[Mlir-commits] [mlir] 00e247a - [mlir][ub] Add `m_Poison()` matcher (#185022)

llvmlistbot at llvm.org llvmlistbot at llvm.org
Fri Mar 6 08:54:42 PST 2026


Author: Jakub Kuderski
Date: 2026-03-06T16:54:37Z
New Revision: 00e247ad76fdd0cd5841193950c8d4927e3015f8

URL: https://github.com/llvm/llvm-project/commit/00e247ad76fdd0cd5841193950c8d4927e3015f8
DIFF: https://github.com/llvm/llvm-project/commit/00e247ad76fdd0cd5841193950c8d4927e3015f8.diff

LOG: [mlir][ub] Add `m_Poison()` matcher (#185022)

Add a dedicated matcher for poison values in the UB dialect, similar to
`m_Constant()` for general constants. The matcher uses
`PoisonAttrInterface` for future extensibility.

Replace existing checks against `ub::PoisonAttr` with the new matcher.

Assisted-by: claude

Added: 
    mlir/include/mlir/Dialect/UB/IR/UBMatchers.h

Modified: 
    mlir/lib/Dialect/Arith/IR/ArithOps.cpp
    mlir/lib/Dialect/Linalg/TransformOps/LinalgTransformOps.cpp
    mlir/lib/Dialect/Linalg/Transforms/PadTilingInterface.cpp
    mlir/lib/Dialect/Vector/IR/VectorOps.cpp
    mlir/test/IR/test-matchers.mlir
    mlir/test/lib/IR/TestMatchers.cpp

Removed: 
    


################################################################################
diff  --git a/mlir/include/mlir/Dialect/UB/IR/UBMatchers.h b/mlir/include/mlir/Dialect/UB/IR/UBMatchers.h
new file mode 100644
index 0000000000000..9dc29ac37691c
--- /dev/null
+++ b/mlir/include/mlir/Dialect/UB/IR/UBMatchers.h
@@ -0,0 +1,52 @@
+//===- UBMatchers.h - UB Dialect matchers -----------------------*- C++ -*-===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+//
+// This file provides matchers for the UB dialect, in particular for matching
+// poison values and attributes.
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef MLIR_DIALECT_UB_IR_UBMATCHERS_H
+#define MLIR_DIALECT_UB_IR_UBMATCHERS_H
+
+#include "mlir/Dialect/UB/IR/UBOps.h"
+#include "mlir/IR/Matchers.h"
+
+namespace mlir::ub {
+namespace detail {
+
+/// Matches a poison attribute (any attribute implementing PoisonAttrInterface).
+/// Supports matching against both Attribute and Operation* (via constant
+/// folding).
+struct poison_attr_matcher {
+  bool match(Attribute attr) { return isa<PoisonAttrInterface>(attr); }
+
+  bool match(Operation *op) {
+    Attribute attr;
+    if (!::mlir::detail::constant_op_binder<Attribute>(&attr).match(op))
+      return false;
+    return match(attr);
+  }
+};
+
+} // namespace detail
+
+/// Matches a poison constant (any attribute implementing PoisonAttrInterface).
+/// Works with `matchPattern` on Value, Operation*, and Attribute.
+///
+/// Examples:
+///   matchPattern(value, ub::m_Poison())   // Matches ub.poison op via Value.
+///   matchPattern(op, ub::m_Poison())      // Matches ub.poison op directly.
+///   matchPattern(attr, ub::m_Poison())    // Matches PoisonAttr(Interface).
+inline detail::poison_attr_matcher m_Poison() {
+  return detail::poison_attr_matcher();
+}
+
+} // namespace mlir::ub
+
+#endif // MLIR_DIALECT_UB_IR_UBMATCHERS_H

diff  --git a/mlir/lib/Dialect/Arith/IR/ArithOps.cpp b/mlir/lib/Dialect/Arith/IR/ArithOps.cpp
index b99f77fdc8b30..73fa0df80bcba 100644
--- a/mlir/lib/Dialect/Arith/IR/ArithOps.cpp
+++ b/mlir/lib/Dialect/Arith/IR/ArithOps.cpp
@@ -13,7 +13,7 @@
 
