[Mlir-commits] [mlir] [mlir][x86vector] Wrapping `populateFlattenVectorTransferPatterns` as a transform pass. (PR #178134)

Arun Thangamani llvmlistbot at llvm.org
Tue Jan 27 07:22:28 PST 2026


https://github.com/arun-thmn updated https://github.com/llvm/llvm-project/pull/178134

>From a782e6fd890175a999f04e0f135403535c8fe26c Mon Sep 17 00:00:00 2001
From: Arun Thangamani <arun.thangamani at intel.com>
Date: Mon, 26 Jan 2026 23:58:24 -0800
Subject: [PATCH 1/4] Wrapping populateFlattenVectorTransferPatterns as a
 transform pass

---
 .../X86Vector/TransformOps/X86VectorTransformOps.td   | 11 +++++++++++
 mlir/include/mlir/Dialect/X86Vector/Transforms.h      |  5 +++++
 .../X86Vector/TransformOps/X86VectorTransformOps.cpp  |  7 +++++++
 3 files changed, 23 insertions(+)

diff --git a/mlir/include/mlir/Dialect/X86Vector/TransformOps/X86VectorTransformOps.td b/mlir/include/mlir/Dialect/X86Vector/TransformOps/X86VectorTransformOps.td
index 891829fca017f..4c953abc125bc 100644
--- a/mlir/include/mlir/Dialect/X86Vector/TransformOps/X86VectorTransformOps.td
+++ b/mlir/include/mlir/Dialect/X86Vector/TransformOps/X86VectorTransformOps.td
@@ -71,6 +71,17 @@ def ApplyShuffleVectorFMAOpsPatternsOp : Op<Transform_Dialect,
   let assemblyFormat = "attr-dict";
 }
 
+def ApplyFlattenVectorTransferOpsPatternsOp : Op<Transform_Dialect,
+    "apply_patterns.x86vector.flatten_vector_transfer_ops",
+    [DeclareOpInterfaceMethods<PatternDescriptorOpInterface>]> {
+  let description = [{
+    Collect patterns to rewrite contiguous row-major vector.transfer_read or 
+    vector.transfer_write operations to a 1D operation.
+  }];
+
+  let assemblyFormat = "attr-dict";
+}
+
 
 #endif // X86VECTOR_TRANSFORM_OPS
 
diff --git a/mlir/include/mlir/Dialect/X86Vector/Transforms.h b/mlir/include/mlir/Dialect/X86Vector/Transforms.h
index aadca92708908..3c73a2e172487 100644
--- a/mlir/include/mlir/Dialect/X86Vector/Transforms.h
+++ b/mlir/include/mlir/Dialect/X86Vector/Transforms.h
@@ -104,6 +104,11 @@ void populateSinkVectorProducerOpsPatterns(RewritePatternSet &patterns);
 // grouped with respect to odd/even packed index.
 void populateShuffleVectorFMAOpsPatterns(RewritePatternSet &patterns);
 
+// Rewrites contiguous row-major vector.transfer_read or vector.transfer_write
+// operations by inserting  a memref.collapse_shape on the source,
+// transforming the operation to use a 1D source.
+void populateFlattenVectorTransferOpsPatterns(RewritePatternSet &patterns);
+
 //===----------------------------------------------------------------------===//
 /// Helpers extracted from:
 ///   - clang/lib/Headers/avxintrin.h
diff --git a/mlir/lib/Dialect/X86Vector/TransformOps/X86VectorTransformOps.cpp b/mlir/lib/Dialect/X86Vector/TransformOps/X86VectorTransformOps.cpp
index c6be69305da50..57b0cfc162b8d 100644
--- a/mlir/lib/Dialect/X86Vector/TransformOps/X86VectorTransformOps.cpp
+++ b/mlir/lib/Dialect/X86Vector/TransformOps/X86VectorTransformOps.cpp
@@ -12,6 +12,7 @@
 #include "mlir/Dialect/Transform/IR/TransformDialect.h"
 #include "mlir/Dialect/Transform/Interfaces/TransformInterfaces.h"
 #include "mlir/Dialect/Vector/IR/VectorOps.h"
+#include "mlir/Dialect/Vector/Transforms/VectorRewritePatterns.h"
 #include "mlir/Dialect/X86Vector/Transforms.h"
 #include "mlir/Dialect/X86Vector/X86VectorDialect.h"
 
