fixup! [AMDGPU] SIPeepholeSDWA: Disable on existing SDWA instructions

Author: frederik-h

llvm/lib/Target/AMDGPU/SIPeepholeSDWA.cpp

@@ -962,8 +962,11 @@ bool isConvertibleToSDWA(MachineInstr &MI,
                          const SIInstrInfo* TII) {
   // Check if this is already an SDWA instruction
   unsigned Opc = MI.getOpcode();
-  if (TII->isSDWA(Opc))
+  if (TII->isSDWA(Opc)) {
+    // FIXME: Reenable after fixing selection handling.
+    // Cf. llvm/test/CodeGen/AMDGPU/sdwa-peephole-instr-combine-sel.ll
     return false;
+  }
 
   // Check if this instruction has opcode that supports SDWA
   if (AMDGPU::getSDWAOp(Opc) == -1)