[Mlir-commits] [mlir] Fix remove dead values poison crash (PR #205966)

[llvmlistbot at llvm.org]

https://github.com/LouisLu060211 updated https://github.com/llvm/llvm-project/pull/205966

>From 58d1f2667a6802d0a232dfe8d575e210e1e0f8b9 Mon Sep 17 00:00:00 2001
From: LouisLu0602 <yaolu0602 at gmail.com>
Date: Wed, 24 Jun 2026 15:09:36 +0800
Subject: [PATCH 1/2] Fix crash in vectorizeOpPrecondition when vector sizes
 array is too short

[MLIR][Vector] Add regression test for bug #204100 (mixed static/dynamic vector sizes)

Remove accidentally created file vectorize-dynamic-mixed-sizes.mlir

Remove mlir_venv/ from .gitignore (directory already deleted)

Fix comment about regression test location in Vectorization.cpp

Correct the path in the comment from .../Linalg/transform/... to .../Linalg/...
(the test actually lives directly under Linalg). Also update the
related vector-to-llvm test for consistency.

remove venv

Remove lldb/python_api from .gitignore

Fix emitSilenceableFailure to use target->getLoc()

Fixing comments

Fix a.mlir crash

[mlir][RemoveDeadValues] Fix crash replacing dead operand with poison

updated

updated minor changes
---
 mlir/lib/Transforms/RemoveDeadValues.cpp      | 20 ++++++++++------
 .../Vector/transform-op-vector-to-llvm.mlir   |  2 +-
 mlir/test/Transforms/remove-dead-values.mlir  | 23 +++++++++++++++++++
 3 files changed, 37 insertions(+), 8 deletions(-)

diff --git a/mlir/lib/Transforms/RemoveDeadValues.cpp b/mlir/lib/Transforms/RemoveDeadValues.cpp
index f0a210a2ededb..ae46630c949de 100644
--- a/mlir/lib/Transforms/RemoveDeadValues.cpp
+++ b/mlir/lib/Transforms/RemoveDeadValues.cpp
@@ -520,14 +520,20 @@ static void processBranchOp(BranchOpInterface branchOp, RunLivenessAnalysis &la,
   }
 }
 
+/// Create ub.poison ops for the given values. If a value has no uses, return
+/// an "empty" value.
+static Value createPoisonedValue(OpBuilder &b, Value value) {
+  if (!value || value.use_empty())
+    return Value();
+  return ub::PoisonOp::create(b, value.getLoc(), value.getType()).getResult();
+}
+
 /// Create ub.poison ops for the given values. If a value has no uses, return
 /// an "empty" value.
 static SmallVector<Value> createPoisonedValues(OpBuilder &b,
                                                ValueRange values) {
-  return llvm::map_to_vector(values, [&](Value value) {
-    if (value.use_empty())
-      return Value();
-    return ub::PoisonOp::create(b, value.getLoc(), value.getType()).getResult();
+  return llvm::map_to_vector(values, [&](Value value) -> Value {
+    return createPoisonedValue(b, value);
   });
 }
 
@@ -689,9 +695,9 @@ static void cleanUpDeadVals(MLIRContext *ctx, RDVFinalCleanupList &list) {
       if (o.replaceWithPoison) {
         rewriter.setInsertionPoint(o.op);
         for (auto deadIdx : o.nonLive.set_bits()) {
-          o.op->setOperand(
-              deadIdx, createPoisonedValues(rewriter, o.op->getOperand(deadIdx))
-                           .front());
+          Value poisoned = createPoisonedValue(rewriter, o.op->getOperand(deadIdx));
+          if (poisoned)
+            o.op->setOperand(deadIdx, poisoned);
         }
       } else {
         o.op->eraseOperands(o.nonLive);
diff --git a/mlir/test/Dialect/Vector/transform-op-vector-to-llvm.mlir b/mlir/test/Dialect/Vector/transform-op-vector-to-llvm.mlir
index 271cdf0e059f4..1a3b38158a262 100644
--- a/mlir/test/Dialect/Vector/transform-op-vector-to-llvm.mlir
+++ b/mlir/test/Dialect/Vector/transform-op-vector-to-llvm.mlir
@@ -18,4 +18,4 @@ module attributes {transform.with_named_sequence} {
     } {legal_dialects = ["func", "llvm"]} : !transform.any_op
     transform.yield
   }
-}
+}
\ No newline at end of file
diff --git a/mlir/test/Transforms/remove-dead-values.mlir b/mlir/test/Transforms/remove-dead-values.mlir
index 64088ce15cd48..bbed2dc2e2feb 100644
--- a/mlir/test/Transforms/remove-dead-values.mlir
+++ b/mlir/test/Transforms/remove-dead-values.mlir
@@ -868,3 +868,26 @@ module @func_with_non_call_users {
   }
   spirv.EntryPoint "GLCompute" @callee
 }
+
+// -----
+
+// CHECK: pdl_interp.func private @matcher()
+// CHECK-LABEL: func.func private @callee()
+// CHECK: return
+module {
+  pdl_interp.func private @matcher(%arg0: !llvm.ptr) {
+    pdl_interp.finalize
+  }
+  module @rewriters {
+  }
+  func.func private @callee(%arg0: memref<f32>) -> memref<f32> {
+    %false = arith.constant false
+    %0 = scf.if %false -> (memref<f32>) {
+      scf.yield %arg0 : memref<f32>
+    } else {
+      %1 = bufferization.clone %arg0 : memref<f32> to memref<f32>
+      scf.yield %1 : memref<f32>
+    }
+    return %0 : memref<f32>
+  }
+}

>From 2dfa90aaab3542422b1e42e40557575470870a53 Mon Sep 17 00:00:00 2001
From: LouisLu0602 <yaolu0602 at gmail.com>
Date: Fri, 26 Jun 2026 14:46:54 +0800
Subject: [PATCH 2/2] minnor issues

---
 mlir/test/Dialect/Vector/transform-op-vector-to-llvm.mlir | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/mlir/test/Dialect/Vector/transform-op-vector-to-llvm.mlir b/mlir/test/Dialect/Vector/transform-op-vector-to-llvm.mlir
index 1a3b38158a262..271cdf0e059f4 100644
--- a/mlir/test/Dialect/Vector/transform-op-vector-to-llvm.mlir
+++ b/mlir/test/Dialect/Vector/transform-op-vector-to-llvm.mlir
@@ -18,4 +18,4 @@ module attributes {transform.with_named_sequence} {
     } {legal_dialects = ["func", "llvm"]} : !transform.any_op
     transform.yield
   }
-}
\ No newline at end of file
+}