Combine G_READSTEADYCOUNTER and G_READCYCLECOUNTER rules

Author: vangthao95

llvm/lib/Target/AMDGPU/AMDGPURegBankLegalizeRules.cpp

@@ -913,9 +913,8 @@ RegBankLegalizeRules::RegBankLegalizeRules(const GCNSubtarget &_ST,
 
   addRulesForGOpcs({G_ABS}, Standard).Uni(S16, {{Sgpr32Trunc}, {Sgpr32SExt}});
 
-  addRulesForGOpcs({G_READSTEADYCOUNTER}, Standard).Uni(S64, {{Sgpr64}, {}});
-
-  addRulesForGOpcs({G_READCYCLECOUNTER}).Any({{UniS64}, {{Sgpr64}, {}}});
+  addRulesForGOpcs({G_READSTEADYCOUNTER, G_READCYCLECOUNTER}, Standard)
+      .Uni(S64, {{Sgpr64}, {}});
 
   bool hasSALUFloat = ST->hasSALUFloatInsts();