[AMDGPU] Add new aliases ds_subrev_rtn_u32/u64 for ds_rsub_rtn_u32/u64

Following on from llvm#83118, this adds aliases for the "rtn" forms of these
instructions. The fact that they were missing from SP3 was an oversight
which has been fixed now.

Author: jayfoad

llvm/lib/Target/AMDGPU/DSInstructions.td

@@ -1262,7 +1262,9 @@ defm DS_PK_ADD_RTN_BF16   : DS_Real_gfx12<0x0ab>;
 
 // New aliases added in GFX12 without renaming the instructions.
 def : MnemonicAlias<"ds_subrev_u32", "ds_rsub_u32">, Requires<[isGFX12Plus]>;
+def : MnemonicAlias<"ds_subrev_rtn_u32", "ds_rsub_rtn_u32">, Requires<[isGFX12Plus]>;
 def : MnemonicAlias<"ds_subrev_u64", "ds_rsub_u64">, Requires<[isGFX12Plus]>;
+def : MnemonicAlias<"ds_subrev_rtn_u64", "ds_rsub_rtn_u64">, Requires<[isGFX12Plus]>;
 
 //===----------------------------------------------------------------------===//
 // GFX11.

llvm/test/MC/AMDGPU/gfx12_asm_ds_alias.s

@@ -27,5 +27,11 @@ ds_min_rtn_f64 v[5:6], v1, v[2:3]
 ds_subrev_u32 v1, v2
 // GFX12: ds_rsub_u32 v1, v2                      ; encoding: [0x00,0x00,0x08,0xd8,0x01,0x02,0x00,0x00]
 
+ds_subrev_rtn_u32 v5, v1, v2
+// GFX12: ds_rsub_rtn_u32 v5, v1, v2              ; encoding: [0x00,0x00,0x88,0xd8,0x01,0x02,0x00,0x05]
+
 ds_subrev_u64 v1, v[2:3]
 // GFX12: ds_rsub_u64 v1, v[2:3]                  ; encoding: [0x00,0x00,0x08,0xd9,0x01,0x02,0x00,0x00]
+
+ds_subrev_rtn_u64 v[5:6], v1, v[2:3]
+// GFX12: ds_rsub_rtn_u64 v[5:6], v1, v[2:3]      ; encoding: [0x00,0x00,0x88,0xd9,0x01,0x02,0x00,0x05]