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Diffstat (limited to 'gcc/lra-eliminations.cc')
-rw-r--r--gcc/lra-eliminations.cc100
1 files changed, 71 insertions, 29 deletions
diff --git a/gcc/lra-eliminations.cc b/gcc/lra-eliminations.cc
index d84a7d1..9103ef1 100644
--- a/gcc/lra-eliminations.cc
+++ b/gcc/lra-eliminations.cc
@@ -302,15 +302,28 @@ move_plus_up (rtx x)
subreg_lowpart_offset (x_mode,
subreg_reg_mode));
if (cst && CONSTANT_P (cst))
- return gen_rtx_PLUS (x_mode, lowpart_subreg (x_mode,
- XEXP (subreg_reg, 0),
- subreg_reg_mode), cst);
+ {
+ rtx lowpart = lowpart_subreg (x_mode, XEXP (subreg_reg, 0),
+ subreg_reg_mode);
+ if (lowpart)
+ return gen_rtx_PLUS (x_mode, lowpart, cst);
+ }
}
return x;
}
-/* Flag that we already did frame pointer to stack pointer elimination. */
-static bool elimination_fp2sp_occured_p = false;
+/* Flag that we already applied nonzero stack pointer elimination
+ offset; such sp updates cannot currently be undone. */
+static bool elimination_2sp_occurred_p = false;
+
+/* Take note of any nonzero sp-OFFSET used in eliminations to sp. */
+static inline poly_int64
+note_spoff (poly_int64 offset)
+{
+ if (maybe_ne (offset, 0))
+ elimination_2sp_occurred_p = true;
+ return offset;
+}
/* Scan X and replace any eliminable registers (such as fp) with a
replacement (such as sp) if SUBST_P, plus an offset. The offset is
@@ -369,13 +382,10 @@ lra_eliminate_regs_1 (rtx_insn *insn, rtx x, machine_mode mem_mode,
{
rtx to = subst_p ? ep->to_rtx : ep->from_rtx;
- if (ep->to_rtx == stack_pointer_rtx && ep->from == FRAME_POINTER_REGNUM)
- elimination_fp2sp_occured_p = true;
-
if (maybe_ne (update_sp_offset, 0))
{
if (ep->to_rtx == stack_pointer_rtx)
- return plus_constant (Pmode, to, update_sp_offset);
+ return plus_constant (Pmode, to, note_spoff (update_sp_offset));
return to;
}
else if (update_p)
@@ -385,7 +395,8 @@ lra_eliminate_regs_1 (rtx_insn *insn, rtx x, machine_mode mem_mode,
ep->offset
- (insn != NULL_RTX
&& ep->to_rtx == stack_pointer_rtx
- ? lra_get_insn_recog_data (insn)->sp_offset
+ ? note_spoff (lra_get_insn_recog_data
+ (insn)->sp_offset)
: 0));
else
return to;
@@ -402,19 +413,18 @@ lra_eliminate_regs_1 (rtx_insn *insn, rtx x, machine_mode mem_mode,
poly_int64 offset, curr_offset;
rtx to = subst_p ? ep->to_rtx : ep->from_rtx;
- if (ep->to_rtx == stack_pointer_rtx && ep->from == FRAME_POINTER_REGNUM)
- elimination_fp2sp_occured_p = true;
-
if (! update_p && ! full_p)
return simplify_gen_binary (PLUS, Pmode, to, XEXP (x, 1));
if (maybe_ne (update_sp_offset, 0))
- offset = ep->to_rtx == stack_pointer_rtx ? update_sp_offset : 0;
+ offset = (ep->to_rtx == stack_pointer_rtx
+ ? note_spoff (update_sp_offset)
+ : 0);
else
offset = (update_p
? ep->offset - ep->previous_offset : ep->offset);
if (full_p && insn != NULL_RTX && ep->to_rtx == stack_pointer_rtx)
- offset -= lra_get_insn_recog_data (insn)->sp_offset;
+ offset -= note_spoff (lra_get_insn_recog_data (insn)->sp_offset);
if (poly_int_rtx_p (XEXP (x, 1), &curr_offset)
&& known_eq (curr_offset, -offset))
return to;
@@ -465,15 +475,13 @@ lra_eliminate_regs_1 (rtx_insn *insn, rtx x, machine_mode mem_mode,
{
rtx to = subst_p ? ep->to_rtx : ep->from_rtx;
- if (ep->to_rtx == stack_pointer_rtx && ep->from == FRAME_POINTER_REGNUM)
- elimination_fp2sp_occured_p = true;
-
if (maybe_ne (update_sp_offset, 0))
{
if (ep->to_rtx == stack_pointer_rtx)
return plus_constant (Pmode,
gen_rtx_MULT (Pmode, to, XEXP (x, 1)),
- update_sp_offset * INTVAL (XEXP (x, 1)));
+ note_spoff (update_sp_offset)
+ * INTVAL (XEXP (x, 1)));
return gen_rtx_MULT (Pmode, to, XEXP (x, 1));
}
else if (update_p)
@@ -486,7 +494,7 @@ lra_eliminate_regs_1 (rtx_insn *insn, rtx x, machine_mode mem_mode,
poly_int64 offset = ep->offset;
if (insn != NULL_RTX && ep->to_rtx == stack_pointer_rtx)
- offset -= lra_get_insn_recog_data (insn)->sp_offset;
+ offset -= note_spoff (lra_get_insn_recog_data (insn)->sp_offset);
return
plus_constant (Pmode,
gen_rtx_MULT (Pmode, to, XEXP (x, 1)),
@@ -571,6 +579,9 @@ lra_eliminate_regs_1 (rtx_insn *insn, rtx x, machine_mode mem_mode,
case POST_INC:
case PRE_DEC:
case POST_DEC:
+ /* Recurse to adjust elimination offsets in a spilled pseudo. */
+ if (GET_CODE (XEXP (x, 0)) == MEM)
+ break;
/* We do not support elimination of a register that is modified.
