LargeTypesReg2Mem: Gracefully handle the case when the Container type is deemed small but the Containee is not

rdar://123340151

Author: aschwaighofer

lib/IRGen/LoadableByAddress.cpp

@@ -3459,6 +3459,19 @@ class AddressAssignment {
 
   SILValue getAddressForValue(SILValue v) {
     auto it = valueToAddressMap.find(v);
+
+    // This can happen if we deem a container type small but a contained type
+    // big.
+    if (it == valueToAddressMap.end()) {
+      if (auto *sv = dyn_cast<SingleValueInstruction>(v)) {
+        auto addr = createAllocStack(v->getType());
+        auto builder = getBuilder(++sv->getIterator());
+        builder.createStore(sv->getLoc(), v, addr,
+                            StoreOwnershipQualifier::Unqualified);
+        mapValueToAddress(v, addr);
+        return addr;
+      }
+    }
     assert(it != valueToAddressMap.end());
 
     return it->second;

test/IRGen/Inputs/large_c.h

@@ -29,3 +29,14 @@ struct SamplesType {
     void* Z;
     void* AA;
 };
+
+
+typedef struct _ContainedType {
+  unsigned int f1;
+  float    f2;
+} __attribute__((packed)) ContainedType;
+
+typedef struct _ContainerType {
+  char x1;
+  ContainedType l[10];
+}  __attribute__((packed)) ContainerType;

test/IRGen/loadable_by_address_reg2mem.sil

@@ -229,3 +229,22 @@ bb0(%0 : $SamplesType):
   %t = tuple ()
   return %t : $()
 }
+
+// In this test case Container type is identified as not large but contained
+// type is.
+sil @test9 : $@convention(thin) () -> () {
+bb0:
+  %0 = alloc_stack $_ContainerType
+  %1 = load %0 : $*_ContainerType
+  %2 = alloc_stack $(_ContainedType, _ContainedType, _ContainedType, _ContainedType, _ContainedType,
+                     _ContainedType, _ContainedType, _ContainedType, _ContainedType, _ContainedType)
+
+  %3 = struct_extract %1 : $_ContainerType, #_ContainerType.l
+  store %3 to %2 : $*(_ContainedType, _ContainedType, _ContainedType, _ContainedType, _ContainedType,
+                     _ContainedType, _ContainedType, _ContainedType, _ContainedType, _ContainedType)
+  dealloc_stack %2 : $*(_ContainedType, _ContainedType, _ContainedType, _ContainedType, _ContainedType,
+                     _ContainedType, _ContainedType, _ContainedType, _ContainedType, _ContainedType)
+  dealloc_stack %0 : $*_ContainerType
+  %t = tuple ()
+  return %t : $()
+}