Hi!
OK to push "GCN, RDNA 3: Adjust 'sync_compare_and_swap<mode>_lds_insn'",
see attached?
In pre-RDNA 3 ISA manuals, there are notes for 'DS_CMPST_[...]', like:
Caution, the order of src and cmp are the *opposite* of the
BUFFER_ATOMIC_CMPSWAP opcode.
..., and conversely in the RDNA 3 ISA manual, for 'DS_CMPSTORE_[...]':
In this architecture the order of src and cmp agree with the
BUFFER_ATOMIC_CMPSWAP opcode.
Is my understanding correct, that this isn't something we have to worry
about at the GCC machine description level; that's resolved at the
assembler level?
Grüße
Thomas
>From df6e031bf4b46d9e5b2de117fecd66b8b9b6dd20 Mon Sep 17 00:00:00 2001
From: Thomas Schwinge <[email protected]>
Date: Wed, 31 Jan 2024 10:19:00 +0100
Subject: [PATCH] GCN, RDNA 3: Adjust 'sync_compare_and_swap<mode>_lds_insn'
For OpenACC/GCN '-march=gfx1100', a lot of test cases FAIL:
/tmp/ccGfLJ8a.mkoffload.2.s:406:2: error: instruction not supported on this GPU
ds_cmpst_rtn_b32 v0, v0, v4, v3
^
Apparently, in RDNA 3, 'ds_cmpst_[...]' has been replaced by
'ds_cmpstore_[...]'.
gcc/
* config/gcn/gcn.md (sync_compare_and_swap<mode>_lds_insn)
[TARGET_RDNA3]: Adjust.
---
gcc/config/gcn/gcn.md | 7 ++++++-
1 file changed, 6 insertions(+), 1 deletion(-)
diff --git a/gcc/config/gcn/gcn.md b/gcc/config/gcn/gcn.md
index 8abaef3bbdec..bbb75704140b 100644
--- a/gcc/config/gcn/gcn.md
+++ b/gcc/config/gcn/gcn.md
@@ -2095,7 +2095,12 @@
(match_operand:SIDI 3 "register_operand" " v")]
UNSPECV_ATOMIC))]
""
- "ds_cmpst_rtn_b<bitsize> %0, %1, %2, %3\;s_waitcnt\tlgkmcnt(0)"
+ {
+ if (TARGET_RDNA3)
+ return "ds_cmpstore_rtn_b<bitsize> %0, %1, %2, %3\;s_waitcnt\tlgkmcnt(0)";
+ else
+ return "ds_cmpst_rtn_b<bitsize> %0, %1, %2, %3\;s_waitcnt\tlgkmcnt(0)";
+ }
[(set_attr "type" "ds")
(set_attr "length" "12")])
--
2.43.0
