Combine DMA loads about vc4c HOT 6 OPEN

In general, you can query Local#getUsers(LocalUse::Type::WRITER) to get all writers.

If there is just one writer, Local#getSingleWriter() will do the trick. Also if you have a Value instead of the local, you can call Value#getSingleWriter() which does the same, but checks whether the value is a local. Of course the result needs to be checked for nullptr in both cases!

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There is already some related code there. This was added some while ago to do a similar job, but I am not sure whether it is still applied. Anyway, that might be a good point to start.

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@doe300 I have a question. Is there a way to find the instruction corresponded the local (for example, I want to get the instruction %sub1 = sub i32 %mul, %width from the value i32 %sub1). Or should I create this method?

%mul = mul nsw i32 %y.024, %width
%sub1 = sub i32 %mul, %width
%add = add i32 %mul, %width

%call = tail call spir_func <16 x i8> @_Z7vload16jPU3AS1Kh(i32 %sub1, i8 addrspace(1)* %in) #2
%call2 = tail call spir_func <16 x i8> @_Z7vload16jPU3AS1Kh(i32 %mul, i8 addrspace(1)* %in) #2
%call3 = tail call spir_func <16 x i8> @_Z7vload16jPU3AS1Kh(i32 %add, i8 addrspace(1)* %in) #2

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@doe300 I want to insert the instruction (extends IntermediateInstruction) which do VPM load here, but I cannot find it.
Is there such the instruction, or should I create the instruction?

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The general memory access (before we know whether the memory area is lowered to a register, the VPM or accessed via TMU or DMA) is represented as MemoryInstruction.
After the lowering, there are no specific instruction types for the various lowered types (e.g. register, VPM), instead the MemoryInstruction is directly composed to the (hardware) instructions executed to do the memory accesses.
So if you want to insert a VPM access, have a look at the VPM header:

• insertReadDMA, insertWriteDMA for "direct" DMA access (QPU <-> RAM), abstracting away the VPM
• VPM::insertReadVPM, VPM::insertWriteVPM for VPM access (QPU <-> VPM), e.g. also for caching/exchanging data between QPUs
• VPM::insertReadRAM, VPM::insertWriteRAM for DMA only access (VPM <-> RAM), e.g. to read/write back cached data

The VPM object required can be retrieved via the Method::vpm member.

Does this information suffice or do you need a special instruction type to represent VPM accesses (e.g. for further processing)?

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I understand, thanks.

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