[Mlir-commits] [mlir] [mlir][vector] Fix vector.gather lowering for strided memrefs. (PR #184706)

[Andrzej Warzyński]

================
@@ -210,8 +233,23 @@ struct Gather1DToConditionalLoads : OpRewritePattern<vector::GatherOp> {
       Value condition =
           vector::ExtractOp::create(rewriter, loc, condMask, thisIdx);
       Value index = vector::ExtractOp::create(rewriter, loc, indexVec, thisIdx);
-      baseOffsets.back() =
-          rewriter.createOrFold<arith::AddIOp>(loc, lastBaseOffset, index);
+
+      if (useDelinearization) {
+        // The gather index offsets the innermost dimension. Combine with
+        // the base offsets by linearizing, adding the gather index, then
+        // delinearizing back to N-D indices:
+        //   flatIdx = linearize(baseOffsets, shape) + gatherIndex
+        //   loadIndices = delinearize(flatIdx, shape)
+        Value flatIdx =
+            rewriter.createOrFold<arith::AddIOp>(loc, linearizedBase, index);
+        auto delinOp = affine::AffineDelinearizeIndexOp::create(
+            rewriter, loc, flatIdx, basis, /*hasOuterBound=*/true);
+        for (int64_t d = 0, rank = baseOffsets.size(); d < rank; ++d)
+          baseOffsets[d] = delinOp.getResult(d);
+      } else {
+        baseOffsets.back() =
----------------
banach-space wrote:

```suggestion
        loadOffsets.back() =
```

https://github.com/llvm/llvm-project/pull/184706