@@ -21,6 +22,7 @@
 using namespace mlir;
 using namespace mlir::x86vector;
 using namespace mlir::transform;
+using namespace mlir::vector;
 
 void mlir::transform::ApplyVectorContractToFMAPatternsOp::populatePatterns(
     RewritePatternSet &patterns) {
@@ -47,6 +49,11 @@ void mlir::transform::ApplyShuffleVectorFMAOpsPatternsOp::populatePatterns(
   x86vector::populateShuffleVectorFMAOpsPatterns(patterns);
 }
 
+void mlir::transform::ApplyFlattenVectorTransferOpsPatternsOp::
+    populatePatterns(RewritePatternSet &patterns) {
+  vector::populateFlattenVectorTransferPatterns(patterns);
+}
+
 //===----------------------------------------------------------------------===//
 // Transform op registration
 //===----------------------------------------------------------------------===//

>From 1887de8f1f9e8dc33654ae545e0e309ea385a09a Mon Sep 17 00:00:00 2001
From: Arun Thangamani <arun.thangamani at intel.com>
Date: Tue, 27 Jan 2026 00:07:31 -0800
Subject: [PATCH 2/4] fixing a clang-format error

---
 .../Dialect/X86Vector/TransformOps/X86VectorTransformOps.cpp  | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/mlir/lib/Dialect/X86Vector/TransformOps/X86VectorTransformOps.cpp b/mlir/lib/Dialect/X86Vector/TransformOps/X86VectorTransformOps.cpp
index 57b0cfc162b8d..cfc6c4194f5af 100644
--- a/mlir/lib/Dialect/X86Vector/TransformOps/X86VectorTransformOps.cpp
+++ b/mlir/lib/Dialect/X86Vector/TransformOps/X86VectorTransformOps.cpp
@@ -49,8 +49,8 @@ void mlir::transform::ApplyShuffleVectorFMAOpsPatternsOp::populatePatterns(
   x86vector::populateShuffleVectorFMAOpsPatterns(patterns);
 }
 
-void mlir::transform::ApplyFlattenVectorTransferOpsPatternsOp::
-    populatePatterns(RewritePatternSet &patterns) {
+void mlir::transform::ApplyFlattenVectorTransferOpsPatternsOp::populatePatterns(
+    RewritePatternSet &patterns) {
   vector::populateFlattenVectorTransferPatterns(patterns);
 }
 

>From 32eeea8f5f1d5858ff0149dc0270c6fdf7e1b7e8 Mon Sep 17 00:00:00 2001
From: Arun Thangamani <arun.thangamani at intel.com>
Date: Tue, 27 Jan 2026 07:20:54 -0800
Subject: [PATCH 3/4] added an argument + one test-case for validation

---
 .../X86Vector/TransformOps/X86VectorTransformOps.td    | 10 ++++++++--
 mlir/include/mlir/Dialect/X86Vector/Transforms.h       |  4 +++-
 .../X86Vector/TransformOps/X86VectorTransformOps.cpp   |  3 ++-
 3 files changed, 13 insertions(+), 4 deletions(-)

diff --git a/mlir/include/mlir/Dialect/X86Vector/TransformOps/X86VectorTransformOps.td b/mlir/include/mlir/Dialect/X86Vector/TransformOps/X86VectorTransformOps.td
index 4c953abc125bc..f41caa87f7375 100644
--- a/mlir/include/mlir/Dialect/X86Vector/TransformOps/X86VectorTransformOps.td
+++ b/mlir/include/mlir/Dialect/X86Vector/TransformOps/X86VectorTransformOps.td
@@ -79,9 +79,15 @@ def ApplyFlattenVectorTransferOpsPatternsOp : Op<Transform_Dialect,
     vector.transfer_write operations to a 1D operation.
   }];
 
-  let assemblyFormat = "attr-dict";
-}
+  let arguments = (ins
+  DefaultValuedAttr<UI32Attr,
+    "std::numeric_limits<unsigned>::max()">:$target_vector_bitwidth
+  );
 
+  let assemblyFormat = [{
+    (`target_vector_bitwidth` `=` $target_vector_bitwidth^)? attr-dict
+  }];
+}
 
 #endif // X86VECTOR_TRANSFORM_OPS
 
diff --git a/mlir/include/mlir/Dialect/X86Vector/Transforms.h b/mlir/include/mlir/Dialect/X86Vector/Transforms.h
index 3c73a2e172487..f2a1d58f42c1f 100644
--- a/mlir/include/mlir/Dialect/X86Vector/Transforms.h
+++ b/mlir/include/mlir/Dialect/X86Vector/Transforms.h
@@ -107,7 +107,9 @@ void populateShuffleVectorFMAOpsPatterns(RewritePatternSet &patterns);
 // Rewrites contiguous row-major vector.transfer_read or vector.transfer_write
 // operations by inserting  a memref.collapse_shape on the source,
 // transforming the operation to use a 1D source.
-void populateFlattenVectorTransferOpsPatterns(RewritePatternSet &patterns);
+void populateFlattenVectorTransferOpsPatterns(
+    RewritePatternSet &patterns,
+    unsigned targetVectorBitwidth = std::numeric_limits<unsigned>::max());
 
