[Autobackout][FuncReg]Revert of change: e4ec8ed

 Set default VectorAlias to 1

Turn on VectorAlias by default

Author: jgu222

IGC/common/igc_flags.h

@@ -680,7 +680,7 @@ DECLARE_IGC_REGKEY(DWORD, ConstantPromotionCmpSelSize,  4, "Array size threshold
 DECLARE_IGC_REGKEY(bool, FuseResourceLoop,              false, "Enable fusing resource loops", false)
 DECLARE_IGC_REGKEY(bool, EnableVariableReuse,           true, "Enable local variable reuse", false)
 DECLARE_IGC_REGKEY(bool, EnableVariableAlias,           true, "Enable variable aliases (part of VariableReuse Pass, but separate functionality)", false)
-DECLARE_IGC_REGKEY(DWORD, VectorAlias,                     1, "Vector aliasing control under EnableVariableAlias. Some features are still experimental", true)
+DECLARE_IGC_REGKEY(DWORD, VectorAlias,                     0, "Vector aliasing control under EnableVariableAlias. Some features are still experimental", true)
 DECLARE_IGC_REGKEY(bool, EnableExtractMask,             false, "When enabled, it is mostly for reducing response size of send messages.", false)
 DECLARE_IGC_REGKEY(DWORD, VariableReuseByteSize,        64, "The byte size threshold for variable reuse", false)
 DECLARE_IGC_REGKEY(bool, EnableGather4cpoWA,            true, "Enable WA transforming gather4cpo/gather4po into gather4c/gather4", false)