diff --git a/flang/runtime/allocatable.cpp b/flang/runtime/allocatable.cpp
--- a/flang/runtime/allocatable.cpp
+++ b/flang/runtime/allocatable.cpp
@@ -21,6 +21,9 @@
 
 void RTNAME(AllocatableInitIntrinsic)(Descriptor &descriptor,
     TypeCategory category, int kind, int rank, int corank) {
+  if (descriptor.IsAllocated()) {
+    return; // Bypass so AllocatableAllocate can raise the error.
+  }
   INTERNAL_CHECK(corank == 0);
   descriptor.Establish(TypeCode{category, kind},
       Descriptor::BytesFor(category, kind), nullptr, rank, nullptr,
@@ -29,6 +32,9 @@
 
 void RTNAME(AllocatableInitCharacter)(Descriptor &descriptor,
     SubscriptValue length, int kind, int rank, int corank) {
+  if (descriptor.IsAllocated()) {
+    return; // Bypass so AllocatableAllocate can raise the error.
+  }
   INTERNAL_CHECK(corank == 0);
   descriptor.Establish(
       kind, length, nullptr, rank, nullptr, CFI_attribute_allocatable);
@@ -36,6 +42,9 @@
 
 void RTNAME(AllocatableInitDerived)(Descriptor &descriptor,
     const typeInfo::DerivedType &derivedType, int rank, int corank) {
+  if (descriptor.IsAllocated()) {
+    return; // Bypass so AllocatableAllocate can raise the error.
+  }
   INTERNAL_CHECK(corank == 0);
   descriptor.Establish(
       derivedType, nullptr, rank, nullptr, CFI_attribute_allocatable);
diff --git a/flang/unittests/Runtime/Allocatable.cpp b/flang/unittests/Runtime/Allocatable.cpp
--- a/flang/unittests/Runtime/Allocatable.cpp
+++ b/flang/unittests/Runtime/Allocatable.cpp
@@ -94,3 +94,21 @@
   EXPECT_EQ(*a->OffsetElement<float>(), 3.4F);
   a->Destroy();
 }
+
+TEST(AllocatableTest, DoubleAllocation) {
+
+  // CLASS(*), ALLOCATABLE :: r
+  // ALLOCATE(REAL::r)
+  auto r{createAllocatable(TypeCategory::Real, 4, 0)};
+  EXPECT_FALSE(r->IsAllocated());
+  EXPECT_TRUE(r->IsAllocatable());
+  RTNAME(AllocatableAllocate)(*r);
+  EXPECT_TRUE(r->IsAllocated());
+
+  // Make sure AllocatableInitIntrinsic doesn't reset the decsriptor if it is
+  // allocated.
+  // ALLOCATE(INTEGER::r)
+  RTNAME(AllocatableInitIntrinsic)
+  (*r, Fortran::common::TypeCategory::Integer, 4);
+  EXPECT_TRUE(r->IsAllocated());
+}