Fixed: union type was incorrectly calculated

spec/compiler/codegen/tuple_spec.cr

@@ -101,4 +101,13 @@ describe "Code gen: tuple" do
       p.value[0] + p.value[1]
       ").to_i.should eq(3)
   end
+
+  it "codegens tuple union (bug because union size was computed incorrectly)" do
+    run(%(
+      require "prelude"
+      x = 1 == 1 ? {1, 1, 1} : {1}
+      i = 2
+      x[i]
+      )).to_i.should eq(1)
+  end
 end

src/compiler/crystal/codegen/llvm_typer.cr

@@ -124,10 +124,11 @@ module Crystal
         end
 
         ifdef x86_64
-          max_size /= 8
+          max_size /= 8.0
         else
-          max_size /= 4
+          max_size /= 4.0
         end
+        max_size = max_size.ceil
 
         max_size = 1 if max_size == 0