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 <h3 class="section">2.5 Options for debugging your program or GNU Fortran</h3>

 <p><a name="index-options_002c-debugging-195"></a><a name="index-debugging-information-options-196"></a>
 GNU Fortran has various special options that are used for debugging
 either your program or the GNU Fortran compiler.

      <dl>
 <dt><code>-fdump-fortran-original</code><dd><a name="index-g_t_0040code_007bfdump_002dfortran_002doriginal_007d-197"></a>Output the internal parse tree after translating the source program
 into internal representation.  Only really useful for debugging the
 GNU Fortran compiler itself.

      <br><dt><code>-fdump-optimized-tree</code><dd><a name="index-g_t_0040code_007bfdump_002dfortran_002doptimized_007d-198"></a>Output the parse tree after front-end optimization.  Only really
 useful for debugging the GNU Fortran compiler itself.

      <p><a name="index-g_t_0040code_007bfdump_002dparse_002dtree_007d-199"></a>Output the internal parse tree after translating the source program
 into internal representation.  Only really useful for debugging the
 GNU Fortran compiler itself.  This option is deprecated; use
 <code>-fdump-fortran-original</code> instead.

      <br><dt><code>-ffpe-trap=</code><var>list</var><dd><a name="index-g_t_0040code_007bffpe_002dtrap_003d_007d_0040var_007blist_007d-200"></a>Specify a list of floating point exception traps to enable.  On most
 systems, if a floating point exception occurs and the trap for that
 exception is enabled, a SIGFPE signal will be sent and the program
 being aborted, producing a core file useful for debugging.  <var>list</var>
 is a (possibly empty) comma-separated list of the following
 exceptions: &lsquo;<samp><span class="samp">invalid</span></samp>&rsquo; (invalid floating point operation, such as
 <code>SQRT(-1.0)</code>), &lsquo;<samp><span class="samp">zero</span></samp>&rsquo; (division by zero), &lsquo;<samp><span class="samp">overflow</span></samp>&rsquo;
 (overflow in a floating point operation), &lsquo;<samp><span class="samp">underflow</span></samp>&rsquo; (underflow
 in a floating point operation), &lsquo;<samp><span class="samp">inexact</span></samp>&rsquo; (loss of precision
 during operation), and &lsquo;<samp><span class="samp">denormal</span></samp>&rsquo; (operation performed on a
 denormal value).  The first five exceptions correspond to the five
 IEEE 754 exceptions, whereas the last one (&lsquo;<samp><span class="samp">denormal</span></samp>&rsquo;) is not
 part of the IEEE 754 standard but is available on some common
 architectures such as x86.

      <p>The first three exceptions (&lsquo;<samp><span class="samp">invalid</span></samp>&rsquo;, &lsquo;<samp><span class="samp">zero</span></samp>&rsquo;, and
 &lsquo;<samp><span class="samp">overflow</span></samp>&rsquo;) often indicate serious errors, and unless the program
 has provisions for dealing with these exceptions, enabling traps for
 these three exceptions is probably a good idea.

      <p>Many, if not most, floating point operations incur loss of precision
 due to rounding, and hence the <code>ffpe-trap=inexact</code> is likely to
 be uninteresting in practice.

      <p>By default no exception traps are enabled.

      <br><dt><code>-fno-backtrace</code><dd><a name="index-g_t_0040code_007bfno_002dbacktrace_007d-201"></a><a name="index-backtrace-202"></a><a name="index-trace-203"></a>When a serious runtime error is encountered or a deadly signal is
 emitted (segmentation fault, illegal instruction, bus error,
 floating-point exception, and the other POSIX signals that have the
 action &lsquo;<samp><span class="samp">core</span></samp>&rsquo;), the Fortran runtime library tries to output a
 backtrace of the error. <code>-fno-backtrace</code> disables the backtrace
 generation. This option only has influence for compilation of the
 Fortran main program.

