AMDGPU: Add an argument to DS_Real_gfx12 to disable alias, NFC

[changpeng]

This is for cased that we simply want to rename from ps.Mnemonic, but ps.Mnemonic itself is not supported as an alias.

[llvmbot]

@llvm/pr-subscribers-backend-amdgpu

Author: Changpeng Fang (changpeng)

Changes

This is for cased that we simply want to rename from ps.Mnemonic, but ps.Mnemonic itself is not supported as an alias.

---

Full diff: https://github.com/llvm/llvm-project/pull/84717.diff

1 Files Affected:

• (modified) llvm/lib/Target/AMDGPU/DSInstructions.td (+2-2)

diff --git a/llvm/lib/Target/AMDGPU/DSInstructions.td b/llvm/lib/Target/AMDGPU/DSInstructions.td
index a84227ebf506fe..2a02d7f95b3c8c 100644
--- a/llvm/lib/Target/AMDGPU/DSInstructions.td
+++ b/llvm/lib/Target/AMDGPU/DSInstructions.td
@@ -1210,13 +1210,13 @@ class Base_DS_Real_gfx6_gfx7_gfx10_gfx11_gfx12<bits<8> op, DS_Pseudo ps, int ef,
 // GFX12.
 //===----------------------------------------------------------------------===//
 
-multiclass DS_Real_gfx12<bits<8> op, string name = !tolower(NAME)> {
+multiclass DS_Real_gfx12<bits<8> op, string name = !tolower(NAME), int needAlias = true> {
   defvar ps = !cast<DS_Pseudo>(NAME);
   let AssemblerPredicate = isGFX12Plus, DecoderNamespace = "GFX12" in
     def _gfx12 :
       Base_DS_Real_gfx6_gfx7_gfx10_gfx11_gfx12<op, ps, SIEncodingFamily.GFX12,
                                                name, /*hasGDS=*/false>;
-  if !ne(ps.Mnemonic, name) then
+  if !and(needAlias, !ne(ps.Mnemonic, name)) then
     def : MnemonicAlias<ps.Mnemonic, name>, Requires<[isGFX12Plus]>;
 }
 

[arsenm]

Should have some actual uses here?

[jayfoad]

Seems OK assuming you have a need for it downstream.