[Mlir-commits] [mlir] [mlir][Tensor] Add rank-reducing slice in generatedSlices (PR #174248)

[Bangtian Liu]

https://github.com/bangtianliu updated https://github.com/llvm/llvm-project/pull/174248

>From 776f4cfd2b489a92785dd749542425455ffaea5b Mon Sep 17 00:00:00 2001
From: Bangtian Liu <liubangtian at gmail.com>
Date: Fri, 2 Jan 2026 14:54:43 -0800
Subject: [PATCH 1/2] [mlir][Tensor] Add rank-reducing slice in generatedSlices

Signed-off-by: Bangtian Liu <liubangtian at gmail.com>
---
 .../Tensor/Transforms/SwapExtractSliceWithProducerPatterns.cpp   | 1 +
 1 file changed, 1 insertion(+)

diff --git a/mlir/lib/Dialect/Tensor/Transforms/SwapExtractSliceWithProducerPatterns.cpp b/mlir/lib/Dialect/Tensor/Transforms/SwapExtractSliceWithProducerPatterns.cpp
index 549ac7afca8ca..7903f3c51b73b 100644
--- a/mlir/lib/Dialect/Tensor/Transforms/SwapExtractSliceWithProducerPatterns.cpp
+++ b/mlir/lib/Dialect/Tensor/Transforms/SwapExtractSliceWithProducerPatterns.cpp
@@ -53,6 +53,7 @@ FailureOr<TilingResult> tensor::replaceExtractSliceWithTiledProducer(
         builder, sliceOp.getLoc(), sliceOp.getType(),
         tiledResult->tiledValues[0], offsets, sliceOp.getMixedSizes(), strides);
     tiledResult->tiledValues[0] = newSliceOp;
+    tiledResult->generatedSlices.push_back(newSliceOp);
   }
 
   return *tiledResult;

>From b0699cc109d137e43ca0c71ffe48c9aad531f70f Mon Sep 17 00:00:00 2001
From: Bangtian Liu <liubangtian at gmail.com>
Date: Fri, 2 Jan 2026 17:27:51 -0800
Subject: [PATCH 2/2] fix timeout issue

Signed-off-by: Bangtian Liu <liubangtian at gmail.com>
---
 .../Dialect/SCF/Transforms/TileUsingInterface.cpp  | 14 +++++++++++++-
 1 file changed, 13 insertions(+), 1 deletion(-)

diff --git a/mlir/lib/Dialect/SCF/Transforms/TileUsingInterface.cpp b/mlir/lib/Dialect/SCF/Transforms/TileUsingInterface.cpp
index 009c2c3537411..877d1d2bd975e 100644
--- a/mlir/lib/Dialect/SCF/Transforms/TileUsingInterface.cpp
+++ b/mlir/lib/Dialect/SCF/Transforms/TileUsingInterface.cpp
@@ -1316,6 +1316,7 @@ getUntiledProducerFromSliceSource(OpOperand *source,
                                   ArrayRef<LoopLikeOpInterface> loops) {
   std::optional<OpOperand *> destinationIterArg;
   assert(!loops.empty() && "expected non empty loops container");
+
   auto loopIt = loops.rbegin();
   while (loopIt != loops.rend() && isa<BlockArgument>(source->get())) {
     auto iterArg = cast<BlockArgument>(source->get());
@@ -1327,7 +1328,18 @@ getUntiledProducerFromSliceSource(OpOperand *source,
   }
   if (loopIt == loops.rend())
     destinationIterArg = source;
-  return {dyn_cast<OpResult>(source->get()), destinationIterArg};
+
+  OpResult result = dyn_cast<OpResult>(source->get());
+  if (result) {
+    Operation *producer = result.getOwner();
+    Operation *innermostLoop = loops.back();
+    // If the producer is already inside the innermost loop (where the slice
+    // is), it has already been fused. Skip it to avoid infinite loops.
+    if (innermostLoop->isProperAncestor(producer))
+      return {OpResult(), std::nullopt};
+  }
+
+  return {result, destinationIterArg};
 }
 
 /// Implementation of fusing producer of a single slice by computing the