tests/codegen/mangling.d: change argument type of naked_dFunc to int (#4661)

Avoid issues on x86 with the calling convention by having an int
argument, which can be passed through a register, therefore, lifting
the burden of cleaning the stack, instead of a double.

Signed-off-by: Andrei Horodniceanu <[email protected]>

Author: the-horo

tests/codegen/inputs/mangling_definitions.d

@@ -46,6 +46,8 @@ version(AsmX86)
     else
         static assert(naked_cppFunc.mangleof == "_ZN15cpp_naked_funcs13naked_cppFuncEd");
 
-    int naked_dFunc(double a) { asm { naked; ret; } }
-    static assert(naked_dFunc.mangleof == "_D11definitions11naked_dFuncFdZi");
+    // Pass an int instead of a double due to x86 calling convetion
+    // See: https://github.com/ldc-developers/ldc/pull/4661
+    int naked_dFunc(int a) { asm { naked; ret; } }
+    static assert(naked_dFunc.mangleof == "_D11definitions11naked_dFuncFiZi");
 }

tests/codegen/mangling.d

@@ -61,8 +61,8 @@ version(AsmX86)
     extern(C++, decl_cpp_naked_funcs) pragma(mangle, nakedCppFuncMangle)
     int decl_naked_cppFunc(double a);
 
-    pragma(mangle, "_D11definitions11naked_dFuncFdZi")
-    int decl_naked_dFunc(double a);
+    pragma(mangle, "_D11definitions11naked_dFuncFiZi")
+    int decl_naked_dFunc(int a);
 }
 
 // Interfacing with C via pragma(mangle, …), without having to take care
@@ -84,7 +84,7 @@ void main()
     {
         decl_naked_cFunc(1.0);
         decl_naked_cppFunc(2.0);
-        decl_naked_dFunc(3.0);
+        decl_naked_dFunc(3);
     }
 
     assert(decl_cos(0.0) == 1.0);