 #include "mlir/Dialect/Arith/IR/Arith.h"
 #include "mlir/Dialect/CommonFolders.h"
-#include "mlir/Dialect/UB/IR/UBOps.h"
+#include "mlir/Dialect/UB/IR/UBMatchers.h"
 #include "mlir/IR/Builders.h"
 #include "mlir/IR/BuiltinAttributeInterfaces.h"
 #include "mlir/IR/BuiltinAttributes.h"
@@ -460,7 +460,7 @@ arith::AddUIExtendedOp::fold(FoldAdaptor adaptor,
           adaptor.getOperands(),
           [](APInt a, const APInt &b) { return std::move(a) + b; })) {
     // If any operand is poison, propagate poison to both results.
-    if (isa<ub::PoisonAttr>(sumAttr)) {
+    if (matchPattern(sumAttr, ub::m_Poison())) {
       results.push_back(sumAttr);
       results.push_back(sumAttr);
       return success();
@@ -1919,7 +1919,7 @@ OpFoldResult arith::BitcastOp::fold(FoldAdaptor adaptor) {
     return {};
 
   /// Bitcast poison.
-  if (llvm::isa<ub::PoisonAttr>(operand))
+  if (matchPattern(operand, ub::m_Poison()))
     return ub::PoisonAttr::get(getContext());
 
   /// Bitcast integer or float to integer or float.
@@ -2503,10 +2503,10 @@ OpFoldResult arith::SelectOp::fold(FoldAdaptor adaptor) {
     return falseVal;
 
   // If either operand is fully poisoned, return the other.
-  if (isa_and_nonnull<ub::PoisonAttr>(adaptor.getTrueValue()))
+  if (matchPattern(adaptor.getTrueValue(), ub::m_Poison()))
     return falseVal;
 
-  if (isa_and_nonnull<ub::PoisonAttr>(adaptor.getFalseValue()))
+  if (matchPattern(adaptor.getFalseValue(), ub::m_Poison()))
     return trueVal;
 
   // select %x, true, false => %x

diff  --git a/mlir/lib/Dialect/Linalg/TransformOps/LinalgTransformOps.cpp b/mlir/lib/Dialect/Linalg/TransformOps/LinalgTransformOps.cpp
index ae65afac6b54c..d84408c024e25 100644
--- a/mlir/lib/Dialect/Linalg/TransformOps/LinalgTransformOps.cpp
+++ b/mlir/lib/Dialect/Linalg/TransformOps/LinalgTransformOps.cpp
@@ -27,7 +27,7 @@
 #include "mlir/Dialect/Transform/IR/TransformTypes.h"
 #include "mlir/Dialect/Transform/Interfaces/TransformInterfaces.h"
 #include "mlir/Dialect/Transform/Utils/Utils.h"
-#include "mlir/Dialect/UB/IR/UBOps.h"
+#include "mlir/Dialect/UB/IR/UBMatchers.h"
 #include "mlir/Dialect/Utils/IndexingUtils.h"
 #include "mlir/Dialect/Utils/StaticValueUtils.h"
 #include "mlir/Dialect/Vector/Transforms/LoweringPatterns.h"
@@ -2199,7 +2199,7 @@ transform::PadOp::apply(transform::TransformRewriter &rewriter,
     for (auto const &[untypedAttr, elementOrTensorType] :
          llvm::zip(getPaddingValues(), linalgTarget->getOperandTypes())) {
 
-      if (isa<ub::PoisonAttr>(untypedAttr)) {
+      if (matchPattern(untypedAttr, ub::m_Poison())) {
         paddingValues.push_back(untypedAttr);
         continue;
       }
@@ -2452,7 +2452,7 @@ transform::PadTilingInterfaceOp::apply(transform::TransformRewriter &rewriter,
       auto attr = dyn_cast<TypedAttr>(untypedAttr);
       Type elementType = getElementTypeOrSelf(elementOrTensorType);
 
-      if (isa<ub::PoisonAttr>(untypedAttr)) {
+      if (matchPattern(untypedAttr, ub::m_Poison())) {
         paddingValues.push_back(untypedAttr);
         continue;
       }

diff  --git a/mlir/lib/Dialect/Linalg/Transforms/PadTilingInterface.cpp b/mlir/lib/Dialect/Linalg/Transforms/PadTilingInterface.cpp
index 52ab92f180575..ab2629b41a463 100644
--- a/mlir/lib/Dialect/Linalg/Transforms/PadTilingInterface.cpp
+++ b/mlir/lib/Dialect/Linalg/Transforms/PadTilingInterface.cpp
@@ -11,7 +11,7 @@
 #include "mlir/Dialect/Affine/IR/AffineOps.h"
 #include "mlir/Dialect/Complex/IR/Complex.h"
 #include "mlir/Dialect/Tensor/IR/Tensor.h"
-#include "mlir/Dialect/UB/IR/UBOps.h"
+#include "mlir/Dialect/UB/IR/UBMatchers.h"
 #include "mlir/Dialect/Utils/StaticValueUtils.h"
 #include "mlir/IR/AffineExpr.h"
 #include "mlir/IR/BuiltinAttributes.h"
@@ -235,7 +235,7 @@ static Value padOperand(OpBuilder &builder, TilingInterface opToPad,
       paddingValue = complex::ConstantOp::create(builder, opToPad.getLoc(),
                                                  complexTy, complexAttr);
     }
-  } else if (isa<ub::PoisonAttr>(paddingValueAttr)) {
+  } else if (matchPattern(paddingValueAttr, ub::m_Poison())) {
     paddingValue = ub::PoisonOp::create(builder, opToPad.getLoc(),
                                         getElementTypeOrSelf(v.getType()));
   } else if (auto typedAttr = dyn_cast<TypedAttr>(paddingValueAttr)) {

