Enable float accumualator for sel, second try.

Author: weiyu-chen

visa/AccSubstitution.cpp

@@ -441,10 +441,11 @@ bool AccSubPass::isAccCandidate(G4_INST* inst, int& lastUse, bool& mustBeAcc0, i
         return false;
     }
 
-    if (inst->getCondMod())
+    if (inst->getCondMod() && inst->opcode() != G4_sel)
     {
         // since our du-chain is on inst instead of operand, the presence of conditional modifier complicates the checks later.
         // This is somewhat conservative but shouldn't matter too much as inst with both dst and conditional modifiers are rare.
+        // Exception is for sel as flag register is not updated.
         return false;
     }
 

visa/Gen4_IR.cpp

@@ -7980,13 +7980,15 @@ bool G4_INST::canDstBeAcc() const
     case G4_rnde:
     case G4_rndu:
     case G4_rndz:
-    case G4_sel:
     case G4_shr:
     case G4_smov:
     case G4_xor:
     case G4_rol:
     case G4_ror:
         return true;
+    case G4_sel:
+        // sel seems to fail with int acc for some strange reason (sign extension?)
+        return getCondMod() ? IS_TYPE_FLOAT_ALL(dst->getType()) : true;
     case G4_cmp:
     case G4_cmpn:
         // disable for now since it's causing some SKL tests to fail