[Autobackout][FuncReg]Revert of change: 18295b8

Improve support for spill/fill intrinsincs in presence of stack call

Change-Id: Ic1349acb81774e68da67fc50116817be25494439

Author: pratikashar

visa/GraphColor.cpp

@@ -8968,8 +8968,7 @@ int GlobalRA::coloringRegAlloc()
                 }
 #endif
                 bool disableSpillCoalecse = builder.getOption(vISA_DisableSpillCoalescing) ||
-                    builder.getOption(vISA_FastSpill) || builder.getOption(vISA_Debug) ||
-                    !useScratchMsgForSpill;
+                    builder.getOption(vISA_FastSpill) || builder.getOption(vISA_Debug);
                 if (!reserveSpillReg && !disableSpillCoalecse && builder.useSends())
                 {
                     CoalesceSpillFills c(kernel, liveAnalysis, coloring, spillGRF, iterationNo, rpe, *this);

visa/GraphColor.h

@@ -742,11 +742,6 @@ namespace vISA
         // new temps for each reference of spilled address/flag decls
         std::unordered_set<G4_Declare*> addrFlagSpillDcls;
 
-        void expandFillNonStackcall(uint32_t& numRows, uint32_t& offset, short& rowOffset, G4_SrcRegRegion* header, G4_DstRegRegion* resultRgn, G4_BB* bb, INST_LIST_ITER& instIt);
-        void expandSpillNonStackcall(uint32_t& numRows, uint32_t& offset, short& rowOffset, G4_SrcRegRegion* header, G4_SrcRegRegion* payload, G4_BB* bb, INST_LIST_ITER& instIt);
-        void expandFillStackcall(uint32_t& numRows, uint32_t& offset, short& rowOffset, G4_SrcRegRegion* header, G4_DstRegRegion* resultRgn, G4_BB* bb, INST_LIST_ITER& instIt);
-        void expandSpillStackcall(uint32_t& numRows, uint32_t& offset, short& rowOffset, G4_SrcRegRegion* payload, G4_BB* bb, INST_LIST_ITER& instIt);
-
     public:
         G4_Kernel& kernel;
         IR_Builder& builder;

visa/RegAlloc.cpp

@@ -1797,9 +1797,6 @@ bool LivenessAnalysis::writeWholeRegion(G4_BB* bb,
         return false;
     }
 
-    if (inst->isFCall())
-        return true;
-
     // Flags may be partially written when used as the destination
     // e.g., setp (M5_NM, 16) P11 V97(8,0)<0;1,0>
     // It can be only considered as a complete kill