diff  --git a/mlir/lib/Dialect/Vector/IR/VectorOps.cpp b/mlir/lib/Dialect/Vector/IR/VectorOps.cpp
index a3077d7313b93..7afcd7d3f88fb 100644
--- a/mlir/lib/Dialect/Vector/IR/VectorOps.cpp
+++ b/mlir/lib/Dialect/Vector/IR/VectorOps.cpp
@@ -20,7 +20,7 @@
 #include "mlir/Dialect/Bufferization/IR/BufferizableOpInterface.h"
 #include "mlir/Dialect/MemRef/IR/MemRef.h"
 #include "mlir/Dialect/Tensor/IR/Tensor.h"
-#include "mlir/Dialect/UB/IR/UBOps.h"
+#include "mlir/Dialect/UB/IR/UBMatchers.h"
 #include "mlir/Dialect/Utils/IndexingUtils.h"
 #include "mlir/Dialect/Utils/StructuredOpsUtils.h"
 #include "mlir/Dialect/Utils/VerificationUtils.h"
@@ -497,7 +497,7 @@ void VectorDialect::initialize() {
 Operation *VectorDialect::materializeConstant(OpBuilder &builder,
                                               Attribute value, Type type,
                                               Location loc) {
-  if (isa<ub::PoisonAttrInterface>(value))
+  if (matchPattern(value, ub::m_Poison()))
     return value.getDialect().materializeConstant(builder, value, type, loc);
 
   return arith::ConstantOp::materialize(builder, value, type, loc);
@@ -2112,7 +2112,7 @@ static Attribute foldPoisonIndexInsertExtractOp(MLIRContext *context,
 
 /// Fold a vector extract from is a poison source.
 static Attribute foldPoisonSrcExtractOp(Attribute srcAttr) {
-  if (isa_and_nonnull<ub::PoisonAttr>(srcAttr))
+  if (matchPattern(srcAttr, ub::m_Poison()))
     return srcAttr;
 
   return {};
@@ -2719,7 +2719,7 @@ static OpFoldResult foldFromElementsToConstant(FromElementsOp fromElementsOp,
                                                ArrayRef<Attribute> elements) {
   // Check for null or poison attributes before any processing.
   if (llvm::any_of(elements, [](Attribute attr) {
-        return !attr || isa<ub::PoisonAttrInterface>(attr);
+        return !attr || matchPattern(attr, ub::m_Poison());
       }))
     return {};
 
@@ -3168,7 +3168,7 @@ OpFoldResult BroadcastOp::fold(FoldAdaptor adaptor) {
   }
   if (auto attr = llvm::dyn_cast<SplatElementsAttr>(adaptor.getSource()))
     return DenseElementsAttr::get(vectorType, attr.getSplatValue<Attribute>());
-  if (llvm::dyn_cast<ub::PoisonAttr>(adaptor.getSource()))
+  if (matchPattern(adaptor.getSource(), ub::m_Poison()))
     return ub::PoisonAttr::get(getContext());
   return {};
 }
@@ -3323,8 +3323,8 @@ OpFoldResult vector::ShuffleOp::fold(FoldAdaptor adaptor) {
     return {};
 
   // Fold shuffle poison, poison -> poison.
-  bool isV1Poison = isa<ub::PoisonAttr>(v1Attr);
-  bool isV2Poison = isa<ub::PoisonAttr>(v2Attr);
+  bool isV1Poison = matchPattern(v1Attr, ub::m_Poison());
+  bool isV2Poison = matchPattern(v2Attr, ub::m_Poison());
   if (isV1Poison && isV2Poison)
     return ub::PoisonAttr::get(getContext());
 
@@ -4092,7 +4092,8 @@ class InsertStridedSliceConstantFolder final
       return failure();
 
