Turn on SetHasSample for gather4* instructions

HasSample is currently set in emitSampleInstruction() only. This
flag is extended to emitGather4Instruction() as well.

Author: iwwu

IGC/Compiler/CISACodeGen/EmitVISAPass.cpp

@@ -8234,7 +8234,7 @@ void EmitPass::emitSampleInstruction(SampleIntrinsic* inst)
 {
     EOPCODE opCode = GetOpCode(inst);
 
-    m_currShader->m_State.SetHasSample();
+    m_currShader->m_State.SetHasSampleInst();
     ResourceDescriptor resource = GetSampleResourceHelper(inst);
     bool isEval = isUsedOnlyByEval(inst);
     ResourceDescriptor pairedResource = inst->hasPairedTextureArg() && llvm::isa<llvm::UndefValue>(inst->getPairedTextureValue()) == false ?
@@ -8664,6 +8664,7 @@ void EmitPass::emitGather4Instruction(SamplerGatherIntrinsic* inst)
 {
     EOPCODE opCode = GetOpCode(inst);
     uint numOperands = inst->getNumOperands();
+    m_currShader->m_State.SetHasGather4Inst();
 
     //Subtract the offsets, resource and sampler sources to get
     //the number of texture coordinates, src channel select and index to texture source

IGC/Compiler/CISACodeGen/GenericShaderState.hpp

@@ -51,7 +51,8 @@ namespace IGC
         int  GetBarrierNumber() const { return m_BarrierNumber; }
 
         bool GetHasSample() const { return m_HasSample; }
-        void SetHasSample() { m_HasSample = true; }
+        void SetHasSampleInst()  { m_HasSampleInst = true;  m_HasSample = true; }
+        void SetHasGather4Inst() { m_HasGather4Inst = true; m_HasSample = true; }
 
         bool GetHasDPAS() const { return m_HasDPAS; }
         void SetHasDPAS() { m_HasDPAS = true; }
@@ -115,6 +116,8 @@ namespace IGC
         }
     private:
         bool m_HasSample = false;
+        bool m_HasSampleInst = false;
+        bool m_HasGather4Inst = false;
         int m_BarrierNumber = 0;
         bool m_HasDPAS = false;
         // Shader has LSC store messages with non-default L1 cache control