    </dl>

    <p>See <a href="../gcc/Debugging-Options.html#Debugging-Options">Options for Debugging Your Program or GCC</a>, for more information on
 debugging options.

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	<h3 class="section">2.5 Options for debugging your program or GNU Fortran</h3>

	<p><a name="index-options_002c-debugging-195"></a><a name="index-debugging-information-options-196"></a>
	GNU Fortran has various special options that are used for debugging
	either your program or the GNU Fortran compiler.

	<dl>
	<dt><code>-fdump-fortran-original</code><dd><a name="index-g_t_0040code_007bfdump_002dfortran_002doriginal_007d-197"></a>Output the internal parse tree after translating the source program
	into internal representation. Only really useful for debugging the
	GNU Fortran compiler itself.

	<br><dt><code>-fdump-optimized-tree</code><dd><a name="index-g_t_0040code_007bfdump_002dfortran_002doptimized_007d-198"></a>Output the parse tree after front-end optimization. Only really
	useful for debugging the GNU Fortran compiler itself.

	<p><a name="index-g_t_0040code_007bfdump_002dparse_002dtree_007d-199"></a>Output the internal parse tree after translating the source program
	into internal representation. Only really useful for debugging the
	GNU Fortran compiler itself. This option is deprecated; use
	<code>-fdump-fortran-original</code> instead.

	<br><dt><code>-ffpe-trap=</code><var>list</var><dd><a name="index-g_t_0040code_007bffpe_002dtrap_003d_007d_0040var_007blist_007d-200"></a>Specify a list of floating point exception traps to enable. On most
	systems, if a floating point exception occurs and the trap for that
	exception is enabled, a SIGFPE signal will be sent and the program
	being aborted, producing a core file useful for debugging. <var>list</var>
	is a (possibly empty) comma-separated list of the following
	exceptions: ‘<samp><span class="samp">invalid</span></samp>’ (invalid floating point operation, such as
	<code>SQRT(-1.0)</code>), ‘<samp><span class="samp">zero</span></samp>’ (division by zero), ‘<samp><span class="samp">overflow</span></samp>’
	(overflow in a floating point operation), ‘<samp><span class="samp">underflow</span></samp>’ (underflow
	in a floating point operation), ‘<samp><span class="samp">inexact</span></samp>’ (loss of precision
	during operation), and ‘<samp><span class="samp">denormal</span></samp>’ (operation performed on a
	denormal value). The first five exceptions correspond to the five
	IEEE 754 exceptions, whereas the last one (‘<samp><span class="samp">denormal</span></samp>’) is not
	part of the IEEE 754 standard but is available on some common
	architectures such as x86.

	<p>The first three exceptions (‘<samp><span class="samp">invalid</span></samp>’, ‘<samp><span class="samp">zero</span></samp>’, and
	‘<samp><span class="samp">overflow</span></samp>’) often indicate serious errors, and unless the program
	has provisions for dealing with these exceptions, enabling traps for
	these three exceptions is probably a good idea.

	<p>Many, if not most, floating point operations incur loss of precision
	due to rounding, and hence the <code>ffpe-trap=inexact</code> is likely to
	be uninteresting in practice.

	<p>By default no exception traps are enabled.

	<br><dt><code>-fno-backtrace</code><dd><a name="index-g_t_0040code_007bfno_002dbacktrace_007d-201"></a><a name="index-backtrace-202"></a><a name="index-trace-203"></a>When a serious runtime error is encountered or a deadly signal is
	emitted (segmentation fault, illegal instruction, bus error,
	floating-point exception, and the other POSIX signals that have the
	action ‘<samp><span class="samp">core</span></samp>’), the Fortran runtime library tries to output a
	backtrace of the error. <code>-fno-backtrace</code> disables the backtrace
	generation. This option only has influence for compilation of the
	Fortran main program.

	</dl>

	<p>See <a href="../gcc/Debugging-Options.html#Debugging-Options">Options for Debugging Your Program or GCC</a>, for more information on
	debugging options.

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