1@c Copyright (C) 1988, 1989, 1992, 1993, 1994, 1995, 1996, 1997, 1998, 1999,
2@c 2000, 2001, 2002, 2003, 2004, 2005, 2006 Free Software Foundation, Inc.
3@c This is part of the GCC manual.
4@c For copying conditions, see the file gcc.texi.
5
6@ignore
7@c man begin INCLUDE
8@include gcc-vers.texi
--- 5663 unchanged lines hidden (view full) ---
5672
5673This option should never be turned on by any @option{-O} option since
5674it can result in incorrect output for programs which depend on
5675an exact implementation of IEEE or ISO rules/specifications for
5676math functions.
5677
5678The default is @option{-fmath-errno}.
5679
5680On Darwin and FreeBSD systems, the math library never sets @code{errno}.
5681There is therefore
5682no reason for the compiler to consider the possibility that it might,
5683and @option{-fno-math-errno} is the default.
5684
5685@item -funsafe-math-optimizations
5686@opindex funsafe-math-optimizations
5687Allow optimizations for floating-point arithmetic that (a) assume
5688that arguments and results are valid and (b) may violate IEEE or
5689ANSI standards. When used at link-time, it may include libraries
--- 3813 unchanged lines hidden (view full) ---
9503
9504The option @option{-mno-fp-ret-in-387} causes such values to be returned
9505in ordinary CPU registers instead.
9506
9507@item -mno-fancy-math-387
9508@opindex mno-fancy-math-387
9509Some 387 emulators do not support the @code{sin}, @code{cos} and
9510@code{sqrt} instructions for the 387. Specify this option to avoid
9511generating those instructions. This option is the default on
9512OpenBSD and NetBSD@. This option is overridden when @option{-march}
9513indicates that the target cpu will always have an FPU and so the
9514instruction will not need emulation. As of revision 2.6.1, these
9515instructions are not generated unless you also use the
9516@option{-funsafe-math-optimizations} switch.
9517
9518@item -malign-double
9519@itemx -mno-align-double
--- 4638 unchanged lines hidden ---
2@c 2000, 2001, 2002, 2003, 2004, 2005, 2006 Free Software Foundation, Inc.
3@c This is part of the GCC manual.
4@c For copying conditions, see the file gcc.texi.
5
6@ignore
7@c man begin INCLUDE
8@include gcc-vers.texi
--- 5663 unchanged lines hidden (view full) ---
5672
5673This option should never be turned on by any @option{-O} option since
5674it can result in incorrect output for programs which depend on
5675an exact implementation of IEEE or ISO rules/specifications for
5676math functions.
5677
5678The default is @option{-fmath-errno}.
5679
5680On Darwin and FreeBSD systems, the math library never sets @code{errno}.
5681There is therefore
5682no reason for the compiler to consider the possibility that it might,
5683and @option{-fno-math-errno} is the default.
5684
5685@item -funsafe-math-optimizations
5686@opindex funsafe-math-optimizations
5687Allow optimizations for floating-point arithmetic that (a) assume
5688that arguments and results are valid and (b) may violate IEEE or
5689ANSI standards. When used at link-time, it may include libraries
--- 3813 unchanged lines hidden (view full) ---
9503
9504The option @option{-mno-fp-ret-in-387} causes such values to be returned
9505in ordinary CPU registers instead.
9506
9507@item -mno-fancy-math-387
9508@opindex mno-fancy-math-387
9509Some 387 emulators do not support the @code{sin}, @code{cos} and
9510@code{sqrt} instructions for the 387. Specify this option to avoid
9511generating those instructions. This option is the default on
9512OpenBSD and NetBSD@. This option is overridden when @option{-march}
9513indicates that the target cpu will always have an FPU and so the
9514instruction will not need emulation. As of revision 2.6.1, these
9515instructions are not generated unless you also use the
9516@option{-funsafe-math-optimizations} switch.
9517
9518@item -malign-double
9519@itemx -mno-align-double
--- 4638 unchanged lines hidden ---