for gcc/ChangeLog
PR rtl-optimization/120424
* lra-eliminations.cc (elimination_2sp_occurred_p): Rename
from...
(elimination_fp2sp_occured_p): ... this. Adjust all uses.
(lra_eliminate_regs_1): Don't require a from-frame-pointer
elimination to set it.
(update_reg_eliminate): Likewise to test it.
---
gcc/lra-eliminations.cc | 46 +++++++++++++++++++++++++---------------------
1 file changed, 25 insertions(+), 21 deletions(-)
diff --git a/gcc/lra-eliminations.cc b/gcc/lra-eliminations.cc
index 9cdd0c5ff53a2..045f2dcf23ef7 100644
--- a/gcc/lra-eliminations.cc
+++ b/gcc/lra-eliminations.cc
@@ -309,8 +309,18 @@ move_plus_up (rtx x)
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 +379,10 @@ 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 +392,8 @@ 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 +410,18 @@ 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 +472,13 @@ 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 +491,7 @@ 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)),
@@ -1213,8 +1218,7 @@ 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]));
@@ -1429,7 +1433,7 @@ 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)
{
@@ -1499,7 +1503,7 @@ lra_eliminate (bool final_p, bool first_p)
if (first_p)
{
- elimination_fp2sp_occured_p = false;
+ elimination_2sp_occurred_p = false;
init_elimination ();
}
[TESTING] [lra] [x86] require frame pointer on nonzero frame size [PR120424]
FTR, this is what I used to test the above.
diff --git a/gcc/config/i386/i386.cc b/gcc/config/i386/i386.cc
index 84081ab126705..31e0f8a453de9 100644
--- a/gcc/config/i386/i386.cc
+++ b/gcc/config/i386/i386.cc
@@ -6035,6 +6035,11 @@ ix86_frame_pointer_required (void)
if (crtl->profile && !flag_fentry)
return true;
+ /* Exercise lra_update_fp2sp_elimination.
+ Requires -maccumulate-outgoing-args. */
+ if (ix86_get_frame_size ())
+ return true;
+
return false;
}
