[llvm] 332b73f - [AMDGPU] Revert wide LDS DMA support.

[Stanislav Mekhanoshin via llvm-commits]

Author: Stanislav Mekhanoshin
Date: 2022-05-16T11:23:35-07:00
New Revision: 332b73fe12c6b383168e03eddd92020d38bc7583

URL: https://github.com/llvm/llvm-project/commit/332b73fe12c6b383168e03eddd92020d38bc7583
DIFF: https://github.com/llvm/llvm-project/commit/332b73fe12c6b383168e03eddd92020d38bc7583.diff

LOG: [AMDGPU] Revert wide LDS DMA support.

This reverts ffbee7acdcaaf, see also bug 37653 which it was fixing.
The bug claims this is an undocumented feature which actually works.
In the reality it is documented as not working for a good reason.
It likely does something, but it is useless anyway. These instructions
write into the LDS. The LDS address is:

M0 + inst_offset + (TIDinWave * 4).

For a store wider than a DWORD neighboring lanes will overwrite each
other.

Differential Revision: https://reviews.llvm.org/D125409

Added: 
    

Modified: 
    llvm/lib/Target/AMDGPU/BUFInstructions.td
    llvm/test/MC/AMDGPU/mubuf.s

Removed: 
    


################################################################################
diff  --git a/llvm/lib/Target/AMDGPU/BUFInstructions.td b/llvm/lib/Target/AMDGPU/BUFInstructions.td
index 6418af0679dc4..91baa472ff519 100644
--- a/llvm/lib/Target/AMDGPU/BUFInstructions.td
+++ b/llvm/lib/Target/AMDGPU/BUFInstructions.td
@@ -954,21 +954,6 @@ defm : MUBUF_Pseudo_Load_Pats<"BUFFER_LOAD_DWORDX2", v2i32, load_global>;
 defm : MUBUF_Pseudo_Load_Pats<"BUFFER_LOAD_DWORDX3", v3i32, load_global>;
 defm : MUBUF_Pseudo_Load_Pats<"BUFFER_LOAD_DWORDX4", v4i32, load_global>;
 
-// This is not described in AMD documentation,
-// but 'lds' versions of these opcodes are available
-// in at least GFX8+ chips. See Bug 37653.
-let SubtargetPredicate = isGFX8GFX9 in {
-defm BUFFER_LOAD_DWORDX2_LDS : MUBUF_Pseudo_Loads <
-  "buffer_load_dwordx2", v2i32, 0, 1
->;
-defm BUFFER_LOAD_DWORDX3_LDS : MUBUF_Pseudo_Loads <
-  "buffer_load_dwordx3", v3i32, 0, 1
->;
-defm BUFFER_LOAD_DWORDX4_LDS : MUBUF_Pseudo_Loads <
-  "buffer_load_dwordx4", v4i32, 0, 1
->;
-}
-
 defm BUFFER_STORE_BYTE : MUBUF_Pseudo_Stores <
   "buffer_store_byte", i32, truncstorei8_global
 >;
@@ -2850,9 +2835,9 @@ defm BUFFER_LOAD_SBYTE          : MUBUF_Real_AllAddr_Lds_vi <0x11>;
 defm BUFFER_LOAD_USHORT         : MUBUF_Real_AllAddr_Lds_vi <0x12>;
 defm BUFFER_LOAD_SSHORT         : MUBUF_Real_AllAddr_Lds_vi <0x13>;
 defm BUFFER_LOAD_DWORD          : MUBUF_Real_AllAddr_Lds_vi <0x14>;
-defm BUFFER_LOAD_DWORDX2        : MUBUF_Real_AllAddr_Lds_vi <0x15>;
-defm BUFFER_LOAD_DWORDX3        : MUBUF_Real_AllAddr_Lds_vi <0x16>;
-defm BUFFER_LOAD_DWORDX4        : MUBUF_Real_AllAddr_Lds_vi <0x17>;
+defm BUFFER_LOAD_DWORDX2        : MUBUF_Real_AllAddr_vi <0x15>;
+defm BUFFER_LOAD_DWORDX3        : MUBUF_Real_AllAddr_vi <0x16>;
+defm BUFFER_LOAD_DWORDX4        : MUBUF_Real_AllAddr_vi <0x17>;
 defm BUFFER_STORE_BYTE          : MUBUF_Real_AllAddr_vi <0x18>;
 defm BUFFER_STORE_BYTE_D16_HI   : MUBUF_Real_AllAddr_vi <0x19>;
 defm BUFFER_STORE_SHORT         : MUBUF_Real_AllAddr_vi <0x1a>;

diff  --git a/llvm/test/MC/AMDGPU/mubuf.s b/llvm/test/MC/AMDGPU/mubuf.s
index f298311f33adb..a1d972aabba04 100644
--- a/llvm/test/MC/AMDGPU/mubuf.s
+++ b/llvm/test/MC/AMDGPU/mubuf.s
@@ -843,18 +843,6 @@ buffer_store_lds_dword s[4:7], s8 offset:4 lds glc slc
 // NOSICI: error: instruction not supported on this GPU
 // VI: buffer_store_lds_dword s[4:7], s8 offset:4 lds glc slc ; encoding: [0x04,0x40,0xf7,0xe0,0x00,0x00,0x01,0x08]
 
-buffer_load_dwordx2 off, s[4:7], s1 lds
-// NOSICI: error: operands are not valid for this GPU or mode
-// VI:   buffer_load_dwordx2 off, s[4:7], s1 lds ; encoding: [0x00,0x00,0x55,0xe0,0x00,0x00,0x01,0x01]
-
-buffer_load_dwordx3 off, s[4:7], s0 offset:4095 lds
-// NOSICI: error: not a valid operand
-// VI:   buffer_load_dwordx3 off, s[4:7], s0 offset:4095 lds ; encoding: [0xff,0x0f,0x59,0xe0,0x00,0x00,0x01,0x00]
-
-buffer_load_dwordx4 off, s[4:7], s1 lds
-// NOSICI: error: operands are not valid for this GPU or mode
-// VI:   buffer_load_dwordx4 off, s[4:7], s1 lds ; encoding: [0x00,0x00,0x5d,0xe0,0x00,0x00,0x01,0x01]
-
 //===----------------------------------------------------------------------===//
 // Errors handling
 //===----------------------------------------------------------------------===//