Avoid splitting in case of uniform destination

Change-Id: I66b00d95974f7ad09de0471722541933cb190216

Author: priyankarp

IGC/Compiler/CISACodeGen/CISABuilder.cpp

@@ -622,8 +622,8 @@ namespace IGC
 
         unsigned numParts = 0;
         if (NeedSplitting(dst, m_encoderState.m_dstOperand, numParts) ||
-            NeedSplitting(src0, m_encoderState.m_srcOperand[0], numParts, true) ||
-            NeedSplitting(src1, m_encoderState.m_srcOperand[1], numParts, true)) {
+            NeedSplitting(src0, m_encoderState.m_srcOperand[0], numParts, true, dst) ||
+            NeedSplitting(src1, m_encoderState.m_srcOperand[1], numParts, true, dst)) {
 
             VISA_EMask_Ctrl execMask = GetAluEMask(dst);
             VISA_Exec_Size fromExecSize = GetAluExecSize(dst);
@@ -1050,8 +1050,8 @@ namespace IGC
 
         unsigned numParts = 0;
         if (NeedSplitting(dst, m_encoderState.m_dstOperand, numParts) ||
-            NeedSplitting(src0, m_encoderState.m_srcOperand[0], numParts, true) ||
-            NeedSplitting(src1, m_encoderState.m_srcOperand[1], numParts, true)) {
+            NeedSplitting(src0, m_encoderState.m_srcOperand[0], numParts, true, dst) ||
+            NeedSplitting(src1, m_encoderState.m_srcOperand[1], numParts, true, dst)) {
 
             VISA_EMask_Ctrl execMask = GetAluEMask(dst);
             VISA_Exec_Size fromExecSize = GetAluExecSize(dst);
@@ -1097,7 +1097,7 @@ namespace IGC
     // numParts - return the total parts to be split, e.g. if the region spans 4
     // GRFs, it needs splitting into 2 parts at least.
     bool CEncoder::NeedSplitting(CVariable* var, const SModifier& mod,
-        unsigned& numParts, bool isSource) const
+        unsigned& numParts, bool isSource, CVariable* dstVar) const
     {
         // If nothing is specified, don't split.
         if (!var)
@@ -1139,6 +1139,11 @@ namespace IGC
             return false;
         }
 
+        // Avoid splitting if destination is uniform and is not an indirect address
+        if (dstVar && !GetAluExecSize(dstVar)) {
+            return false;
+        }
+
         // We assume there is no 2 GRF crossing when element size is smaller than
         // 4 bytes (or 32 bits), e.g. 16-bit WORD.
         if (elemSize < 4)
@@ -1566,8 +1571,9 @@ namespace IGC
                 }
             }
             unsigned numParts = 0;
-            if (NeedSplitting(dst, m_encoderState.m_dstOperand, numParts) ||
-                NeedSplitting(src, m_encoderState.m_srcOperand[0], numParts, true)) {
+
+            if ((NeedSplitting(dst, m_encoderState.m_dstOperand, numParts)) ||
+                NeedSplitting(src, m_encoderState.m_srcOperand[0], numParts, true, dst)) {
 
                 VISA_EMask_Ctrl execMask = GetAluEMask(dst);
                 VISA_Exec_Size fromExecSize = GetAluExecSize(dst);
@@ -1756,10 +1762,10 @@ namespace IGC
         {
             unsigned numParts = 0;
             if (NeedSplitting(dst, m_encoderState.m_dstOperand, numParts) ||
-                NeedSplitting(src0, m_encoderState.m_srcOperand[0], numParts, true) ||
-                NeedSplitting(src1, m_encoderState.m_srcOperand[1], numParts, true) ||
-                NeedSplitting(src2, m_encoderState.m_srcOperand[2], numParts, true) ||
-                NeedSplitting(src3, m_encoderState.m_srcOperand[3], numParts, true)) {
+                NeedSplitting(src0, m_encoderState.m_srcOperand[0], numParts, true, dst) ||
+                NeedSplitting(src1, m_encoderState.m_srcOperand[1], numParts, true, dst) ||
+                NeedSplitting(src2, m_encoderState.m_srcOperand[2], numParts, true, dst) ||
+                NeedSplitting(src3, m_encoderState.m_srcOperand[3], numParts, true, dst)) {
 
                 VISA_EMask_Ctrl execMask = GetAluEMask(dst);
                 VISA_Exec_Size fromExecSize = GetAluExecSize(dst);
@@ -1810,9 +1816,9 @@ namespace IGC
     {
         unsigned numParts = 0;
         if (NeedSplitting(dst, m_encoderState.m_dstOperand, numParts) ||
-            NeedSplitting(src0, m_encoderState.m_srcOperand[0], numParts, true) ||
-            NeedSplitting(src1, m_encoderState.m_srcOperand[1], numParts, true) ||
-            NeedSplitting(src2, m_encoderState.m_srcOperand[2], numParts, true)) {
+            NeedSplitting(src0, m_encoderState.m_srcOperand[0], numParts, true, dst) ||
+            NeedSplitting(src1, m_encoderState.m_srcOperand[1], numParts, true, dst) ||
+            NeedSplitting(src2, m_encoderState.m_srcOperand[2], numParts, true, dst)) {
 
             VISA_EMask_Ctrl execMask = GetAluEMask(dst);
             VISA_Exec_Size fromExecSize = GetAluExecSize(dst);

IGC/Compiler/CISACodeGen/CISABuilder.hpp

@@ -450,7 +450,7 @@ namespace IGC
 
         // Variable splitting facilities (if crosses 2 GRF boundary).
         bool NeedSplitting(CVariable* var, const SModifier& mod,
-            unsigned& numParts, bool isSource = false) const;
+            unsigned& numParts, bool isSource = false, CVariable* dstVar = nullptr) const;
         SModifier SplitVariable(VISA_Exec_Size fromExecSize,
             VISA_Exec_Size toExecSize,
             unsigned thePart,