     // TODO: Support poison.
-    if (isa<ub::PoisonAttr>(vectorDestCst) || isa<ub::PoisonAttr>(sourceCst))
+    if (matchPattern(vectorDestCst, ub::m_Poison()) ||
+        matchPattern(sourceCst, ub::m_Poison()))
       return failure();
 
     // TODO: Handle non-unit strides when they become available.
@@ -6584,7 +6585,7 @@ OpFoldResult ShapeCastOp::fold(FoldAdaptor adaptor) {
     return denseAttr.reshape(getType());
 
   // shape_cast(poison) -> poison
-  if (llvm::dyn_cast_if_present<ub::PoisonAttr>(adaptor.getSource()))
+  if (matchPattern(adaptor.getSource(), ub::m_Poison()))
     return ub::PoisonAttr::get(getContext());
 
   return {};
@@ -6940,7 +6941,7 @@ OpFoldResult vector::TransposeOp::fold(FoldAdaptor adaptor) {
     return splat.reshape(getResultVectorType());
 
   // Eliminate poison transpose ops.
-  if (llvm::dyn_cast_if_present<ub::PoisonAttr>(adaptor.getVector()))
+  if (matchPattern(adaptor.getVector(), ub::m_Poison()))
     return ub::PoisonAttr::get(getContext());
 
   // Eliminate identity transposes, and more generally any transposes that

diff  --git a/mlir/test/IR/test-matchers.mlir b/mlir/test/IR/test-matchers.mlir
index 31f1b6de18c4e..589ea58c38470 100644
--- a/mlir/test/IR/test-matchers.mlir
+++ b/mlir/test/IR/test-matchers.mlir
@@ -52,3 +52,13 @@ func.func @test3(%a: f32) -> f32 {
 // CHECK-LABEL: test3
 //       CHECK:   Pattern mul(*, add(*, m_Op("test.name"))) matched
 //       CHECK:   Pattern m_Attr("fastmath") matched and bound value to: fast
+
+func.func @test4(%a: f32) -> f32 {
+  %0 = ub.poison : f32
+  %1 = arith.constant 1.0 : f32
+  %2 = arith.addf %a, %1 : f32
+  return %2 : f32
+}
+
+// CHECK-LABEL: test4
+//       CHECK:   Pattern m_Poison() matched 1 times

diff  --git a/mlir/test/lib/IR/TestMatchers.cpp b/mlir/test/lib/IR/TestMatchers.cpp
index 60b962bbac091..fdd786f4c0d3a 100644
--- a/mlir/test/lib/IR/TestMatchers.cpp
+++ b/mlir/test/lib/IR/TestMatchers.cpp
@@ -7,6 +7,7 @@
 //===----------------------------------------------------------------------===//
 
 #include "mlir/Dialect/Arith/IR/Arith.h"
+#include "mlir/Dialect/UB/IR/UBMatchers.h"
 #include "mlir/IR/BuiltinOps.h"
 #include "mlir/IR/Matchers.h"
 #include "mlir/Interfaces/FunctionInterfaces.h"
@@ -132,7 +133,7 @@ static void test1(FunctionOpInterface f) {
                << countMatches(f, p17) << " times\n";
 }
 
-void test2(FunctionOpInterface f) {
+static void test2(FunctionOpInterface f) {
   auto a = m_Val(f.getArgument(0));
   FloatAttr floatAttr;
   auto p =
@@ -148,7 +149,7 @@ void test2(FunctionOpInterface f) {
     llvm::outs() << "Pattern add(add(a, constant), a) matched\n";
 }
 
-void test3(FunctionOpInterface f) {
+static void test3(FunctionOpInterface f) {
   arith::FastMathFlagsAttr fastMathAttr;
   auto p = m_Op<arith::MulFOp>(m_Any(),
                                m_Op<arith::AddFOp>(m_Any(), m_Op("test.name")));
@@ -163,6 +164,12 @@ void test3(FunctionOpInterface f) {
                  << fastMathAttr.getValue() << "\n";
 }
 
+static void test4(FunctionOpInterface f) {
+  auto poison = ub::m_Poison();
+  llvm::outs() << "Pattern m_Poison() matched " << countMatches(f, poison)
+               << " times\n";
+}
+
 void TestMatchers::runOnOperation() {
   auto f = getOperation();
   llvm::outs() << f.getName() << "\n";
@@ -172,6 +179,8 @@ void TestMatchers::runOnOperation() {
     test2(f);
   if (f.getName() == "test3")
     test3(f);
+  if (f.getName() == "test4")
+    test4(f);
 }
 
 namespace mlir {


        


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