SUBREG, remove it and try to put the
opposite SUBREG on OUT. Likewise for a paradoxical SUBREG on OUT. */
- if (GET_CODE (in) == SUBREG
- && (GET_MODE_SIZE (GET_MODE (in))
- > GET_MODE_SIZE (GET_MODE (SUBREG_REG (in))))
- && (tem = gen_lowpart_common (GET_MODE (SUBREG_REG (in)), out)) != 0)
- in = SUBREG_REG (in), out = tem;
+ strip_paradoxical_subreg (&in, &out);
if (GET_CODE (in) == PLUS
&& (REG_P (XEXP (in, 0))
if (regno >= 0
&& reg_last_reload_reg[regno] != 0
+ && (GET_MODE_SIZE (GET_MODE (reg_last_reload_reg[regno]))
+ >= GET_MODE_SIZE (mode) + byte)
#ifdef CANNOT_CHANGE_MODE_CLASS
/* Verify that the register it's in can be used in
mode MODE. */
{
enum reg_class rclass = rld[r].rclass, last_class;
rtx last_reg = reg_last_reload_reg[regno];
- enum machine_mode need_mode;
i = REGNO (last_reg);
i += subreg_regno_offset (i, GET_MODE (last_reg), byte, mode);
last_class = REGNO_REG_CLASS (i);
- if (byte == 0)
- need_mode = mode;
- else
- need_mode
- = smallest_mode_for_size
- (GET_MODE_BITSIZE (mode) + byte * BITS_PER_UNIT,
- GET_MODE_CLASS (mode) == MODE_PARTIAL_INT
- ? MODE_INT : GET_MODE_CLASS (mode));
-
- if ((GET_MODE_SIZE (GET_MODE (last_reg))
- >= GET_MODE_SIZE (need_mode))
- && reg_reloaded_contents[i] == regno
+ if (reg_reloaded_contents[i] == regno
&& TEST_HARD_REG_BIT (reg_reloaded_valid, i)
&& HARD_REGNO_MODE_OK (i, rld[r].mode)
&& (TEST_HARD_REG_BIT (reg_class_contents[(int) rclass], i)
if (tertiary_icode != CODE_FOR_nothing)
{
rtx third_reloadreg = rld[tertiary_reload].reg_rtx;
- rtx tem;
/* Copy primary reload reg to secondary reload reg.
(Note that these have been swapped above, then
/* If REAL_OLD is a paradoxical SUBREG, remove it
and try to put the opposite SUBREG on
RELOADREG. */
- if (GET_CODE (real_old) == SUBREG
- && (GET_MODE_SIZE (GET_MODE (real_old))
- > GET_MODE_SIZE (GET_MODE (SUBREG_REG (real_old))))
- && 0 != (tem = gen_lowpart_common
- (GET_MODE (SUBREG_REG (real_old)),
- reloadreg)))
- real_old = SUBREG_REG (real_old), reloadreg = tem;
+ strip_paradoxical_subreg (&real_old, &reloadreg);
gen_reload (reloadreg, second_reloadreg,
rl->opnum, rl->when_needed);
/* If IN is a paradoxical SUBREG, remove it and try to put the
opposite SUBREG on OUT. Likewise for a paradoxical SUBREG on OUT. */
- if (GET_CODE (in) == SUBREG
- && (GET_MODE_SIZE (GET_MODE (in))
- > GET_MODE_SIZE (GET_MODE (SUBREG_REG (in))))
- && (tem = gen_lowpart_common (GET_MODE (SUBREG_REG (in)), out)) != 0)
- in = SUBREG_REG (in), out = tem;
- else if (GET_CODE (out) == SUBREG
- && (GET_MODE_SIZE (GET_MODE (out))
- > GET_MODE_SIZE (GET_MODE (SUBREG_REG (out))))
- && (tem = gen_lowpart_common (GET_MODE (SUBREG_REG (out)), in)) != 0)
- out = SUBREG_REG (out), in = tem;
+ if (!strip_paradoxical_subreg (&in, &out))
+ strip_paradoxical_subreg (&out, &in);
/* How to do this reload can get quite tricky. Normally, we are being
asked to reload a simple operand, such as a MEM, a constant, or a pseudo
OSDN Git Service
