[LLVMdev] Support for PPC 440/450

Jakob Stoklund Olesen stoklund at 2pi.dk
Wed Oct 5 14:14:50 PDT 2011

On Oct 5, 2011, at 8:22 AM, Hal Finkel wrote:

> I've been working on adding support for the PPC 440/450 "embedded" cores
> to the PowerPC backend. These are used on IBM's Blue Gene L and P
> supercomputers, but are also used in other environments (like on the
> Xilinx Virtex-5). Here is my first patch. I'm new to LLVM, and so I
> apologize if this is the wrong way to do this [the online docs seem to
> imply that a patch should be sent to a mailing list, although does not
> specify which one, should it go to the bug tracker instead?].

llvm-commits is the place to send your patches.

> I've tried to touch as little of the existing code as possible. There
> are some other changes which should probably be made, but would require
> touching the existing PowerPC code.

This patch looks fine to me, but I am missing some test cases.

There should at least be a test case just sending some code through this scheduler.

> For example, the general load/store
> itinerary should really be split into a general load and general store.
> Also, on the so-called "Book E" embedded PPC cores, the sync instruction
> is called msync (same opcode, different name). I'm not sure what the
> best way of doing a predicate-base asm name is.

I am not sure how to do that.  X86 has alternative syntaxes, but that is way overkill.

> I'm just about done with a patch to add support for the FP2 (aka Double
> Hummer) v2f64 vector instruction set, but I figured that it would be
> good to make that a separate patch.



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