turn on selective-scalarizer flag

Author: Gang Y Chen

IGC/common/igc_flags.def

@@ -291,7 +291,7 @@ DECLARE_IGC_REGKEY(bool, DisableMemOpt2,                false, "Disable MemOpt2"
 DECLARE_IGC_REGKEY(bool, DisablePreRAScheduler,         false, "Disable Pre RA Scheduling", false)
 DECLARE_IGC_REGKEY(DWORD,MaxLiveOutThreshold,           0,     "Max LiveOut Threshold in MemOpt2", false)
 DECLARE_IGC_REGKEY(bool, DisableScalarAtomics,          false, "Disable the Scalar Atomics optimization", false)
-DECLARE_IGC_REGKEY(bool, EnableSelectiveScalarizer,     false, "enable selective scalarizer on GPGPU path", true)
+DECLARE_IGC_REGKEY(bool, EnableSelectiveScalarizer,     true,  "enable selective scalarizer on GPGPU path", true)
 DECLARE_IGC_REGKEY(bool, HoistPSConstBufferValues,      true,  "Hoists up down converts for contant buffer accesses, so they an be vectorized more easily.", false)
 DECLARE_IGC_REGKEY(bool, EnableSingleVertexDispatch,    false, "Vertex Shader Single Patch Dispatch Regkey", false)
 DECLARE_IGC_REGKEY(bool, allowLICM,                     true,  "Enable LICM in IGC.", false)