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..97b7f747264d7d4bf53791f919e930eec1cb312c 100644
--- a/src/IceInst.h
+++ b/src/IceInst.h
@@ -108,6 +108,10 @@ public:
     assert(I < getSrcSize());
     return Srcs[I];
   }
+  void replaceSource(SizeT Index, Operand *Replacement) {
+    assert(Index < NumSrcs);

[Jim Stichnoth, 2016/05/19 01:35:50]

For safety, add a couple more asserts:
  assert(!isDeleted());
  assert(LiveRangesEnded == 0);

The latter one mostly ensures you don't call the method at a point where it
might be "dangerous" because you're relying on previously computed liveness info
that might now become out of sync.

+    Srcs[Index] = Replacement;
+  }
 
   bool isLastUse(const Operand *Src) const;
   void spliceLivenessInfo(Inst *OrigInst, Inst *SpliceAssn);