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

[Andrzej Warzyński]

================
@@ -1103,6 +1103,127 @@ class ExtractOpFromElementwise final
   }
 };
 
+/// Pattern to rewrite vector.extract(vector.load) -> vector/memref.load.
+/// ```
+///  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, "not a load op");
+
+    if (!loadOp->hasOneUse())
+      return rewriter.notifyMatchFailure(op, "expected single op use");
+
+    VectorType memVecType = loadOp.getVectorType();
+    if (memVecType.isScalable())
+      return rewriter.notifyMatchFailure(op,
+                                         "scalable vectors are not supported");
+
+    MemRefType memType = loadOp.getMemRefType();
+    if (isa<VectorType>(memType.getElementType()))
+      return rewriter.notifyMatchFailure(
+          op, "memrefs of vectors are not supported");
+
+    int64_t rankOffset = memType.getRank() - memVecType.getRank();
+    if (rankOffset < 0)
+      return rewriter.notifyMatchFailure(op, "unsupported ranks combination");
+
+    auto resVecType = dyn_cast<VectorType>(op.getResult().getType());
+    int64_t finalRank = 0;
+    if (resVecType)
+      finalRank = resVecType.getRank();
+
+    SmallVector<Value> indices = loadOp.getIndices();
+    SmallVector<OpFoldResult> extractPos = op.getMixedPosition();
+
+    OpBuilder::InsertionGuard g(rewriter);
+    rewriter.setInsertionPoint(loadOp);
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banach-space wrote:

Typically for me, I over-iterated on the motivating example. Thanks for clarifying!

I will definitely forget this later, would you mind adding a comment?

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