[llvm-commits] [llvm] r59760 - in /llvm/trunk: include/llvm/CodeGen/SelectionDAGNodes.h lib/CodeGen/SelectionDAG/SelectionDAG.cpp

[Bill Wendling]

On Thu, Nov 20, 2008 at 4:22 PM, Dan Gohman <gohman at apple.com> wrote:
>
> On Nov 20, 2008, at 4:11 PM, Bill Wendling wrote:
>> +
>> +    // Overflow-aware nodes for arithmetic operations. These nodes
>> take two
>> +    // operands: the normal lhs and rhs to the add. They produce
>> two results:
>> +    // the normal result of the add, and a flag indicating whether
>> an overflow
>> +    // occured. These nodes are generated from the llvm.
>> [su]add.with.overflow
>> +    // intrinsics. They are lowered by target-dependent code.
>> +    SADDO, UADDO,
>
> Hi Bill,
>
> Is UADDO is equivalent to ADDC?
>
Hmm. It does appear to be similar. How is ADDC handled later on? I see
that the DAG combiner does some reasoning about trivial cases, but how
is it handled in the back ends?

-bw