[llvm] 9890f94 - [AMDGPU][GFX12] Support disassembling MUBUF instructions with arbitrary FORMAT values. (#95243)

[via llvm-commits]

Author: Ivan Kosarev
Date: 2024-06-13T08:16:06+01:00
New Revision: 9890f94343053029000e3ca6ca2b9889755f415a

URL: https://github.com/llvm/llvm-project/commit/9890f94343053029000e3ca6ca2b9889755f415a
DIFF: https://github.com/llvm/llvm-project/commit/9890f94343053029000e3ca6ca2b9889755f415a.diff

LOG: [AMDGPU][GFX12] Support disassembling MUBUF instructions with arbitrary FORMAT values. (#95243)

Some tools generate such instructions with the FORMAT field set to 0,
which corresponds to buf_fmt_invalid, but that should not prevent them
from being recognised on decoding.

Added: 
    

Modified: 
    llvm/lib/Target/AMDGPU/BUFInstructions.td
    llvm/test/MC/Disassembler/AMDGPU/gfx12_dasm_vbuffer_mubuf.txt

Removed: 
    


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diff  --git a/llvm/lib/Target/AMDGPU/BUFInstructions.td b/llvm/lib/Target/AMDGPU/BUFInstructions.td
index 41d4ecaa430f7..01f911c2de5a8 100644
--- a/llvm/lib/Target/AMDGPU/BUFInstructions.td
+++ b/llvm/lib/Target/AMDGPU/BUFInstructions.td
@@ -2454,9 +2454,15 @@ class VBUFFER_Real_gfx12<bits<8> op, BUF_Pseudo ps, string real_name> :
 multiclass VBUFFER_MUBUF_Real_gfx12<bits<8> op, string real_name> {
   defvar ps = !cast<MUBUF_Pseudo>(NAME);
   def _gfx12 : VBUFFER_Real_gfx12<op, ps, real_name> {
-    // Set the last bit of format to 1 to avoid round-trip issues, as some tools
+    // Set the format field to be 1 to avoid round-trip issues, as some tools
     // print BUF_FMT_INVALID for format 0.
-    let Inst{55} = 0b1;
+    let Inst{61-55} = 0b0000001;
+  }
+  // Have a version of the instruction to disassemble to for any other
+  // format field values.
+  def _gfx12_format : VBUFFER_Real<op, ps, real_name> {
+    let AsmVariantName = "NonParsable";
+    let DecoderNamespace = "GFX12";
   }
 }
 

diff  --git a/llvm/test/MC/Disassembler/AMDGPU/gfx12_dasm_vbuffer_mubuf.txt b/llvm/test/MC/Disassembler/AMDGPU/gfx12_dasm_vbuffer_mubuf.txt
index cb3b125041b9f..f2363e774cb9e 100644
--- a/llvm/test/MC/Disassembler/AMDGPU/gfx12_dasm_vbuffer_mubuf.txt
+++ b/llvm/test/MC/Disassembler/AMDGPU/gfx12_dasm_vbuffer_mubuf.txt
@@ -1131,6 +1131,10 @@
 # GFX12: buffer_store_b128 v[1:4], off, s[12:15], s4 offset:8388607 th:TH_STORE_BYPASS scope:SCOPE_SYS ; encoding:  [0x04,0x40,0x07,0xc4,0x01,0x18,0xbc,0x00,0x00,0xff,0xff,0x7f]
 0x04,0x40,0x07,0xc4,0x01,0x18,0xbc,0x00,0x00,0xff,0xff,0x7f
 
+# GFX12: buffer_store_b128 v[5:8], v0, s[20:23], s2 idxen th:TH_STORE_NT_WB scope:SCOPE_DEV ; encoding:  [0x02,0x40,0x07,0xc4,0x05,0x28,0x78,0x80,0x00,0x00,0x00,0x00]
+# Check that we can still disassemble the instruction when the FORMAT field is not 1.
+0x02,0x40,0x07,0xc4,0x05,0x28,0x78,0x80,0x00,0x00,0x00,0x00
+
 # GFX12: buffer_store_d16_format_x v1, off, s[12:15], s4 offset:8388607 ; encoding:  [0x04,0x00,0x03,0xc4,0x01,0x18,0x80,0x00,0x00,0xff,0xff,0x7f]
 0x04,0x00,0x03,0xc4,0x01,0x18,0x80,0x00,0x00,0xff,0xff,0x7f