[llvm-branch-commits] [mlir] [mlir][VectorToLLVM] Use the converted index type in vector.type_cast (PR #218742)

[Christian Ulmann via llvm-branch-commits]

https://github.com/Dinistro updated https://github.com/llvm/llvm-project/pull/218742

>From 9e1b5516eb0406a15bd68ab96d74e07f61a69c74 Mon Sep 17 00:00:00 2001
From: Christian Ulmann <christian.ulmann at nextsilicon.com>
Date: Tue, 25 Aug 2026 16:36:12 +0200
Subject: [PATCH 1/2] [mlir][VectorToLLVM] Use the converted index type in
 vector.type_cast

`VectorTypeCastOpConversion` hardcoded `i64` for the offset, size and stride
constants it inserts into the target memref descriptor, while the descriptor's
fields have the converted index type. With a type converter configured for a
32-bit index the pattern therefore emitted invalid IR:

  'llvm.insertvalue' op Type mismatch: cannot insert 'i64' into
  '!llvm.struct<(ptr, ptr, i32)>'

Build the constants from the converted index type instead.

Co-Authored-By: Claude Opus 5 (1M context) <noreply at anthropic.com>
---
 .../VectorToLLVM/ConvertVectorToLLVM.cpp      | 24 +++++++++----------
 .../VectorToLLVM/vector-to-llvm-32b.mlir      | 16 +++++++++++++
 2 files changed, 27 insertions(+), 13 deletions(-)
 create mode 100644 mlir/test/Conversion/VectorToLLVM/vector-to-llvm-32b.mlir

diff --git a/mlir/lib/Conversion/VectorToLLVM/ConvertVectorToLLVM.cpp b/mlir/lib/Conversion/VectorToLLVM/ConvertVectorToLLVM.cpp
index 54c117bae476b..98d701147e3dc 100644
--- a/mlir/lib/Conversion/VectorToLLVM/ConvertVectorToLLVM.cpp
+++ b/mlir/lib/Conversion/VectorToLLVM/ConvertVectorToLLVM.cpp
@@ -1479,7 +1479,9 @@ class VectorTypeCastOpConversion
     if (llvm::any_of(*targetStrides, ShapedType::isDynamic))
       return failure();
 
-    auto int64Ty = IntegerType::get(rewriter.getContext(), 64);
+    // The offset, size and stride fields of a memref descriptor use the
+    // converted index type.
+    Type indexTy = getTypeConverter()->getIndexType();
 
     // Create descriptor.
     auto desc = MemRefDescriptor::poison(rewriter, loc, llvmTargetDescriptorTy);
@@ -1491,23 +1493,19 @@ class VectorTypeCastOpConversion
     Value ptr = sourceMemRef.alignedPtr(rewriter, loc);
     desc.setAlignedPtr(rewriter, loc, ptr);
     // Fill offset 0.
-    auto attr = rewriter.getIntegerAttr(rewriter.getIndexType(), 0);
-    auto zero = LLVM::ConstantOp::create(rewriter, loc, int64Ty, attr);
-    desc.setOffset(rewriter, loc, zero);
+    desc.setOffset(rewriter, loc,
+                   LLVM::createIndexAttrConstant(rewriter, loc, indexTy, 0));
 
     // Fill size and stride descriptors in memref.
     for (const auto &indexedSize :
          llvm::enumerate(targetMemRefType.getShape())) {
       int64_t index = indexedSize.index();
-      auto sizeAttr =
-          rewriter.getIntegerAttr(rewriter.getIndexType(), indexedSize.value());
-      auto size = LLVM::ConstantOp::create(rewriter, loc, int64Ty, sizeAttr);
-      desc.setSize(rewriter, loc, index, size);
-      auto strideAttr = rewriter.getIntegerAttr(rewriter.getIndexType(),
-                                                (*targetStrides)[index]);
-      auto stride =
-          LLVM::ConstantOp::create(rewriter, loc, int64Ty, strideAttr);
-      desc.setStride(rewriter, loc, index, stride);
+      desc.setSize(rewriter, loc, index,
+                   LLVM::createIndexAttrConstant(rewriter, loc, indexTy,
+                                                 indexedSize.value()));
+      desc.setStride(rewriter, loc, index,
+                     LLVM::createIndexAttrConstant(rewriter, loc, indexTy,
+                                                   (*targetStrides)[index]));
     }
 
     rewriter.replaceOp(castOp, {desc});
diff --git a/mlir/test/Conversion/VectorToLLVM/vector-to-llvm-32b.mlir b/mlir/test/Conversion/VectorToLLVM/vector-to-llvm-32b.mlir
new file mode 100644
index 0000000000000..5a816eed8ab36
--- /dev/null
+++ b/mlir/test/Conversion/VectorToLLVM/vector-to-llvm-32b.mlir
@@ -0,0 +1,16 @@
+// The memref descriptor fields use the converted index type, which is not
+// necessarily `i64`.
+
+// RUN: mlir-opt %s --convert-to-llvm | FileCheck %s
+
+module attributes {dlti.dl_spec = #dlti.dl_spec<
+  #dlti.dl_entry<index, 32>,
+>} {
+  // CHECK-LABEL: llvm.func @type_cast
+  //       CHECK:   %[[OFFSET:.*]] = llvm.mlir.constant(0 : index) : i32
+  //       CHECK:   llvm.insertvalue %[[OFFSET]], %{{.*}}[2] : !llvm.struct<(ptr, ptr, i32)>
+  func.func @type_cast(%arg0: memref<8x8x8xf32>) -> memref<vector<8x8x8xf32>> {
+    %0 = vector.type_cast %arg0 : memref<8x8x8xf32> to memref<vector<8x8x8xf32>>
+    return %0 : memref<vector<8x8x8xf32>>
+  }
+}

>From 82d338d8873cf0e1141087dfbf1b4258143305b0 Mon Sep 17 00:00:00 2001
From: Christian Ulmann <christian.ulmann at nextsilicon.com>
Date: Wed, 26 Aug 2026 07:34:01 +0200
Subject: [PATCH 2/2] test fix

---
 mlir/test/Conversion/VectorToLLVM/vector-to-llvm-32b.mlir | 7 ++++---
 1 file changed, 4 insertions(+), 3 deletions(-)

diff --git a/mlir/test/Conversion/VectorToLLVM/vector-to-llvm-32b.mlir b/mlir/test/Conversion/VectorToLLVM/vector-to-llvm-32b.mlir
index 5a816eed8ab36..f7ff7d6be2ffb 100644
--- a/mlir/test/Conversion/VectorToLLVM/vector-to-llvm-32b.mlir
+++ b/mlir/test/Conversion/VectorToLLVM/vector-to-llvm-32b.mlir
@@ -1,10 +1,11 @@
 // The memref descriptor fields use the converted index type, which is not
-// necessarily `i64`.
+// necessarily `i64`. Note that dynamic=true is needed to ensure that the data
+// layout is considered.
 
-// RUN: mlir-opt %s --convert-to-llvm | FileCheck %s
+// RUN: mlir-opt %s --convert-to-llvm="dynamic=true" | FileCheck %s
 
 module attributes {dlti.dl_spec = #dlti.dl_spec<
-  #dlti.dl_entry<index, 32>,
+  #dlti.dl_entry<index, 32>
 >} {
   // CHECK-LABEL: llvm.func @type_cast
   //       CHECK:   %[[OFFSET:.*]] = llvm.mlir.constant(0 : index) : i32