Linker substitutions don't optimize as much as they can #1106
Description
Sample code:
static void Optimizable ()
{
if (IntPtr.Size == 8)
Console.WriteLine ("64bit");
else
Console.WriteLine ("32bit");
}Substitution xml:
<linker>
<assembly fullname="System.Private.CoreLib">
<type fullname="System.IntPtr">
<method signature="System.Int32 get_Size()" body="stub" value="8" />
</type>
</assembly>
</linker>Initial IL:
default void Optimizable () cil managed
{
.maxstack 2
.locals init (
bool V_0)
IL_0000: nop
IL_0001: call int32 native int::get_Size()
IL_0006: ldc.i4.8
IL_0007: ceq
IL_0009: stloc.0
IL_000a: ldloc.0
IL_000b: brfalse.s IL_001a
IL_000d: ldstr "64bit"
IL_0012: call void class [mscorlib]System.Console::WriteLine(string)
IL_0017: nop
IL_0018: br.s IL_0025
IL_001a: ldstr "32bit"
IL_001f: call void class [mscorlib]System.Console::WriteLine(string)
IL_0024: nop
IL_0025: ret
} // end of method Application::Optimizable
Post-linked IL:
default void Optimizable () cil managed
{
.maxstack 2
.locals init (
bool V_0)
IL_0000: nop
IL_0001: call int32 class [System.Private.CoreLib]System.IntPtr::get_Size()
IL_0006: ldc.i4.8
IL_0007: ceq
IL_0009: stloc.0
IL_000a: ldloc.0
IL_000b: pop
IL_000c: ldstr "64bit"
IL_0011: call void class [mscorlib]System.Console::WriteLine(string)
IL_0016: nop
IL_0017: br.s IL_0019
IL_0019: ret
} // end of method Application::Optimizable
it seems the optimized C# would be:
static void Optimizable ()
{
if (IntPtr.Size == 8)
Console.WriteLine ("64bit");
}But we can do better, I want the optimized C# to look like this:
static void Optimizable ()
{
Console.WriteLine ("64bit");
}Desired IL:
default void Optimized () cil managed
{
.maxstack 8
IL_0000: ldstr "64bit"
IL_0005: call void class [mscorlib]System.Console::WriteLine(string)
IL_000c: ret
} // end of method Application::Optimized