Subzero: Initial implementation of BB Local CSE

src/IceInst.h

Index: src/IceInst.h
diff --git a/src/IceInst.h b/src/IceInst.h
index 36b8810a82bcbf0390e66283285f6cde91763239..89f308d0add56c29f1a046cfcce2db23592a8c56 100644
--- a/src/IceInst.h
+++ b/src/IceInst.h
@@ -108,6 +108,13 @@ public:
     assert(I < getSrcSize());
     return Srcs[I];
   }
+  void replaceSource(SizeT Index, Operand *Replacement) {
+    assert(Index < NumSrcs);
+    assert(!isDeleted());
+    assert(LiveRangesEnded == 0);
+    //Invalidates liveness info because the use Srcs[Index] is removed.
+    Srcs[Index] = Replacement;
+  }
 
   bool isLastUse(const Operand *Src) const;
   void spliceLivenessInfo(Inst *OrigInst, Inst *SpliceAssn);