[llvm] [AMDGPU] CodeGen for GFX12 S_WAIT_* instructions (PR #77438)

[Pierre van Houtryve via llvm-commits]

================
@@ -905,29 +905,24 @@ class SIInstrInfo final : public AMDGPUGenInstrInfo {
   }
 
   static unsigned getNonSoftWaitcntOpcode(unsigned Opcode) {
-    if (isWaitcnt(Opcode))
+    switch (Opcode) {
+    case AMDGPU::S_WAITCNT_soft:
       return AMDGPU::S_WAITCNT;
-
-    if (isWaitcntVsCnt(Opcode))
+    case AMDGPU::S_WAITCNT_VSCNT_soft:
       return AMDGPU::S_WAITCNT_VSCNT;
-
-    llvm_unreachable("Expected opcode S_WAITCNT/S_WAITCNT_VSCNT");
-  }
-
-  static bool isWaitcnt(unsigned Opcode) {
-    return Opcode == AMDGPU::S_WAITCNT || Opcode == AMDGPU::S_WAITCNT_soft;
-  }
-
-  static bool isWaitcntVsCnt(unsigned Opcode) {
-    return Opcode == AMDGPU::S_WAITCNT_VSCNT ||
-           Opcode == AMDGPU::S_WAITCNT_VSCNT_soft;
-  }
-
-  // "Soft" waitcnt instructions can be relaxed/optimized out by
-  // SIInsertWaitcnts.
-  static bool isSoftWaitcnt(unsigned Opcode) {
-    return Opcode == AMDGPU::S_WAITCNT_soft ||
-           Opcode == AMDGPU::S_WAITCNT_VSCNT_soft;
+    case AMDGPU::S_WAIT_LOADCNT_soft:
+      return AMDGPU::S_WAIT_LOADCNT;
+    case AMDGPU::S_WAIT_STORECNT_soft:
+      return AMDGPU::S_WAIT_STORECNT;
+    case AMDGPU::S_WAIT_SAMPLECNT_soft:
+      return AMDGPU::S_WAIT_SAMPLECNT;
+    case AMDGPU::S_WAIT_BVHCNT_soft:
+      return AMDGPU::S_WAIT_BVHCNT;
+    case AMDGPU::S_WAIT_DSCNT_soft:
+      return AMDGPU::S_WAIT_DSCNT;
+    default:
+      return Opcode;
----------------
Pierre-vh wrote:

Why return the opcode now instead of having an unreachable like before?

https://github.com/llvm/llvm-project/pull/77438