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Package: coder

Control inlining in generated code




coder.inline('always') forces inlining of the current function in the generated code. Place the coder.inline directive inside the function to which it applies. The code generator does not inline entry-point functions and recursive functions. Also, the code generator does not inline functions into parfor loops, or inline functions called from parfor loops.

coder.inline('never') prevents inlining of the current function in the generated code. Prevent inlining when you want to simplify the mapping between the MATLAB® source code and the generated code. You can disable inlining for all functions at the command line by using the -O disable:inline option of the codegen command.

coder.inline('default') uses internal heuristics to determine whether to inline the current function. Usually, the heuristics produce highly optimized code. Use coder.inline only when you need to fine-tune these optimizations.


Prevent Function Inlining

In this example, function foo is not inlined in the generated code:

function y = foo(x)
  y = x;

Use coder.inline in Control Flow Statements

You can use coder.inline in control flow code. If the software detects contradictory coder.inline directives, the generated code uses the default inlining heuristic and issues a warning.

Suppose that you want to generate code for a division function used by a system with limited memory. To optimize memory use in the generated code, the inline_division function manually controls inlining based on whether it performs scalar division or vector division:

function y = inline_division(dividend, divisor)

% For scalar division, inlining produces smaller code
% than the function call itself.  
if isscalar(dividend) && isscalar(divisor)
% Vector division produces a for-loop.
% Prohibit inlining to reduce code size.

if any(divisor == 0)
   error('Cannot divide by 0');

y = dividend / divisor;

More About

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Technique that replaces a function call with the contents (body) of that function. Inlining eliminates the overhead of a function call, but can produce larger C/C++ code. Inlining can create opportunities for further optimization of the generated C/C++ code.

Introduced in R2011a