Program correct offset for SIMD16 half-float sampler feedback enable.

Change-Id: I264e2b35b998e71212a3ae75e3b3f382e7e94846

Author: weiyu-chen

IGC/Compiler/CISACodeGen/EmitVISAPass.cpp

@@ -3926,25 +3926,7 @@ void EmitPass::emitLdInstruction(llvm::Instruction* inst)
     {
         if (feedbackEnable)
         {
-            CVariable* flag = m_currShader->GetNewVariable(numLanes(m_currShader->m_dispatchSize), ISA_TYPE_BOOL, EALIGN_BYTE);
-            uint subvar = numLanes(simdSize) / (getGRFSize() >> 2) * 4;
-
-            if (needPacking)
-            {
-                subvar /= 2;
-            }
-
-            m_encoder->SetSrcSubVar(0, subvar);
-            m_encoder->SetSrcRegion(0, 0, 1, 0);
-            CVariable* newdestination = m_currShader->BitCast(dst, ISA_TYPE_UD);
-            m_encoder->SetP(flag, newdestination);
-            m_encoder->Push();
-
-            CVariable* pred = m_currShader->ImmToVariable(0xFFFFFFFF, dst->GetType());
-            CVariable* zero = m_currShader->ImmToVariable(0x0, dst->GetType());
-            m_encoder->SetDstSubVar(subvar);
-            m_encoder->Select(flag, dst, pred, zero);
-            m_encoder->Push();
+            emitFeedbackEnable(false);
         }
 
         if (m_destination->IsUniform())
@@ -6757,6 +6739,31 @@ void EmitPass::emitSurfaceInfo(GenIntrinsicInst* inst)
     ResetVMask(false);
 }
 
+void EmitPass::emitFeedbackEnable(bool isHFPacked)
+{
+    // if feedback is enabled we always return all 4 channels
+    CVariable* flag = m_currShader->GetNewVariable(numLanes(m_currShader->m_dispatchSize), ISA_TYPE_BOOL, EALIGN_BYTE);
+    uint typeSize = CEncoder::GetCISADataTypeSize(m_destination->GetType());
+    uint subvar = (numLanes(m_currShader->m_SIMDSize) * typeSize * 4) / getGRFSize();
+    if (!isHFPacked)
+    {
+        // if HF destination is not packed yet, each channel takes at least 1 GRF.
+        subvar = std::max(4u, subvar);
+    }
+
+    m_encoder->SetSrcSubVar(0, subvar);
+    m_encoder->SetSrcRegion(0, 0, 1, 0);
+    CVariable* newdestination = m_currShader->BitCast(m_destination, ISA_TYPE_UD);
+    m_encoder->SetP(flag, newdestination);
+    m_encoder->Push();
+
+    CVariable* pred = m_currShader->ImmToVariable(0xFFFFFFFF, m_destination->GetType());
+    CVariable* zero = m_currShader->ImmToVariable(0x0, m_destination->GetType());
+    m_encoder->SetDstSubVar(subvar);
+    m_encoder->Select(flag, m_destination, pred, zero);
+    m_encoder->Push();
+}
+
 void EmitPass::emitGather4Instruction(SamplerGatherIntrinsic* inst)
 {
     EOPCODE opCode = GetOpCode(inst);
@@ -6844,28 +6851,9 @@ void EmitPass::emitGather4Instruction(SamplerGatherIntrinsic* inst)
             PackSIMD8HFRet(dst);
         }
 
-
         if (feedbackEnable)
         {
-            CVariable* flag = m_currShader->GetNewVariable(numLanes(m_currShader->m_dispatchSize), ISA_TYPE_BOOL, EALIGN_BYTE);
-            uint subvar = numLanes(m_currShader->m_SIMDSize) / (getGRFSize() >> 2) * 4;
-
-            if (simd8HFRet)
-            {
-                subvar /= 2;
-            }
-
-            m_encoder->SetSrcSubVar(0, subvar);
-            m_encoder->SetSrcRegion(0, 0, 1, 0);
-            CVariable* newdestination = m_currShader->BitCast(m_destination, ISA_TYPE_UD);
-            m_encoder->SetP(flag, newdestination);
-            m_encoder->Push();
-
-            CVariable* pred = m_currShader->ImmToVariable(0xFFFFFFFF, m_destination->GetType());
-            CVariable* zero = m_currShader->ImmToVariable(0x0, m_destination->GetType());
-            m_encoder->SetDstSubVar(subvar);
-            m_encoder->Select(flag, m_destination, pred, zero);
-            m_encoder->Push();
+            emitFeedbackEnable(true);
         }
     }
 }
@@ -6942,25 +6930,7 @@ void EmitPass::emitLdmsInstruction(llvm::Instruction* inst)
 
     if (feedbackEnable)
     {
-        CVariable* flag = m_currShader->GetNewVariable(numLanes(m_currShader->m_dispatchSize), ISA_TYPE_BOOL, EALIGN_BYTE);
-        uint subvar = numLanes(m_currShader->m_SIMDSize) / (getGRFSize() >> 2) * 4;
-
-        if (simd8HFRet)
-        {
-            subvar /= 2;
-        }
-
-        m_encoder->SetSrcSubVar(0, subvar);
-        m_encoder->SetSrcRegion(0, 0, 1, 0);
-        CVariable* newdestination = m_currShader->BitCast(m_destination, ISA_TYPE_UD);
-        m_encoder->SetP(flag, newdestination);
-        m_encoder->Push();
-
-        CVariable* pred = m_currShader->ImmToVariable(0xFFFFFFFF, m_destination->GetType());
-        CVariable* zero = m_currShader->ImmToVariable(0x0, m_destination->GetType());
-        m_encoder->SetDstSubVar(subvar);
-        m_encoder->Select(flag, m_destination, pred, zero);
-        m_encoder->Push();
+        emitFeedbackEnable(true);
     }
 }
 

IGC/Compiler/CISACodeGen/EmitVISAPass.hpp

@@ -648,6 +648,8 @@ namespace IGC
 
         // Helper function to check if A64 WA is required
         bool hasA64WAEnable() const;
+
+        void emitFeedbackEnable(bool isHFPacked);
     };
 
 } // namespace IGC