[PATCH] D41791: [DAG Legalization] Zero-extend the value compared in cmpxchg

[Eli Friedman via Phabricator via llvm-commits]

efriedma added inline comments.


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Comment at: lib/CodeGen/SelectionDAG/LegalizeIntegerTypes.cpp:236
 
-  SDValue Op2 = GetPromotedInteger(N->getOperand(2));
+  SDValue Op2 = ZExtPromotedInteger(N->getOperand(2));
   SDValue Op3 = GetPromotedInteger(N->getOperand(3));
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The value operand to a store is implicitly truncated.  The same thing happens for ATOMIC_LOAD_*.  The same thing happens for the third operand of ATOMIC_CMP_SWAP.  I think it's more confusing than helpful to add a special case for the compare operand of a compare.  Atomic compare-and-swap doesn't zero-extend on all targets, anyway; see getExtendForAtomicOps().


Repository:
  rL LLVM

https://reviews.llvm.org/D41791