title: How to disable double-precision math while compiling with GCC or/and IAR?
body: <p>My embedded C code is running on <code>Cortex M4F</code> which has single precision <code>FPU</code>. I am concerned about how often the compiler puts software-based double-precision math in places like</p>
  
  <p>**</p>
  
  <pre><code>float_var1 = 3.0 * int_var / float_var_2;
  (3.0 instead of 3.0f)
  </code></pre>
  
  <p>**</p>
  
  <p>I am afraid that I would miss some of these double constants. How can I locate all occurrences of slower double-precision math? Disabling double-precision or generating an error/warning with either <strong>sourcery GCC or IAR</strong> would do it.</p>
  
  <p>Please guide me the correct way to achieve my objective.</p>