elimination_effects has already make sure that this does not
happen. */
@@ -578,6 +589,9 @@ lra_eliminate_regs_1 (rtx_insn *insn, rtx x, machine_mode mem_mode,
case PRE_MODIFY:
case POST_MODIFY:
+ /* Recurse to adjust elimination offsets in a spilled pseudo. */
+ if (GET_CODE (XEXP (x, 0)) == MEM)
+ break;
/* We do not support elimination of a hard register that is
modified. LRA has already make sure that this does not
happen. The only remaining case we need to consider here is
@@ -1172,7 +1186,16 @@ update_reg_eliminate (bitmap insns_with_changed_offsets)
/* If it is a currently used elimination: update the previous
offset. */
if (elimination_map[ep->from] == ep)
- ep->previous_offset = ep->offset;
+ {
+ ep->previous_offset = ep->offset;
+ /* Restore the stack_pointer_rtx into to_rtx, that
+ lra_update_fp2sp_elimination set to from_rtx, so that the assert
+ below still checks what it was supposed to check. */
+ if (ep->from_rtx == ep->to_rtx
+ && ep->from != ep->to
+ && ep->from == FRAME_POINTER_REGNUM)
+ ep->to_rtx = stack_pointer_rtx;
+ }
prev = ep->prev_can_eliminate;
setup_can_eliminate (ep, targetm.can_eliminate (ep->from, ep->to));
@@ -1185,7 +1208,7 @@ update_reg_eliminate (bitmap insns_with_changed_offsets)
setup_can_eliminate (ep, false);
continue;
}
- if (ep->can_eliminate != prev && elimination_map[ep->from] == ep)
+ if (!ep->can_eliminate && elimination_map[ep->from] == ep)
{
/* We cannot use this elimination anymore -- find another
one. */
@@ -1198,8 +1221,7 @@ update_reg_eliminate (bitmap insns_with_changed_offsets)
pointer elimination the condition is a bit relaxed and we just require
that actual elimination has not been done yet. */
gcc_assert (ep->to_rtx != stack_pointer_rtx
- || (ep->from == FRAME_POINTER_REGNUM
- && !elimination_fp2sp_occured_p)
+ || !elimination_2sp_occurred_p
|| (ep->from < FIRST_PSEUDO_REGISTER
&& fixed_regs [ep->from]));
@@ -1414,17 +1436,37 @@ lra_update_fp2sp_elimination (int *spilled_pseudos)
if (frame_pointer_needed || !targetm.frame_pointer_required ())
return 0;
- gcc_assert (!elimination_fp2sp_occured_p);
+ gcc_assert (!elimination_2sp_occurred_p);
+ ep = elimination_map[FRAME_POINTER_REGNUM];
+ if (ep->to == STACK_POINTER_REGNUM)
+ {
+ /* Prevent any further uses of fp, say in spill addresses, from being
+ eliminated to sp and affected by sp offsets. Alas, deactivating the
+ elimination altogether causes the next chosen fp elimination to miss
+ the offset propagation, so it may keep -1 as its prev_offset, and that
+ will make subsequent offsets incorrect. */
+ ep->to_rtx = ep->from_rtx;
+ setup_can_eliminate (ep, false);
+ }
+ else
+ for (ep = reg_eliminate; ep < &reg_eliminate[NUM_ELIMINABLE_REGS]; ep++)
+ if (ep->from == FRAME_POINTER_REGNUM && ep->to == STACK_POINTER_REGNUM)
+ setup_can_eliminate (ep, false);
if (lra_dump_file != NULL)
fprintf (lra_dump_file,
" Frame pointer can not be eliminated anymore\n");
frame_pointer_needed = true;
+ /* If !lra_reg_spill_p, we likely have incomplete range information
+ for pseudos assigned to the frame pointer that will have to be
+ spilled, and so we may end up incorrectly sharing them unless we
+ get live range information for them. */
+ if (lra_complete_live_ranges ())
+ /* If lives ranges changed, update the aggregate live ranges in
+ slots as well before spilling any further pseudos. */
+ lra_recompute_slots_live_ranges ();
CLEAR_HARD_REG_SET (set);
add_to_hard_reg_set (&set, Pmode, HARD_FRAME_POINTER_REGNUM);
n = spill_pseudos (set, spilled_pseudos);
- for (ep = reg_eliminate; ep < &reg_eliminate[NUM_ELIMINABLE_REGS]; ep++)
- if (ep->from == FRAME_POINTER_REGNUM && ep->to == STACK_POINTER_REGNUM)
- setup_can_eliminate (ep, false);
return n;
}
@@ -1464,7 +1506,7 @@ lra_eliminate (bool final_p, bool first_p)
if (first_p)
{
- elimination_fp2sp_occured_p = false;
+ elimination_2sp_occurred_p = false;
init_elimination ();
}
generated by cgit v1.1 at 2025-07-03 01:27:35 +0000