diff --git a/flang/lib/Optimizer/Analysis/AliasAnalysis.cpp b/flang/lib/Optimizer/Analysis/AliasAnalysis.cpp
index f723e8f66e3e4..ed1101dc5e8d8 100644
--- a/flang/lib/Optimizer/Analysis/AliasAnalysis.cpp
+++ b/flang/lib/Optimizer/Analysis/AliasAnalysis.cpp
@@ -33,7 +33,11 @@ static bool isDummyArgument(mlir::Value v) {
   if (!blockArg)
     return false;
 
-  return blockArg.getOwner()->isEntryBlock();
+  mlir::Block *owner = blockArg.getOwner();
+  if (!owner->isEntryBlock() ||
+      !mlir::isa<mlir::FunctionOpInterface>(owner->getParentOp()))
+    return false;
+  return true;
 }
 
 /// Temporary function to skip through all the no op operations
diff --git a/flang/lib/Optimizer/Transforms/AddAliasTags.cpp b/flang/lib/Optimizer/Transforms/AddAliasTags.cpp
index 684aa4462915e..3642a812096db 100644
--- a/flang/lib/Optimizer/Transforms/AddAliasTags.cpp
+++ b/flang/lib/Optimizer/Transforms/AddAliasTags.cpp
@@ -105,6 +105,7 @@ static std::string getFuncArgName(mlir::Value arg) {
          "arg is a function argument");
   mlir::FunctionOpInterface func = mlir::dyn_cast<mlir::FunctionOpInterface>(
       blockArg.getOwner()->getParentOp());
+  assert(func && "This is not a function argument");
   mlir::StringAttr attr = func.getArgAttrOfType<mlir::StringAttr>(
       blockArg.getArgNumber(), "fir.bindc_name");
   if (!attr)
diff --git a/flang/test/Transforms/tbaa.fir b/flang/test/Transforms/tbaa.fir
index 7825ae60c71e6..f94bbe4bf9485 100644
--- a/flang/test/Transforms/tbaa.fir
+++ b/flang/test/Transforms/tbaa.fir
@@ -173,3 +173,40 @@
 // CHECK:           fir.store %[[VAL_8]] to %[[VAL_12]] : !fir.ref<i32>
 // CHECK:           return
 // CHECK:         }
+
+// -----
+
+// Make sure we don't mistake other block arguments as dummy arguments:
+
+omp.declare_reduction @add_reduction_i32 : i32 init {
+^bb0(%arg0: i32):
+  %c0_i32 = arith.constant 0 : i32
+  omp.yield(%c0_i32 : i32)
+} combiner {
+^bb0(%arg0: i32, %arg1: i32):
+  %0 = arith.addi %arg0, %arg1 : i32
+  omp.yield(%0 : i32)
+}
+
+func.func @_QQmain() attributes {fir.bindc_name = "reduce"} {
+  %c10_i32 = arith.constant 10 : i32
+  %c6_i32 = arith.constant 6 : i32
+  %c-1_i32 = arith.constant -1 : i32
+  %0 = fir.address_of(@_QFEi) : !fir.ref<i32>
+  %1 = fir.declare %0 {uniq_name = "_QFEi"} : (!fir.ref<i32>) -> !fir.ref<i32>
+  omp.parallel reduction(@add_reduction_i32 %1 -> %arg0 : !fir.ref<i32>) {
+// CHECK: omp.parallel reduction({{.*}}) {
+    %8 = fir.declare %arg0 {uniq_name = "_QFEi"} : (!fir.ref<i32>) -> !fir.ref<i32>
+// CHECK-NEXT: %[[DECL:.*]] = fir.declare
+    fir.store %c-1_i32 to %8 : !fir.ref<i32>
+// CHECK-NOT: fir.store %{{.*}} to %[[DECL]] {tbaa = %{{.*}}} : !fir.ref<i32>
+// CHECK:     fir.store %{{.*}} to %[[DECL]] : !fir.ref<i32>
+    omp.terminator
+  }
+  return
+}
+
+fir.global internal @_QFEi : i32 {
+  %c0_i32 = arith.constant 0 : i32
+  fir.has_value %c0_i32 : i32
+}