Corrupted argument on x86, aargh.

How tired I am, this so-called professional Pascal compiler is absolutely unusable for anything, how does it even manage to compile itself (sorry for the outburst, but it's driving me mad).

Run this test on i386/win32 or x86-64/win64 with -O3:

{$mode objfpc} {$modeswitch anonymousfunctions}
type
	pAdapter = ^Adapter;
	Adapter = record
		start: SizeUint;
		adaptee: procedure(p: pointer; a, b: SizeUint);
	end;

	procedure UseAdapter(ad: pAdapter; a, b: SizeUint);
	begin
		ad^.adaptee(nil, ad^.start + a, ad^.start + b);
	end;

var
	ad: Adapter;
	oops: boolean = false;

begin
	ad.start := 10;
	ad.adaptee :=
		procedure(p: pointer; a, b: SizeUint)
		begin
			if p <> nil then begin writeln('p = ', PtrUint(p), ', should be 0.'); oops := true; end;
			if a <> 110 then begin writeln('a = ', a, ', should be 110.'); oops := true; end;
			if b <> 1010 then begin writeln('b = ', a, ', should be 1010.'); oops := true; end;
		end;
	UseAdapter(@ad, 100, 1000);
	if oops then halt(1);
end.

My output, x86/64:
a = 4295020660, should be 110

i386/win32:
a = 4239476, should be 110