 //===----------------------------------------------------------------------===//
 /// Helpers extracted from:
diff --git a/mlir/lib/Dialect/X86Vector/TransformOps/X86VectorTransformOps.cpp b/mlir/lib/Dialect/X86Vector/TransformOps/X86VectorTransformOps.cpp
index cfc6c4194f5af..7601966a4652c 100644
--- a/mlir/lib/Dialect/X86Vector/TransformOps/X86VectorTransformOps.cpp
+++ b/mlir/lib/Dialect/X86Vector/TransformOps/X86VectorTransformOps.cpp
@@ -51,7 +51,8 @@ void mlir::transform::ApplyShuffleVectorFMAOpsPatternsOp::populatePatterns(
 
 void mlir::transform::ApplyFlattenVectorTransferOpsPatternsOp::populatePatterns(
     RewritePatternSet &patterns) {
-  vector::populateFlattenVectorTransferPatterns(patterns);
+  vector::populateFlattenVectorTransferPatterns(patterns,
+                                                getTargetVectorBitwidth());
 }
 
 //===----------------------------------------------------------------------===//

>From ad9384d161233bec3cf9e977d2ce68913ff0be62 Mon Sep 17 00:00:00 2001
From: Arun Thangamani <arun.thangamani at intel.com>
Date: Tue, 27 Jan 2026 07:21:58 -0800
Subject: [PATCH 4/4] added an argument + one test-case for validation

---
 .../flatten-vector-transfer-ops.mlir          | 31 +++++++++++++++++++
 1 file changed, 31 insertions(+)
 create mode 100644 mlir/test/Dialect/X86Vector/flatten-vector-transfer-ops.mlir

diff --git a/mlir/test/Dialect/X86Vector/flatten-vector-transfer-ops.mlir b/mlir/test/Dialect/X86Vector/flatten-vector-transfer-ops.mlir
new file mode 100644
index 0000000000000..40c39c5f51c2a
--- /dev/null
+++ b/mlir/test/Dialect/X86Vector/flatten-vector-transfer-ops.mlir
@@ -0,0 +1,31 @@
+// RUN: mlir-opt %s -transform-interpreter -cse -split-input-file | FileCheck %s
+
+func.func @flatten_transfer_ops(%arg0: memref<16x16xf32>, %arg1: vector<8xf32>) -> vector<8xf32> {
+  %c0 = arith.constant 0 : index
+  %c8 = arith.constant 8 : index
+  %b0 = ub.poison : f32
+  %0 = vector.transfer_read %arg0[%c0, %c0], %b0 {in_bounds = [true, true]} : memref<16x16xf32>, vector<1x8xf32>
+  %1 = vector.transfer_read %arg0[%c0, %c8], %b0 {in_bounds = [true, true]} : memref<16x16xf32>, vector<1x8xf32>
+  %2 = vector.shape_cast %0 : vector<1x8xf32> to vector<8xf32>
+  %3 = vector.shape_cast %1 : vector<1x8xf32> to vector<8xf32>
+  %4 = vector.fma %2, %3, %arg1 : vector<8xf32>
+  return %4 : vector<8xf32>
+}
+
+// CHECK-LABEL: @flatten_transfer_ops
+// CHECK-NOT: vector.transfer_read {{.*}},  vector<1x8xf32>
+// CHECK-NOT: vector.transfer_read {{.*}},  vector<1x8xf32>
+// CHECK: vector.transfer_read {{.*}},  vector<8xf32> 
+// CHECK-NEXT: vector.transfer_read {{.*}},  vector<8xf32>
+// CHECK-NOT: vector.shape_cast
+// CHECK-NOT: vector.shape_cast
+
+module attributes {transform.with_named_sequence} {
+  transform.named_sequence @__transform_main(%arg1: !transform.any_op {transform.readonly}) {
+    %func = transform.structured.match ops{["func.func"]} in %arg1 : (!transform.any_op) -> !transform.any_op
+    transform.apply_patterns to %func {
+      transform.apply_patterns.x86vector.flatten_vector_transfer_ops
+    } : !transform.any_op
+    transform.yield
+  }
+}



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