[LLVMdev] Indexed Load and Store Intrinsics - proposal

[Demikhovsky, Elena]

Hi David, 


>What about the case of a gather/scatter where the BaseAddr is zero and the indices are pointers?  Must we do a ptrtoint?  llvm.org is down at the moment but I don't think we currently have a vector ptrtoint.
[Demikhovsky, Elena] From the site:
The ‘ptrtoint‘ instruction converts the pointer or a vector of pointers value to the integer (or vector of integers) type ty2.

>> Scale: a compile time constant 1, 2, 4 or 8.

>This seems a bit too Intel-focused.  Why not allow arbitrary scales?  Or alternatively, eliminate the Scale and do a vector multiply on VectorOfIndices.  It should be simple enough to write matching TableGen patterns.  We do it now for the x86 memop stuff.
[Demikhovsky, Elena] As I wrote to Nadav, may be two intrinsics will be more general. I'm just looking at usage model. If the index is a pointer, scale = 1, base = 0. If it is an index inside array, scale covers all basic types from char to double.
Do you think that 2 intrinsics will be less-Intel-focused?
(1) non-zero base and vector of indices (index is relative to base) and implicit scale based on element type.
(2) without base, without scale, just vector of pointers

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