[Autobackout][FuncReg]Revert of change: 2f0a2a4

Enable RT opt with fix

Change-Id: I3e6616a940b0032c1e15a286ca4b92b1950c6edc

Author: fftzeng

IGC/common/igc_flags.def

@@ -209,7 +209,7 @@ DECLARE_IGC_REGKEY(bool, DisableSendSrcDstOverlapWA,    false, "Disable Send Sou
 DECLARE_IGC_REGKEY(debugString, DisablePassToggles,     0,     "Disable each IGC pass by setting the bit. HEXADECIMAL ONLY!. Ex: C0 is to disable pass 6 and pass 7.", false)
 DECLARE_IGC_REGKEY(bool, ForceStatelessForQueueT,       true,  "In OCL, force to use stateless memory to hold queue_t*. This is a legacy feature to be removed.", false)
 DECLARE_IGC_REGKEY(bool, ForceMemoryFenceBeforeEOT,     false, "Forces inserting SLM or gloabal memory fence before EOT if shader writes to SLM or goblam memory respectively.", false)
-DECLARE_IGC_REGKEY(bool, EnableRTmaskPso,               true,  "Enable render target mask optimization in PSO opt", false)
+DECLARE_IGC_REGKEY(bool, EnableRTmaskPso,               false, "Enable render target mask optimization in PSO opt", false)
 
 DECLARE_IGC_GROUP("Shader dumping")
 DECLARE_IGC_REGKEY(bool, EnableCosDump, false, "Enable cos dump", true)