Hi,
For stack_tie, currently below insn is generated:
(insn 15 14 16 3 (parallel [
(set (mem/c:BLK (reg/f:DI 1 1) [1 A8])
(const_int 0 [0]))
]) "/home/guojiufu/temp/gdb.c":13:3 922 {stack_tie}
(nil))
It is "set (mem/c:BLK (reg/f:DI 1 1) (const_int 0 [0])". This maybe
looks like "a memory block is zerored", while actually stack_tie
may be more like a placeholder, and does not generate any thing.
To avoid potential misunderstand, "UNPSEC:BLK [(const_int 0)].." could
be used here.
Compare with previous version, this addes ChangeLog and removes
const_anchor parts.
https://gcc.gnu.org/pipermail/gcc-patches/2023-June/621356.html.
Bootstrap®test pass on ppc64{,le}.
Is this ok for trunk?
BR,
Jeff (Jiufu Guo)
gcc/ChangeLog:
* config/rs6000/predicates.md (tie_operand): Update to match new
stack_tie pattern.
* config/rs6000/rs6000-logue.cc (rs6000_emit_stack_tie): Update to
use the new stack_tie pattern.
* config/rs6000/rs6000.md (UNSPEC_TIE): New UNSPEC.
(restore_stack_block): Update to use the new stack_tie pattern.
(restore_stack_nonlocal): Likewise.
(stack_tie): Update pattern to use UNSPEC_TIE.
(stack_restore_tie): Likewise.
---
gcc/config/rs6000/predicates.md | 11 +++++++----
gcc/config/rs6000/rs6000-logue.cc | 4 +++-
gcc/config/rs6000/rs6000.md | 14 ++++++++++----
4 files changed, 24 insertions(+), 9 deletions(-)
diff --git a/gcc/config/rs6000/predicates.md b/gcc/config/rs6000/predicates.md
index a16ee30f0c0..4748cb37ce8 100644
--- a/gcc/config/rs6000/predicates.md
+++ b/gcc/config/rs6000/predicates.md
@@ -1854,10 +1854,13 @@ (define_predicate "stmw_operation"
(define_predicate "tie_operand"
(match_code "parallel")
{
- return (GET_CODE (XVECEXP (op, 0, 0)) == SET
- && MEM_P (XEXP (XVECEXP (op, 0, 0), 0))
- && GET_MODE (XEXP (XVECEXP (op, 0, 0), 0)) == BLKmode
- && XEXP (XVECEXP (op, 0, 0), 1) == const0_rtx);
+ rtx set = XVECEXP (op, 0, 0);
+ return (GET_CODE (set) == SET
+ && MEM_P (SET_DEST (set))
+ && GET_MODE (SET_DEST (set)) == BLKmode
+ && GET_CODE (SET_SRC (set)) == UNSPEC
+ && XINT (SET_SRC (set), 1) == UNSPEC_TIE
+ && XVECEXP (SET_SRC (set), 0, 0) == const0_rtx);
})
;; Match a small code model toc reference (or medium and large
diff --git a/gcc/config/rs6000/rs6000-logue.cc
b/gcc/config/rs6000/rs6000-logue.cc
index bc6b153b59f..b99f43a8282 100644
--- a/gcc/config/rs6000/rs6000-logue.cc
+++ b/gcc/config/rs6000/rs6000-logue.cc
@@ -1463,7 +1463,9 @@ rs6000_emit_stack_tie (rtx fp, bool hard_frame_needed)
while (--i >= 0)
{
rtx mem = gen_frame_mem (BLKmode, regs[i]);
- RTVEC_ELT (p, i) = gen_rtx_SET (mem, const0_rtx);
+ RTVEC_ELT (p, i)
+ = gen_rtx_SET (mem, gen_rtx_UNSPEC (BLKmode, gen_rtvec (1, const0_rtx),
+ UNSPEC_TIE));
}
emit_insn (gen_stack_tie (gen_rtx_PARALLEL (VOIDmode, p)));
diff --git a/gcc/config/rs6000/rs6000.md b/gcc/config/rs6000/rs6000.md
index b0db8ae508d..fdcf8347812 100644
--- a/gcc/config/rs6000/rs6000.md
+++ b/gcc/config/rs6000/rs6000.md
@@ -158,6 +158,7 @@ (define_c_enum "unspec"
UNSPEC_HASHCHK
UNSPEC_XXSPLTIDP_CONST
UNSPEC_XXSPLTIW_CONST
+ UNSPEC_TIE
])
;;
@@ -10828,7 +10829,9 @@ (define_expand "restore_stack_block"
operands[4] = gen_frame_mem (Pmode, operands[1]);
p = rtvec_alloc (1);
RTVEC_ELT (p, 0) = gen_rtx_SET (gen_frame_mem (BLKmode, operands[0]),
- const0_rtx);
+ gen_rtx_UNSPEC (BLKmode,
+ gen_rtvec (1, const0_rtx),
+ UNSPEC_TIE));
operands[5] = gen_rtx_PARALLEL (VOIDmode, p);
})
@@ -10866,7 +10869,9 @@ (define_expand "restore_stack_nonlocal"
operands[5] = gen_frame_mem (Pmode, operands[3]);
p = rtvec_alloc (1);
RTVEC_ELT (p, 0) = gen_rtx_SET (gen_frame_mem (BLKmode, operands[0]),
- const0_rtx);
+ gen_rtx_UNSPEC (BLKmode,
+ gen_rtvec (1, const0_rtx),
+ UNSPEC_TIE));
operands[6] = gen_rtx_PARALLEL (VOIDmode, p);
})
@@ -13898,7 +13903,8 @@ (define_insn "*save_fpregs_<mode>_r1"
; not be moved over loads from or stores to stack memory.
(define_insn "stack_tie"
[(match_parallel 0 "tie_operand"
- [(set (mem:BLK (reg 1)) (const_int 0))])]
+ [(set (mem:BLK (reg 1))
+ (unspec:BLK [(const_int 0)] UNSPEC_TIE))])]
""
""
[(set_attr "length" "0")])
@@ -13910,7 +13916,7 @@ (define_insn "stack_restore_tie"
[(set (match_operand:SI 0 "gpc_reg_operand" "=r,r")
(plus:SI (match_operand:SI 1 "gpc_reg_operand" "r,r")
(match_operand:SI 2 "reg_or_cint_operand" "O,rI")))
- (set (mem:BLK (scratch)) (const_int 0))]
+ (set (mem:BLK (scratch)) (unspec:BLK [(const_int 0)] UNSPEC_TIE))]
"TARGET_32BIT"
"@
mr %0,%1
--
2.39.3
