[PowerPC] Add support for intrinsics dcbfps and dcbstps in P10.

[Esme]

Summary

This patch added support for the intrinsics llvm.ppc.dcbfps and llvm.ppc.dcbstps.
dcbfps and dcbstps are actually extended mnemonics of dcbf.

dcbfps RA,RB ---> dcbf RA,RB,4
dcbstps RA,RB ---> dcbf RA,RB,6

[amyk]

This LGTM.

llvm/test/CodeGen/PowerPC/dcbf-p10.ll

3

I think it would be good to add a BE line when testing new intrinsics.

[Esme]

Added a BE line in the test.

[steven.zhang]

llvm/include/llvm/IR/IntrinsicsPowerPC.td

40

I didn't go into the detail of the definition of the intrinsic. But could you please double confirm if we need to set IntrWriteMem, IntrArgMemOnly as it seems that dbcf stuff is trying to write memory.

[Esme]

llvm/include/llvm/IR/IntrinsicsPowerPC.td

40

Thanks for your comment. The dcbf_ instructions perform the writes to main storage instead of memory. So there is no need to set IntrWriteMem, IntrArgMemOnly. Please correct me if I am wrong.

[Esme]

According to ISA,

DCBF (Data Cache Block Flush) is treated as a Load, except that reference and change recording need not be done.

it is appropriate to set IntrReadMem, IntrArgMemOnly for these dcbf_ instructions.

[steven.zhang]

LGTM now.

[Esme]

@steven.zhang I still have some doubts about the properties setting. According to the behavior described by ISA, it also includes the write operation?

...those locations are written to main storage and additional locations in the block may be written to main storage...

I think it would be a safer way to only set IntrArgMemOnly.