Description
By default:
- Functions remain as separate hierarchy blocks in the RTL.
- All instances of a function, at the same level of hierarchy, uses the same RTL implementation (block).
The set_directive_function_instantiate
command is used to create a unique RTL implementation for each instance of a function,
allowing each instance to be optimized.
By default, the following code results in a single RTL implementation of
function foo_sub for all three instances.
char foo_sub(char inval, char incr)
{
return inval + incr;
}
void foo(char inval1, char inval2, char inval3,
char *outval1, char *outval2, char * outval3)
{
*outval1 = foo_sub(inval1, 1);
*outval2 = foo_sub(inval2, 2);
*outval3 = foo_sub(inval3, 3);
}Using the directive as shown in the example section below results in three
versions of function foo_sub, each independently optimized
for variable incr.
Syntax
set_directive_function_instantiate <location> <variable>-
<location>is the location (in the formatfunction[/label]) where the instances of a function are to be made unique. <variable><string>specifies which function argument<string>is to be specified as constant.
Options
This command has no options.
Examples
For the example code shown above, the following Tcl (or pragma placed in
function foo_sub) allows each instance of function foo_sub to be independently optimized with respect to input
incr.
set_directive_function_instantiate foo_sub incr