Merge pull request #82282 from nate-chandler/cherrypick/release/6.2/rdar151726387

6.2: [IRGen] Fix FixedArray of fixedSize 1 element addressing

Author: nate-chandler

lib/IRGen/GenArray.cpp

@@ -53,8 +53,15 @@ class ArrayTypeInfoBase : public BaseTypeInfo {
       return;
     }
     if (fixedSize == 1) {
-      // only one element to operate on
-      return body(addrs);
+      auto zero = llvm::ConstantInt::get(IGF.IGM.IntPtrTy, 0);
+      // only one element to operate on; index to it in each array
+      SmallVector<Address, 2> eltAddrs;
+      eltAddrs.reserve(addrs.size());
+      for (auto index : indices(addrs)) {
+        eltAddrs.push_back(Element.indexArray(IGF, addrs[index], zero,
+                                              getElementSILType(IGF.IGM, T)));
+      }
+      return body(eltAddrs);
     }
 
     auto arraySize = getArraySize(IGF, T);

validation-test/IRGen/rdar151726387.sil

@@ -0,0 +1,21 @@
+// RUN: %target-swift-frontend -parse-sil -emit-ir %s
+
+sil_stage canonical
+
+import Builtin
+import Swift
+
+struct O {
+  var arr: Builtin.FixedArray<1, I>
+  struct I {
+    var eyes: SIMD64<Int8>
+    var neighs: String
+  }
+}
+
+sil @copy : $@convention(thin) (@in_guaranteed O) -> (@out O) {
+entry(%out : $*O, %in : $*O):
+  copy_addr %in to [init] %out : $*O
+  %retval = tuple ()
+  return %retval : $()
+}