[PATCH] D29268: [DAGCombine] Combine composition of ADDC(ADDE)
Amaury SECHET via Phabricator via llvm-commits
llvm-commits at lists.llvm.org
Mon Jan 30 00:43:22 PST 2017
deadalnix added inline comments.
Comment at: lib/CodeGen/SelectionDAG/DAGCombiner.cpp:1872
+ if (N1.getOpcode() == ISD::ADDE &&
+ N->isOnlyUserOf(N1.getValue(0).getNode()) &&
Is that important to check this has only one use ? I'd assume that having (adde Y, 0, Carry) + (adde X, Y, Carry) is still preferable to (addc X, (adde Y, 0, Carry)) as it break dependencies between instructions.
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