/Oq option ignored for __fastcall function 'function'
The fastcall and saveregs calling conventions are not allowed for p-code functions. The function was compiled into native code.
This warning can be avoided by using a different calling convention or by turning p-code generation off during the definition of fastcall and saveregs functions, as in:
#pragma optimize( "q", off ) //Turn p-code on
int __fastcall FastFunc( void )
{...};
#pragma optimize( "q" ) //Return to default p-code mode