[Mlir-commits] [mlir] [mlir][vector] Sink vector.extract/splat into load/store ops (PR #134389)

[Andrzej Warzyński]

================
@@ -1043,6 +1047,144 @@ class ExtractOpFromElementwise final
   }
 };
 
+static bool isSupportedMemSinkElementType(Type type) {
+  if (isa<IndexType>(type))
+    return true;
+
+  // Non-byte-aligned types are tricky, skip them.
+  return type.isIntOrFloat() && type.getIntOrFloatBitWidth() % 8 == 0;
+}
+
+/// Pattern to rewrite vector.extract(vector.load) -> vector/memref.load.
+///
+/// Example:
+/// ```
+///  vector.load %arg0[%arg1] : memref<?xf32>, vector<4xf32>
+///  vector.extract %0[1] : f32 from vector<4xf32>
+/// ```
+/// Gets converted to:
+/// ```
+/// %c1 = arith.constant 1 : index
+/// %0 = arith.addi %arg1, %c1 overflow<nsw> : index
+/// %1 = memref.load %arg0[%0] : memref<?xf32>
+/// ```
+class ExtractOpFromLoad final : public OpRewritePattern<vector::ExtractOp> {
+public:
+  using OpRewritePattern::OpRewritePattern;
+
+  LogicalResult matchAndRewrite(vector::ExtractOp op,
+                                PatternRewriter &rewriter) const override {
+    auto loadOp = op.getVector().getDefiningOp<vector::LoadOp>();
+    if (!loadOp)
+      return rewriter.notifyMatchFailure(op, "expected a load op");
+
+    // Checking for single use so we won't duplicate load ops.
+    if (!loadOp->hasOneUse())
+      return rewriter.notifyMatchFailure(op, "expected single op use");
+
+    VectorType loadVecType = loadOp.getVectorType();
+    if (loadVecType.isScalable())
+      return rewriter.notifyMatchFailure(op,
+                                         "scalable vectors are not supported");
+
+    MemRefType memType = loadOp.getMemRefType();
+    if (!isSupportedMemSinkElementType(memType.getElementType()))
+      return rewriter.notifyMatchFailure(op, "unsupported memref element type");
----------------
banach-space wrote:

[nit] The element type is not really specific to the memref, right?
```suggestion
      return rewriter.notifyMatchFailure(op, "unsupported element type");
```

https://github.com/llvm/llvm-project/pull/134389