-fast compiler option

The HP C/ANSI C -fast compiler option is a macro command that expands into an existing set of compiler options which, used together, result in optimum speed and build-times. This option is also provided for compatibility in porting other applications to HP-UX.




	NOTE: Do not use this option for programs that depend on IEEE standard floating-point denormalized numbers. Otherwise, different numericaL results may occur.

The -fast option expands to the following HP C/ANSI C options:

+O3 +nolooptransforms +Olibcalls +FPD +Oentrysched +Ofastaccess

+O3 optimizations include all +O2 optimizations as well as all subprograms within a single file. It also inlines certain subprograms within the input file.
+Onolooptransform disables transformation of eligible loops for improved cache performance.
+Olibcalls increases the runtime performance of code which calls the standard library routines.
+FPD enables a fast underflow mode on PA-7100 architectures or later where denormalized floating-point operands are flushed to zero.
+Oentrysched optimizes instruction scheduling on a procedure's entry and exit sequences.
+Ofastaccess optimizes code for fast access to global data items.

You can override any of the options in -fast by specifying a subsequent option after it.

-fast compiler option

Technical documentation

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