[Mlir-commits] [mlir] [mlir][memref-to-spirv]: Reverse Image Load Coordinates (PR #160495)

[Jakub Kuderski]

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@@ -699,6 +699,36 @@ LoadOpPattern::matchAndRewrite(memref::LoadOp loadOp, OpAdaptor adaptor,
   return success();
 }
 
+template <typename OpAdaptor>
+static FailureOr<SmallVector<Value>>
+extractLoadCoordsForComposite(memref::LoadOp loadOp, OpAdaptor adaptor,
+                              ConversionPatternRewriter &rewriter) {
+  // At present we only support linear "tiling" as specified in Vulkan, this
+  // means that texels are assumed to be laid out in memory in a row-major
+  // order. This allows us to support any memref layout that is a permutation of
+  // the dimensions. Future work will pass an optional image layout to the
+  // rewrite pattern so that we can support optimized target specific tilings.
+  //
+  // The memrefs layout determines the dimension ordering so we need to invert
+  // the map to get the ordering.
+  SmallVector<Value> indices = adaptor.getIndices();
+  auto map = loadOp.getMemRefType().getLayout().getAffineMap();
+  if (!map.isPermutation())
+    return rewriter.notifyMatchFailure(
+        loadOp,
+        "Cannot lower memrefs with memory layout which is not a permutation");
+
+  const unsigned dimCount = map.getNumDims();
+  SmallVector<Value, 3> coords(dimCount);
+  for (unsigned dim = 0; dim < dimCount; ++dim)
+    coords[map.getDimPosition(dim)] = indices[dim];
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kuhar wrote:

Maybe it would be worth adding as a code comment too?

https://github.com/llvm/llvm-project/pull/160495