[PATCH] D70897: [Matrix] Add forward shape propagation and first shape aware lowerings.

Sun Dec 8 03:27:34 PST 2019

fhahn marked an inline comment as done.
fhahn added inline comments.

================
Comment at: llvm/lib/Transforms/Scalar/LowerMatrixIntrinsics.cpp:365
+        if (OpShape != ShapeMap.end())
+          setShapeInfo(Inst, OpShape->second);
+        continue;
----------------
LuoYuanke wrote:
> It seems only store instruction is propagated with the shape information. Why? Take below pseudo code for example. Are v2 and v3 propagated with the shape information?   
> ```
> v1 = matrix_columnwise_load(..., m, n)
> v2 = max(v1, 0)
> v3 = v1 / v2
> store v3, ptr
> ```
This patch mostly adds the infrastructure for the propagation and only uses it for store instructions. So in the example, the shape is not propagated by this patch.

Additional support for loads (D70900), binary operators (D70898) and back-propagation (D70899) are added in follow-up commits, to make reviewing them more manageable. The whole patch series is linked in Phabricator (see the 'stack' section).

Please note that we could propagate shape information to more instructions, e.g. phis or selects. That can be added as follow-up as well, it is just a matter of priorities (we found loads/stores/binary operators to be by far the most common operations in matrix expressions). Any help with covering more cases would be very welcome :)

Repository:
  rG LLVM Github Monorepo

CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D70897/new/

https://reviews.llvm.org/D70897