[llvm-dev] REG_SEQUENCE use question

[Krzysztof Parzyszek via llvm-dev]

On 3/22/2017 3:15 PM, Peter Bel via llvm-dev wrote:
> Yes, that will hold for the reg copy. But what about copying an
> immediate? Or subdividing one wide reg into two standard to run some math?

You can have a Pat that will convert an immediate into a value in a 
register. For example (from HexagonPatterns.td):

def: Pat<(s32_0ImmPred:$s16), (A2_tfrsi imm:$s16)>;

For dividing regs we use PatFrags LoReg and HiReg.

-Krzysztof

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