[Mlir-commits] [mlir] b4e4616 - [mlir] Return null from DenseElementsAttr::get on unsupported attribute types (#181159)

[llvmlistbot at llvm.org]

Author: Jueon Park
Date: 2026-02-12T16:31:56Z
New Revision: b4e4616342ca4c7a3c53b99d8d082fd17bfbbb10

URL: https://github.com/llvm/llvm-project/commit/b4e4616342ca4c7a3c53b99d8d082fd17bfbbb10
DIFF: https://github.com/llvm/llvm-project/commit/b4e4616342ca4c7a3c53b99d8d082fd17bfbbb10.diff

LOG: [mlir] Return null from DenseElementsAttr::get on unsupported attribute types (#181159)

`DenseElementsAttr::get(ShapedType, ArrayRef<Attribute>)` crashed with an unconditional `cast<IntegerAttr>` when encountering attribute types that are neither `FloatAttr` nor `IntegerAttr` (e.g. `ub.poison`). This can happen when folding ops like `tensor.from_elements` whose operands include poison values.

This patch fixes the issue at the `DenseElementsAttr::get` level rather than in individual op folders. The `cast<IntegerAttr>` is replaced with `dyn_cast<IntegerAttr>`, and when the attribute is neither `FloatAttr` nor `IntegerAttr`, a null `DenseElementsAttr` is returned. This is a more robust fix because it prevents the same class of crashes in any caller that passes unsupported attributes to `DenseElementsAttr::get`.

Fixes #178209.

---------

Co-authored-by: rebel-jueonpark <jueonpark at rebellions.ai>

Added: 
    

Modified: 
    mlir/lib/IR/BuiltinAttributes.cpp
    mlir/test/Dialect/Tensor/canonicalize.mlir

Removed: 
    


################################################################################
diff  --git a/mlir/lib/IR/BuiltinAttributes.cpp b/mlir/lib/IR/BuiltinAttributes.cpp
index fbbd9d29abe85..1a29fc534b40f 100644
--- a/mlir/lib/IR/BuiltinAttributes.cpp
+++ b/mlir/lib/IR/BuiltinAttributes.cpp
@@ -947,11 +947,13 @@ DenseElementsAttr DenseElementsAttr::get(ShapedType type,
       assert(floatAttr.getType() == eltType &&
              "expected float attribute type to equal element type");
       intVal = floatAttr.getValue().bitcastToAPInt();
-    } else {
-      auto intAttr = llvm::cast<IntegerAttr>(values[i]);
+    } else if (auto intAttr = llvm::dyn_cast<IntegerAttr>(values[i])) {
       assert(intAttr.getType() == eltType &&
              "expected integer attribute type to equal element type");
       intVal = intAttr.getValue();
+    } else {
+      // Unsupported attribute type.
+      return {};
     }
 
     assert(intVal.getBitWidth() == bitWidth &&

diff  --git a/mlir/test/Dialect/Tensor/canonicalize.mlir b/mlir/test/Dialect/Tensor/canonicalize.mlir
index 7a2d53c0c5850..e125ea3b62b44 100644
--- a/mlir/test/Dialect/Tensor/canonicalize.mlir
+++ b/mlir/test/Dialect/Tensor/canonicalize.mlir
@@ -398,6 +398,19 @@ func.func @extract_from_elements_complex_f() -> tensor<3xcomplex<f32>> {
 
 // -----
 
+// Ensure tensor.from_elements with poison values doesn't crash.
+// CHECK-LABEL: func @from_elements_with_poison
+func.func @from_elements_with_poison() -> tensor<1xindex> {
+  // CHECK: %[[POISON:.*]] = ub.poison : index
+  // CHECK: %[[TENSOR:.*]] = tensor.from_elements %[[POISON]] : tensor<1xindex>
+  // CHECK: return %[[TENSOR]]
+  %0 = ub.poison : index
+  %1 = tensor.from_elements %0 : tensor<1xindex>
+  return %1 : tensor<1xindex>
+}
+
+// -----
+
 // Ensure the optimization doesn't segfault from bad constants
 // CHECK-LABEL: func @extract_negative_from_tensor.from_elements
 func.func @extract_negative_from_tensor.from_elements(%element : index) -> index {