Check in LVN pass if the use instruction supports source modifiers

Change-Id: I75212fdc961fe696643ee24f224115eefb66c7ce

Author: weiyu-chen

visa/Gen4_IR.cpp

@@ -7423,6 +7423,11 @@ bool G4_INST::canSupportCondMod() const
         (op == G4_xor));
 }
 
+bool G4_INST::canSupportSrcModifier() const
+{
+    return !isSend();
+}
+
 // convert (execsize, offset) into emask option
 // if no such mask option exists, return InstOpt_NoOpt
 G4_InstOption G4_INST::offsetToMask(int execSize, int offset, bool nibOk)

visa/Gen4_IR.hpp

@@ -1119,6 +1119,7 @@ class G4_INST
     bool canSupportCondMod() const;
     bool canSwapSource() const;
     bool canSupportSaturate() const;
+    bool canSupportSrcModifier() const;
 
     bool usesFlag() const
     {

visa/LVN.cpp

@@ -290,11 +290,9 @@ bool LVN::canReplaceUses(INST_LIST_ITER inst_it, UseList& uses, G4_INST* lvnInst
 
         if (negMatch)
         {
-            if (useInst->isSend())
+            if (!useInst->canSupportSrcModifier())
             {
-                // send src opnd doesnt support negate modifier.
-                // So if LVN found a pattern that requires the
-                // modifier then this optimization is invalid.
+                // LVN is invalid if instruction does not support negatve modifier
                 canReplace = false;
                 break;
             }