HP aC++/HP C A.06.20 Programmer's Guide

+Ointeger_overflow
+Ointeger_overflow=kind
To provide the best runtime performance, the compiler makes assumptions that runtime
integer arithmetic expressions that arise in certain contexts do not overflow (produce
values that are too high or too low to represent) both expressions that are present in
user code and expressions that the compiler constructs itself. Note that if an integer
arithmetic overflow assumption is violated, runtime behavior is undefined.
+Ointeger_overflow=moderate is the default for all optimization levels. Previously,
+Ointeger_overflow=aggressive was the default at +O2 and above. This was
changed to enable a wider class of applications to be compiled with optimization and
run correctly.
The defined values of kind are:
aggressive
Allows the compiler to make a broad set of assumptions that integer
arithmetic expressions do not overflow.
conservative
Directs the compiler to make fewer assumptions that integer
arithmetic expressions do not overflow.
moderate This is the same as +Ointeger_overflow=aggressive, except
that linear function test replacement (LFTR) optimization is not
performed.
+Olevel
+Olevel=name1[,name2,...,nameN]
The +Olevel option lowers optimization to the specified level for one or more named
functions.
level can be 0, 1, 2, 3, or 4.
The name parameters are names of functions in the module being compiled. Use this
option when one or more functions do not optimize well or properly. This option must
be used with a basic +Olevel or -O option. Note that currently only the C++ mangled
name of the function is allowed for name.
This option works like the OPT_LEVEL pragma. The option overrides the pragma for
the specified functions. As with the pragma, you can only lower the level of
optimization; you cannot raise it above the level specified by a basic +Olevel or -O
option. To avoid confusion, it is best to use either this option or the OPT_LEVEL pragma
rather than both.
You can use this option at optimization levels 1, 2, 3, and 4. The default is to optimize
all functions at the level specified by the basic +Olevel or -O option.
78 Command-Line Options